Tritiated Water Task Force Report

Transcription

1 Tritiated Water Task Force Report June 2016 Tritiated Water Task Force

2 Tritiated Water Task Force Report (Outline) As one of the countermeasures for treatin contaminated water at Tokyo Electric Power Company Holdins Fukushima Daiichi Nuclear Power Station (hereafter referred to as Fukushima Daiichi NPS ), various options underwent technical assesss meant to serve as basic data for determinin how to handle, over a lon period, water treated by multi-nuclide removal equip, etc. (hereafter referred to as tritiated water ). (This is not meant to reconcile the opinions of related parties or consolidate the options.) Overview of Basic Information In addition to oranizin information on tritium, which is a radioactive isotope of hydroen (hydroen-3), and its physical properties, its environal fate, and its impact on the environ and humans, the state of tritium at Fukushima Daiichi NPS, reulatory standards for tritium, and examples of handlin it in Japan and abroad were compiled as basic information. Options for Handlin Tritiated Water and Option Assess Based on examples from other countries and the like, scenarios under assess were established and technical assesss were carried out on the basis of conditions for treat which were standardized in order to compare, side-by-side, 11 options consistin of five methods and pre-treats. eosphere injection (no pre-treat/ post-dilution/ post-separation) offshore release (post-dilution/ post-separation) vapor release (no pre-treat/ post-dilution/ post-separation) hydroen release (no pre-treat/ post-separation) underround burial (no pre-treat) (Main Conditions) Volume to be Treated: 0.8 m 3 ; Volume to be Treated per Day: 400 m 3 Concentration in Raw Water: 4.2 or 0.5 Concentration to be Treated: leally permitted concentration Items for assess were established for the assess, with technical feasibility

3 and reulatory feasibility established as the basic requires, and the duration required for the treat, the costs, the scale, secondary waste, radiation exposure of workers, and other conditions established as potentially restrictin conditions. (The results of the estimations are approximations made under fixed hypothetical conditions and they are not uarantees of the details for the actual treat.) Also, based on the results from verification tests of tritium separation technoloies, since isotopic separation was not found to be a technoloy which could be immediately utilized, the duration and costs required for separation are not addressed.

4 Contents 1. Introduction 2 2. Goals and Assumptions of this Task Force 2 3. Overview of Basic Information (1) Physical Properties of Tritium 3 (2) Environal Fate and Impact of Tritium 3 (3) State of Tritium at Fukushima Daiichi NPS 4 (4) Reulatory Standards for Tritium 5 (5) Examples in Japan and Abroad 6 4. Options for Handlin Tritiated Water and Option Assess (1) Overview of Options 7 (2) Items for Assess 8 (3) Conditions Established for Comparative Assess 9 (4) Concrete Scenarios Established for Each Option 9 (5) Conceptual Desin for Each Scenario under Assess 11 (6) Assess Results for Each Scenario under Assess Conclusion 13 Tritiated Water Task Force Member List 14 Tritiated Water Task Force Meetin Record 15 1

5 1. Introduction A docu entitled Preventative and Multilayered Measures- Utilizin Enhanced Comprehensive Risk Manae- for Contaminated Water Treat at Tokyo Electric Power Company s Fukushima Daiichi Nuclear Power Station was compiled under the Committee on Countermeasures for Contaminated Water Treat on December 10th, Therein, it became clear that even if the various countermeasures of removin contamination sources, isolatin water from contamination sources, and preventin leakae of contaminated water were adopted, there would ultimately still be risks associated with storin water treated by multi-nuclide removal equip, etc. (hereafter referred to as tritiated water ). Thus, the Tritiated Water Task Force was established under the Committee on Countermeasures for Contaminated Water Treat, with the oal of assessin the various options pertainin to handlin tritiated water, and discussions commenced on December 25th, At the recommendation of the IAEA (International Atomic Enery Aency) investiative committee to examine all options pertainin to handlin tritiated water, the Nuclear Emerency Response Headquarters made a point, in the Additional Measures for Decommissionin and Contaminated Water Issues at Tokyo Electric Power Company s Fukushima Daiichi Nuclear Power Station decided on December 20, 2013, about contemplatin countermeasures by urently implein a comprehensive assess of all options pertainin to handlin tritiated water, for which the lare-volume storae thereof will still pose risks even after additional measures have been adopted. 2. Goals and Assumptions of this Task Force Amonst the contaminated water issues at Tokyo Electric Power Company Holdins Fukushima Daiichi Nuclear Power Station (hereafter referred to as Fukushima Daiichi NPS ), the oal of this task force is to elicit various options, such as separation, storae, release, etc., which can serve as basic data for determinin how to handle, over a lon period, tritiated water in particular, and also to carry out technical assesss for each of those options reardin the technical feasibility, reulatory feasibility, and the duration and costs required for handlin the water. (This is not meant to reconcile the opinions of related parties or consolidate the options.) 2

6 The assesss operate on the assumption that non-tritium isotopes will be removed separately by means of multi-nuclide removal equip, etc. 3. Overview of Basic Information (1) Physical Properties of Tritium (Reference Material 1) - Tritium is an isotope of hydroen (hydroen-3) containin two neutrons in addition to a proton and electron. - The half-life of tritium is 12.3 years. Tritium that enters the body is metabolized and half the amount is excreted from the body in approximately 10 days when it is in water and in approximately 40 days when it is in oranic matter (bioloical half-life). - Tritium has low enery beta rays (18.6 kev maximum), which can be shielded by a sinle sheet of paper. (2) Environal Fate and Impact of Tritium (Reference Materials 2 6) (A) Environal Fate of Tritium - Tritium that is released into the atmosphere exhibits such behaviors as turbulent diffusion in the atmosphere, dry or wet deposition on the earth s surface, advection or diffusion underround, and evaporation from the earth s surface. Since the state of diffusion varies reatly dependin on the meteoroloical conditions release, a simple assess is difficult. - For tritium that is released offshore, althouh it depends on how and where it is released, the concentration decreases as it ains distance from the site where it was released. (It is estimated (takin into consideration only advection and diffusion due to oceanic currents) that the concentration decreases by approximately one diit at approximately 10 km downstream, decreases by approximately two diits at approximately 50 km downstream, and decreases by approximately three diits at approximately 100 km downstream.) -Since approximately Bq of tritium is produced annually from cosmic rays, tritium also occurs naturally, and approximately 1 is present in natural water, and approximately 100 Bq/person is present in the human body (of a 65 k person). In the past, tritium oriinatin from atmospheric nuclear tests ( ) was present in the environ at approximately Bq. As of 2010, the amount of tritium present in the environ was approximately Bq. 3

7 (B) Environal Impact of Tritium - In oranic matter, tritium is found as FWT (free water tritium) and OBT (oranically bound tritium). Since OBT is easily absorbed by oranisms and has a lon bioloical half-life, it is important in terms of dose assesss. - In aquatic environs, the FWT concentration in oranisms and the tritium concentration in water rapidly reach equilibrium (becomin almost equivalent), and with bioaccumulation from water not bein confirmed in certain oranisms, the concentration factor of tritium (ratio of concentration in water to concentration in oranisms) is considered to be one or less. - Dose assesss on marine oranisms are performed usin typical oranisms (for example marine oranisms of different varieties such as flounder, trout, and crabs) as subjects. Dose assesss are enerally calculated from the concentration (Bq/k raw) (*1) of radioactive material, usin a conversion factor. For example, supposin that in bottom-dwellin fish tritium is uniformly distributed throuhout the bodies of the subject oranisms, the concentration of tritium in the sea water is the leally permitted concentration of 60,000, and the concentration factor is one, then the absorbed dose rate would be mgy/day (*2). In assesss by the NCRP (United States National Council on Radiation Protection and Measures) and the IAEA (International Atomic Enery Aency), aquatic oranism populations were found to be sufficiently protected when chronic absorbed dose rates are 10 mgy/day or less. Accordinly, as lon as considerably hih concentrations of tritium are not continually present in aquatic environs, there is not considered to be sinificant impact on aquatic oranisms. (*1) This unit represents concentrations measured in a state in which the environal samples have not been dried. (*2) Absorbed doses represent the amount of enery from radiation absorbed by the affected body per unit mass, and the units are expressed in Gy (Gray). Note that dose equivalents are used when the type of radiation and affected tissue are taken into consideration in convertin the absorbed doses to express the impact on the human body, and the units are expressed in Sv (Sieverts). (C) Impact of Tritium on the Human Body - Tritium is much less harmful, approximately 1/1000 as harmful, to the human body than radioactive cesium, which was used to establish the standard for radioactive material in food. 4

8 - Since tritium is a low-enery beta-ray radionuclide, external exposure is limited but inestin tritium in the body is considered to result in internal exposure. - As described above, tritium is found in oranisms in two forms, FWT (free water tritium) and OBT (oranically bound tritium), and accordin to the ICRP (International Commission on Radioloical Protection) the half-life of tritium in oranisms is considered to be approximately 10 days in the case of FWT, and approximately 40 days in the case of OBT. - In terms of measure data for the concentration of tritium in the surface seawater off the coast of Fukushima (at depths up to meters deep), exploratory results (June 2011) revealed that the backround tritium concentration level (0.07 ) increased to 0.15 after the nuclear accident (an increase of 0.08 Bq per 1 liter of sea water). If the impact on the human body is estimated based on this value, supposin that fish took in the entire amount of tritium as OBT (0.15 Bq/k) and a human inested 60 kilorams of that fish a year, the annual exposure amount (subtractin backround radiation exposure) would be approximately msv. (3) State of Tritium at Fukushima Daiichi NPS (Reference Material 7) - As of March 2016, there was approximately 820,000 m 3 of contaminated water in total bein stored within the tanks, of which, 620,000 m 3 of water had underone purification treat by means of multi-nuclide removal equip. - The concentration of tritium in the water stored in the tanks differs accordin to the storae period, since it is radually decreasin due to bein diluted from roundwater inflowin to the buildin, but the concentration at the time of storae ranes from approximately (September 2011 March 2016). Takin into account decay correction as of March 2016, the concentration is approximately and the cumulative amount of tritium contained in the water stored in the tanks is approximately Bq (approximately 2.1(*)) (as of March 24th, 2016). (*) This is the correspondin amount if the tritium was present as T (tritium atoms). (4) Reulatory Standards for Tritium (Reference Material 8) (A) Reulatory Standards for Normally Operatin Nuclear Power Plants - In the Rules for Installation, Operation, etc. of Commercial Power Reactors which were enacted on the basis of the Act on the Reulation of Nuclear Source Material, Nuclear Fuel Material and Reactors (hereinafter referred to 5

9 as Reactor Reulation Act ), it is required that when radioactive waste in aseous form is bein dischared usin exhaust equip, the concentration of the radioactive material in the exhaust air comin from the exhaust outlet or the exhaust air monitorin equip must be monitored such that the concentration of the radioactive material in the atmosphere beyond the exclusion zone does not exceed the concentration limit (*) declared by the Nuclear Reulation Authority. Moreover, when radioactive waste in liquid form is bein dischared by means of wastewater equip, it is required that the concentration of the radioactive material in the wastewater comin from the wastewater outlet or the wastewater monitorin equip must be monitored such that the concentration of the radioactive material in the water outside of the boundaries of exclusion zone does not exceed the concentration limit declared by the Nuclear Reulation Authority. - Furthermore, in the Notification for Radiation Dose Rate Limits, etc. Based on the Provisions of the Rules for Installation, Operation, etc. of Commercial Power Reactors which was enacted on the basis of the aboveioned rules, it is required that the sum of the followin is less than one: the fraction relative to an effective dose of 1 msv/year from external exposure, the sum of the fractions relative to the concentration limits for radioactive materials in air, and sum of the fractions relative to the concentration limits for radioactive materials in water. (*) This value accounts for an exposure dose of 1 msv/year for only one type of isotope. If tritium is the only radioactive material, then the concentration limit for the concentration in the air is 5, when the radiation is in vapor form, and 70,000, when the radiation is in in hydroen as form, and the concentration limit for the concentration in water is 60,000. (B) Reulatory Standards for Specified Nuclear Facility Fukushima Daiichi NPS - In the Rules Pertainin to the Safety of the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station Reactor Facilities and Protection Aainst Specified Nuclear Fuel Materials enacted on the basis of the Reactor Reulation Act, it is required that when radioactive waste in aseous form is bein dischared usin exhaust equip, the concentration of the radioactive material in the exhaust air comin from the exhaust outlet or the exhaust air monitorin equip must be monitored such that the concentration of the radioactive material in the atmosphere beyond the 6

10 exclusion zone does not exceed the concentration limit (*) declared by the Nuclear Reulation Authority. Moreover, when radioactive waste in liquid form is bein dischared by means of wastewater equip, it is required that the concentration of the radioactive material in the wastewater comin from the wastewater outlet or the wastewater monitorin equip does not exceed the concentration limit declared by the Nuclear Reulation Authority. - Furthermore, in the Notification for Vital Matters Pertainin to the Safety of the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station Reactor Facilities and Protection Aainst Specified Nuclear Fuel Materials which was enacted on the basis of the aboveioned reulations, it is required that the sum of the followin is less than one: the fraction relative to an effective dose of 1 msv/year from external exposure, the sum of the fractions relative to the concentration limits for radioactive materials in air, and sum of the fractions relative to the concentration limits for radioactive materials in water. (*) This value accounts for an exposure dose of 1 msv/year for only one type of isotope. If tritium is the only radioactive material, then the concentration limit for the concentration in the air is 5, when the radiation is in vapor form, and 70,000, when the radiation is in in hydroen as form, and the concentration limit for the concentration in water is 60,000. (C) Reulatory Standards for Food - When standard values pertainin to radioactive material in food were established in 2012, it was concluded that it is difficult to conceive of the concentration of tritium in food reachin a dose that would require attention (Report by the Workin Group on Radioactive Materials Measures, Food Sanitation Subcommittee, Pharmaceutical Affairs and Food Sanitation Council, Ministry of Health, Labour, and Welfare), so no standard value was established for tritium. (5) Examples of Handlin Tritium in Japan and Abroad (Reference Materials 9 13) (A) Example in America - In the nuclear accident at Three Mile Island, approximately Bq (approximately 8,700 m 3 ) of tritium were disposed of by means of vapor release into the atmosphere. - The NRC (United States Nuclear Reulatory Commission) assessed that nine 7

11 options out of 24 options had extremely low impact, and from those, vapor release was selected after the plant operator explained the options to stakeholders. After the accident, 10 years were required to initiate the disposal treat, and another three years were required to conclude the disposal treat. (At the Three Mile Island Nuclear Generatin Station the volume of water increasin was minimal and there was sufficient storae capacity, so there was leeway for operatin over a lon period of time). (B) Example in France - The annual quantity of tritium released at the La Haue reprocessin plant is approximately Bq in liquid form, and approximately Bq in aseous form. Althouh the total quantity of radioactive material released into the environ has been on the decrease in the last 20 years, the quantity of tritium released is not decreasin because tritium cannot be processed. - Althouh tritium was internationally reconized as havin minimal effects on health, since the necessity of assessin tritium in oranic matter was reconized domestically, the ASN (Nuclear Safety Authority) compiled a report entitled Tritium White Paper in Technoloies from around the world for removin tritium were explored in the process of compilin the report, but it was concluded that none of them could be adopted since none could resolve the problem at an acceptable cost, and consensus was also reached with stakeholders. After first compilin the report, the roup in chare has reularly compiled and presented reports explainin the latest possibilities pertainin to tritium processin methods, and ASN has been scrutinizin these. (C) Example in Enland - At the EU s Joint European Torus (JET), which was established at the Culham Center for Fusion Enery and which creates fuel from deuterium and tritium, there is a facility which uses electrolysis and cryoenic separation, etc., to collect tritium from coolants and the like containin hih concentrations of tritium. This treat method was selected throuh a preliminary review which narrowed 30 options total down to 10 options, followed by assessin 16 items total related to applicability/feasibility, economical efficiency, environal impact, health/safety, and reulations/international relations. (D) Example in Japan 8

12 - At nuclear power plants in Japan, tritium is dischared accordin to the reulatory standards in (4) (A) above. - The volume of tritium released offshore per one nuclear power plant in Japan raned from Bq Bq in the 2010 fiscal year (differs dependin on power plant). 4. Options for Handlin Tritiated Water and Option Assess (Refer to Appendix 1 for Details) (1) Overview of Options - Based on examples from other countries, five methods were chosen as methods for handlin tritiated water over a lon period, and these were oranized into the followin 11 options which resulted from combinin each with either no pre-treat process, with a dilution process, or with an isotopic separation process (*) (hereafter referred to as separation ). eosphere injection (no pre-treat/ post-dilution/ post-separation) offshore release (post-dilution/ post-separation) vapor release (no pre-treat/ post-dilution/ post-separation) hydroen release (no pre-treat/ post-separation) underround burial (no pre-treat) (*) The depleted product after isotopic separation is treated. (A) Dispose of by Injection into Geosphere (hereafter referred to as eosphere injection ) - Utilizin a compressor, tritiated water which either underoes no pre-treat, or underoes dilution or separation is injected into deep eosphere layers (2,500 m deep) throuh an underround pipeline, after safety has been ensured. (B) Offshore Release - Tritiated water which underoes dilution or separation is released offshore, after safety has been ensured. Note that in the dilution scenario, the method for securin the diluent water may chane dependin on the dilution factor. (C) Release as Vapor into Atmosphere (hereafter referred to as vapor release ) - Tritiated water which either underoes no pre-treat, or underoes dilution or separation, oes throuh evaporation processin, and a vapor containin tritium 9

13 is sent to evaporation equip and is released from an exhaust pipe into the atmosphere as a hih-temperature vapor, after safety has been ensured. (D) Reduce to Hydroen and Release as Hydroen Gas into Atmosphere (hereafter referred to as hydroen release ) - Tritiated water which either underoes no pre-treat or underoes separation is reduced to hydroen by means of electrolysis, and is released into the atmosphere, after safety has been ensured. (E) Solidify or Gelify and Dispose of by Burial Underround (hereafter referred to as underround burial ) - Tritiated water is mixed with a ce-based solidifyin aent or the like, and is buried within the confines of a concrete pit or the like, after safety has been ensured. (2) Items for Assess - The followin were established as items for assess so that all of the options listed in (1) could be compared side by side. (A) Basic Requires: items servin as rounds for determinin whether or not option is feasible - Technical Feasibility: technical feasibility of impleation, technical sophistication, whether or not track records exist - Reulatory Feasibility: compatibility with existin reulations (B) Potentially Restrictin Conditions: items which could potentially be restrictin conditions - Duration: duration of time required for treat (exploration, desin/construction, treat, dismantlin, monitorin, etc.) - Costs: costs required for treat (exploration, desin/construction, treat, dismantlin, monitorin, etc.) - Scale: area (land, sea) required for treat - Secondary Waste: whether or not secondary waste is produced, type and quantity - Radiation Exposure to Workers: whether workers would be exposed to excessive radiation in carryin out treat - Associated Conditions: other conditions which could potentially be restrictin 10

14 (3) Conditions Established for Comparative Assess - The followin three conditions were established as standardized conditions for comparin each option side by side. - These conditions were established for the sake of convenience in order to conduct the comparative study. Accordinly, the volume to be treated, treat capacity, and tritium concentration are subject to chane in liht of the period of impleation and the specific treat method. The followin conditions are not intended to be the conditions of the treat. Volume to be Treated: 0.8 m 3 This was set based on current total quantity of water in Unit 1 4 tanks (approximately 740,000 m 3, as of November 19, 2015) Treat Capacity: 400 m 3 /day This is the treat capacity which was established as a prerequisite in the separately impleed Verification of Technoloies for Contaminated Water Manae (Demonstration Project for Verification Tests of Tritium Separation Technoloies) Project. This was set such that the volume of increasin contaminated water (assessed value at that time) treat capacity. Tritium Concentration: permitted concentration or less From the perspective of standardizin the effects of radiation exposure, the tritium concentration was set at the upper limit of the permitted concentration which applies to each of the options. (In the event that the concentration does not reach the leally permitted amount, the treat should simply be carried out on said concentration, without performin enrich, etc.) Althouh reulations would not be met by settin only tritium at the leally permitted concentration, this condition was established simply for the purposes of the side-by-side comparison. - Other points to consider are as follows With respect to separation, since a separation factor of 100 or more was a basic require in the separately impleed Verification of Technoloies for Contaminated Water Manae (Demonstration Project for Verification Tests of Tritium Separation Technoloies) Project, a separation factor of 100 was also set as a prerequisite here. For all options, consideration is iven to reducin the radiation exposure of workers, and ensurin work safety in all processes from construction, to 11

15 treat, and dismantlin. The location where the treat is performed shall not be desinated. In the event that the treat is performed offsite from Fukushima Daiichi NPS, transport would be necessary, yet such transport was excluded from the comparative assess since it pertains equally to each option. For the leally permitted concentrations, please refer to the Notification for Vital Matters Pertainin to the Safety of the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station Reactor Facilities and Protection Aainst Specified Nuclear Fuel Materials. (4) Concrete Scenarios Established for Each Option (hereafter referred to as scenarios under assess ) - In establishin the scenarios under assess, the 11 options indicated in (1) were rendered as the basic scenarios and oranized in the followin manner. - Since the post-dilution vapor release scenario was determined to have no advantaes over the no pre-treat vapor release scenario based on the followin reasons, it was excluded from the present assess. The concentration () of tritium in the atmosphere beyond the exclusion zone does not depend on the concentration () in the tritiated water underoin evaporation treat, but depends on the release rate (Bq/s) If the volume to be treated per day is fixed, then the release rate (Bq/s) would be the same in both the post-dilution scenario and the no pre-treat scenario, so there would be no particular point in carryin out dilution. - For underround burial, the scenarios under assess were subdivided into deep burial below roundwater level (hereafter referred to as deep earth ) and shallow burial above roundwater level (hereafter referred to as shallow earth ). - For hydroen release, keepin in mind that hydroen is formed throuh the electrolysis of tritiated water, or the like, it must be noted that in the (post-separation) hydroen release scenario, dependin on the kind of separation technoloy, there are cases in which the depleted product (the product in which the concentration is reduced by means of separation) already contains hydroen, and in such cases hydroen release may be performed directly on the depleted product. Similarly, it must be noted that in the (post-separation) vapor release scenario, dependin on the kind of separation technoloy, there are cases in which the depleted product already contains water vapor, and in such cases 12

16 vapor release may be performed directly on the depleted product. - Based on the above, the scenarios were oranized into the followin 11 scenarios under assess. eosphere injection (no pre-treat (A1)/ post-dilution (B1)/ post-separation (C1)) offshore release (post-dilution (B2)/ post-separation (C2)) vapor release (no pre-treat (A3)/ post-separation (C3)) hydroen release (no pre-treat (A4)/ post-separation (C4)) underround burial (no pre-treat (deep earth) (A5a)/ no pre-treat (shallow earth) A5b)) - Furthermore, for these scenarios under assess, the concentration in the raw water and the volume of raw water were further subdivided into the followin five scenarios, accountin for a total of 55 (=11x5) scenarios under assess. (*) 1 a scenario in which concentration in raw water is 4.2, and raw water volume is 0.8 m 3 2 a scenario in which concentration in raw water is 0.5, and raw water volume is 0.8 m 3 3 a scenario in which concentration in raw water is 4.2, and raw water volume is 0.4 m 3 4 a scenario in which concentration in raw water is 0.5, and raw water volume is 0.4 m 3 5 a scenario of (*)The concentrations in raw water of 4.2 and 0.5 were adopted from the upper limit value and the lower limit value for tritiated water concentrations that were indicated in the Tritiated Water Task Force s Summary of Previous Discussions Reference Material No. 2 3 from the 12 th meetin of the Committee on Countermeasures for Contaminated Water Treat held on April 28, (5) Conceptual Desin for Each Scenario under Assess - Conceptual desins incorporatin the followin matters were impleed after concrete conditions based on the above conditions were established for each scenario under assess. - At that time, underround burial (Reference Materials 14 and 15) and eosphere injection (Reference Material 16) were discussed takin into account matters explained in the Task Force. 13

17 (Geosphere Injection) A1: (No Pre-Treat) Geosphere Injection - The tritiated water is transferred from the water storae tank to a samplin tank, and after the concentration per tank is measured, the water is sent by means of an injection pump to a deep subterranean reservoir (2,500 m deep), and then entrapped in the eosphere. B1: (Post-dilution) Geosphere Injection - The tritiated water is transferred from the water storae tank to a samplin tank, and after the concentration per tank is measured, the water is diluted with sea water until the desinated concentration (if the concentration in the raw water is 4.2 : dilution factor of 70; if it is 0.5 : dilution factor of approximately 8.3), and then the water is sent by means of an injection pump to a deep subterranean reservoir (2,500 m deep), and then entrapped in the eosphere. C1: (Post-separation) Geosphere Injection - The tritiated water is transferred from the separation processin (depleted product) water tank to a samplin tank, and after the concentration per tank is measured, the water is sent by means of an injection pump to a deep subterranean reservoir (2,500 m deep), and then entrapped in the eosphere. (Offshore Release) B2: (Post-dilution) Offshore Release - The tritiated water is transferred from the water storae tank to a samplin tank, and the concentration is measured. Thereafter, the water is mixed and diluted with sea water usin an intake water pump (if the concentration in the raw water is 4.2 : dilution factor of 70; if it is 0.5 : dilution factor of approximately 8.3), and dischared into the sea by pump. C2: (Post-separation) Offshore Release - The tritiated water is transferred from the separation processin (depleted product) water tank to a samplin tank, and after the concentration per tank is measured, the water is dischared into the sea by pump. (Vapor Release) A3: (No Pre-treat) Vapor Release 14

18 - The tritiated water is transferred from the water storae tank to a samplin tank, and the concentration per tank is measured. The tritiated water in the samplin tank is directly vaporized at , and the exhaust as is diluted with air (in order to prevent deterioration to the equip/machinery), and is released into the atmosphere at a heiht of 60 m above round level. C3: (Post-separation) Vapor Release - The tritiated water is transferred from the separation processin (depleted product) water tank to a samplin tank, and the concentration per tank is measured. The tritiated water in the samplin tank is directly vaporized at , and the exhaust as is diluted with air (in order to prevent deterioration to the equip/machinery), and is released into the atmosphere at a heiht of 60 m above round level. (Hydroen Release) A4: (No Pre-treat) Hydroen Release - The tritiated water is transferred from the water storae tank to a samplin tank, and the concentration per tank is measured. The tritiated water from the samplin tank is electrolyzed into hydroen and oxyen in an electrolyzer, and the produced hydroen as (which contains tritium as) is released into the atmosphere at a heiht of 20 m above round level. C4: (Post-separation) Hydroen Release - The tritiated water is transferred from the separation processin (depleted product) water tank to a samplin tank, and the concentration per tank is measured. The tritiated water from the samplin tank is electrolyzed into hydroen and oxyen in an electrolyzer, and the produced hydroen as (which contains tritium as) is released into the atmosphere at a heiht of 20 m above round level. (Underround Burial) A5a, A5b: (No Pre-treat) Underround Burial - Underround excavation is carried out to construct a concrete pit. In order to deter roundwater inflow, and tritiated water seepae, soil mixed with bentonite is laid around the periphery of the concrete pit (havin a thickness of 2 m if the concentration in the raw water is 4.2, or a thickness of 1 m if the concentration in the raw water is 0.5 ). 15

19 - A composition of tritiated water mixed toether with a ce-based solidifyin aent is poured into the finished concrete pit, to solidify toether with the concrete formation. - In order to deter the tritiated water from dissipatin due to evaporation while bein poured, a cover is installed on the top. - After solidification, a top slab for the concrete formation is poured, and soil mixed with bentonite (havin a thickness of 2 m if the concentration in the raw water is 4.2, or a thickness of 1 m if the concentration in the raw water is 0.5 ) is laid to further cover the installation. (6) Assess Results for Each Scenario under Assess - The assess results for each scenario under assess based on the conceptual desins listed in (5) are summarized in Appendix 2. - Note that the assess results are estimations based on approximations of the established hypothetical conditions, and they are not uarantees of the costs, etc., required for the treat. - For scenarios havin separation as the pre-treat, the results of the Demonstration Project for Verification Tests of Tritium Separation Technoloies (Appendix 3) impleed in the 2015 fiscal year were oin to be used in the assesss. However, as no technoloies were verified to be at a stae which could be immediately applied (Demonstration Project for Verification Tests of Tritium Separation Technoloies Summary and Assess (Appendix 4)), the technoloies are difficult to analyze at this point, so the fields reardin duration and cost have been left blank. - Other points to consider are as follows. Assesss have been carried out without desinatin the location where the treat is performed. The followin have not been taken into consideration in the assess results for duration: transport in the event that treat is performed offsite; simulations to assess environal impact, etc.; uncertainties in terms of securin resources and required personnel. The followin have not been taken into consideration in the assess results for costs: transport in the event that the treat is performed offsite; simulations to assess environal impact, etc.; uncertainties in terms of securin resources and required personnel; factors unique to the nuclear power plant site (additional personnel costs for work conducted under hih doses, 16

20 additional construction costs to make the nuclear facilities safe aainst earthquakes, etc.); costs to acquire land; fixed property taxes; costs for disposin of demolition waste, secondary waste, or construction spoil; costs for third party monitorin. 5. Conclusion This report is a compilation of the matters, includin reports from experts (Reference Materials 1 18), that were deliberated under the Tritiated Water Task Force over a total of 15 meetins from December 25, 2013 to May 27, 2016, and it discusses the contaminated water issues at Fukushima Daiichi NPS, in particular the handlin of tritiated water, from a technical perspective. It is hoped that this report will serve as basic data for future discussions. Also, since handlin tritiated water can larely influence rumors, it is hoped that future discussions about handlin tritiated water will be advanced in a comprehensive manner, touchin upon both technical perspectives, such as feasibility, economical efficiency, and duration, as well as social perspectives, such as damae caused by rumors. 17

21 As of May 27, 2016 Tritiated Water Task Force Member List Chief: Ichiro Yamamoto Committee Members: Hideki Kakiuchi Yoshihisa Takakura Hideo Tatsuzaki Hiroshi Tauchi Shunkichi Nonaka Takami Morita Toshihiko Yamanishi Tokuhiro Yamamoto Reulatory Authority: Toshihiro Imai Counselor/Emeritus Professor, Naoya University; Professor, Naoya University of Arts and Sciences (Member of Committee on Countermeasures for Contaminated Water Treat) Researcher, Depart of Radioecoloy, Institute for Environal Sciences Director, Tohoku Radioloical Science Center Director, Radiation Emerency Medicine Center, National Institute of Radioloical Sciences, National Institutes for Quantum and Radioloical Science and Technoloy Professor (Bioloical Sciences), Faculty of Science, Ibaraki University Manain Director, Co-op Fukushima Radioecoloy Group Leader, Radioecoloy Group, Research Center for Fisheries Oceanoraphy & Marine Ecosystem, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Aency Director, Depart of Blanket Systems Research, Rokkasho Fusion Institute, Fusion Enery Research and Develop Directorate, National Institutes for Quantum and Radioloical Science and Technoloy Director General, Nuclear Fuel Cycle Enineerin Laboratories, Japan Atomic Enery Aency (JAEA) (Member of Committee on Countermeasures for Contaminated Water Treat) Director, Office for accident measures of Fukushima-daiichi 18

22 Observers: Yuki Takeba Ryosuke Murayama Masato Usui Hirotsuu Fujiwara Masanori Imazu Jun Matsumoto Nobuyuki Kanno Nuclear power station, Nuclear Reulation Authority Director, Research and Technoloical Guidance Division, Resources Enhance Promotion Depart, Fisheries Aency Director for Decommissionin Technoloy Develop, Atomic Enery Division, Research and Develop Bureau, Ministry of Education, Culture, Sports, Science and Technoloy Director, International Nuclear Enery Cooperation Division, Disarma, Non-Proliferation and Science Depart, Ministry of Forein Affairs Director, International Research Institute for Nuclear Decommissionin General Manaer, Technoloical Stratey Group, Nuclear Damae Compensation and Decommissionin Facilitation Corporation Executive Vice President, Fukushima Daiichi Decontamination and Decommissionin Enineerin Company, Tokyo Electric Power Company Holdins, Inc. Director, Nuclear Power Safety Division, Risk Manae Depart, Fukushima Prefectural Govern 19

23 Tritiated Water Task Force Meetin Record December 25, 2013 (1st Meetin) Tritiated Water Task Force Protocol Electin the Task Force Chief Debates under the Committee on Countermeasures for Contaminated Water Treat, etc. (Explanation) Tritiated Water Task Force Approach (Discussion) January 15, 2014 (2nd Meetin) State of Contaminated Water Treat and Tritiated Water Storae at Fukushima Daiichi NPS Overview of Separation Technoloies and Underround Storae Multiple Options and Items for Assess February 7, 2014 (3rd Meetin) Items for Assess of Tritium (Beliefs about Environal Fate/Impact) February 27, 2014 (4th Meetin) Items for Assess of Tritium (Diffusion into Environ, etc.) March 13, 2014 (5th Meetin) Examples of Efforts Abroad March 26, 2014 (6th Meetin) Examples of Efforts Abroad April 9, 2014 (7th Meetin) Examples of Efforts Abroad April 24, 2014 (8th Meetin) Summary of Previous Discussions 20

24 July 9, 2014 (9th Meetin) Toward Option Assess (Discussion of Technical Feasibility of Options) October 24, 2014 (10th Meetin) Shallow Earth Disposal of Tritiated Water Selection Results from the Demonstration Project for Verification Tests of Tritium Separation Technoloies January 21, 2015 (11th Meetin) Optimal State of Communications with Stakeholders Additional Request for Proposals for the Demonstration Project for Verification Tests of Tritium Separation Technoloies June 5, 2015 (12th Meetin) Discussion of All Options for Treatin Tritiated Water December 4, 2015 (13th Meetin) Discussion of Conceptual Desins for All Options April 19, 2016 (14th Meetin) Assess of All Options (Scenarios Under Assess) for Handlin Tritiated Water Demonstration Project for Verification Tests of Tritium Separation Technoloies Tritiated Water Task Force Report Outline May 27, 2016 (15th Meetin) Tritiated Water Task Force Report 21

25 Appendix 1 Assess Results for All Options (Scenarios Under Assess) For Handlin Tritiated Water Office of the Committee on Countermeasures for Contaminated Water Treat May 27,

26 Removal of Non-tritium Isotopes Tritiated Water (1) Overview of Options <PRE-TREATMENT> < 前処理 > Treat Site of 処分方法 Primary 主な課題等 Tasks, etc. 処分先 Method Treat Dispose of by 地層中に Injection 注入廃棄 into Geosphere <OPTIONS> < 選択肢 > o Set parameters for underround injection (eosphere layer, injection speed, 地下注入方法 concentration, ( 地層 注入速度 濃度等 etc.) ) の設定 o地下注入後の拡散挙動の評価 Assess post-underround-injection diffusion behavior o拡散後の人体等への影響評価 Assess post-diffusion impact on humans, etc. o注入後の挙動のフォロー体制整備 Develop a system for followin post-injection behavior underround 地下 トリチウム以外の核種の除去 トリチウム水 Dilution 希釈 Isotopic Separation 同位体分離 Post- 希釈後の Dilution トリチウム水 Tritiated Water Increased 体積増大 Volume Reduced 低濃度化 Concentration Tritum Depleted 減損側 Water トリチウム水 体積減少 低濃度化 Reduced Volume Reduced Concentration Tritium Enriched 濃縮側トリチウム水 Water 体積減少 Reduced 高濃度化 Volume Increased Concentration Repeatin 同位体分離を isotopic separation 繰り返すこと enables further volume により 更なる reduction 減量化が可能 Release Offshore 海洋放出 Release as Vapor 水蒸気として into Atmosphere 大気放出 Reduce to Hydroen & 水素に還元し Release as 水素ガスとして Hydroen Gas 大気放出 into Atmosphere Solidfy or Gelify 固化 or& ゲル化 Dispose し 地下に of by Burial 埋設廃棄 Underround Dispose of Small 高濃度 小量の Amounts of トリチウム水を Hihly Concentrated Tritiated 廃棄 Water Store トリチウム水を Tritiated Water 貯蔵 Store Small Amounts 高濃度 小量の of Hihly トリチウム水を Concentrated Tritiated 貯蔵 Water o Set parameters for offshore release (release 海洋放出方法 site, release ( 放出先 放出量 濃度等 quantity, concentration, ) の設定 etc.) o海洋放出後の拡散挙動の評価 Assess post-offshore-release diffusion behavior o Assess post-diffusion impact on humans, etc. o拡散後の人体等への影響評価 Develop a system for followin post-offshorerelease 海洋放出後の挙動のフォロー体制整備 behavior o Set parameters for evaporation release 蒸発放出方法 (release speed, ( 放出速度 濃度等 concentration, ) の設定 etc.) o蒸発放出後の拡散挙動の評価 Assess post-evaporation-release diffusion behavior o拡散後の人体等への影響評価 Assess post-diffusion impact on humans, etc. o蒸発放出後の挙動のフォロー体制整備 Develop a system for followin postevaporation-release behavior 大気放出方法 o ( 放出速度 濃度等 ) の設定 concentration, etc.) 大気放出後の拡散挙動の評価 o 拡散後の人体等への影響評価 o Assess post-diffusion impact on humans, etc. o 大気放出後の挙動のフォロー体制整備 Set parameters for atmospheric release (release speed, Assess post-atmospheric-release diffusion behavior Develop a system for followin post-atmospheric-release behavior o Decide on burial site/burial method o埋設場所 埋設方法の設定 Assess behavior of dissolution from concrete, コンクリート等からの溶出挙動の評価 etc. o Assess post-dissolution impact on humans, etc. o溶出後の人体等への影響評価 Develop a system for followin post-dissolution 溶出後の挙動のフォロー体制整備 behavior o Select disposal method o廃棄方式の選定 Secure disposal site 廃棄場所の確保 o貯蔵することのリスク Assess storae risks o Establish method for safe, lon-term storae o安全に長期保管する手法の確立 Establish method for permanent manae o恒久的な管理手法の確立 Secure storae sites and tanks 保管場所及び貯槽の確保 o貯蔵することのリスク Assess storae risks o Select storae method o貯蔵方式の選定 Establish method for permanent manae o恒久的な管理手法の確立 Secure storae sites and tanks 保管場所及び貯槽の確保 大気 offshore 海洋 atmosphere underround 地下 equip 設備 1

27 Enrich Isotopic Separation Depletion (1) Overview of Options 選択肢の略称と成立性 Pre- 前処理 Treat 処分方法 Method Abbreviated 略称 Form Code 記号 Feasibility 成立性 Particular 成立性について特に留意すべき事項 Points to Consider Reardin Feasibility treat There are no pre-existin standards that can be applied 地層中に注入廃棄 Dispose of by Injection into Geosphere 地層注入 Geosphere Injection A1 適用される既存の基準無し (opinions exist that feasibility ( 安全性の確認が困難で成立性が低いとの意見あり is low as it is difficult to verify safety) ) 海洋放出 Release Offshore 海洋放出 Offshore Release A2 濃度限度 Difficult (60Bq/c) to imple を考慮すると 実現困難 considerin concentration limit (60Bq/c) None なし 水蒸気として大気放出 Release as Vapor into Atmosphere 水蒸気放出 Vapor Release A3 Reduce to Hydroen & Release as 水素に還元し 水素ガスとして大気放出 Hydroen Gas into Atmosphere 水素放出 Hydroen Release A4 Solidfy Gelify & Dispose of by Burial 固化 orゲル化し 地下に埋設廃棄 Underround 地下埋設 Underround Burial A5 トリチウム水を貯蔵 Store Tritiated Water 貯蔵 Storae A6 最終形にはならず あくまで一時的な措置 This is ultimately a temporary measure, not a permanent solution There are no pre-existin standards that can be applied 地層中に注入廃棄 Dispose of by Injection into Geosphere 希釈後 地層注入 Post-Dilution B1 適用される既存の基準無し (opinions exist that feasibility ( 安全性の確認が困難で成立性が低いとの意見あり is low as it is difficult to verify safety) ) Geosphere Injection 海洋放出希釈後 海洋放出 Post-Dilution Release Offshore B2 効率的な希釈方法等についても要検討 It is necessary to consider effective dilution method Offshore Release Dilution 希釈 Post-Dilution Vapor Release 水蒸気として大気放出 Release as Vapor into Atmosphere 希釈後 水蒸気放出 B3 Reduce to Hydroen & Release as Post-Dilution 水素に還元し 水素ガスとして大気放出希釈後 水素放出 B4 希釈により取扱い水量が増大するため 処理が困難化 Treat becomes more challenin since the volume of water handled increases from dilution Hydroen Gas into Atmosphere Hydroen Release Solidfy or Gelify & Dispose of by Burial Post-Dilution Treat and manae become more challenin since the volume of water handled 固化 orゲル化し 地下に埋設廃棄希釈後 地下埋設 B5 希釈により取扱い水量が増大するため 処理 管理が困難化 Underround Underround Burial increases from dilution Treat and manae become more challenin since the volume of water handled トリチウム水を貯蔵 Store Tritiated Water 希釈後 貯蔵 Post-Dilution Storae B6 希釈により取扱い水量が増大するため 処理 管理が困難化 increases from dilution Post-Separation There are no pre-existin standards that can be applied 地層中に注入廃棄 Dispose of by Injection into Geosphere 分離後 地層注入 C1 適用される既存の基準無し (opinions exist that feasibility ( is 安全性の確認が困難で成立性が低いとの意見あり low as it is difficult to verify safety) ) Geosphere Injection 同位体分離 減損 濃縮 Post-Separation Offshore Release 海洋放出 Release Offshore 分離後 海洋放出 C2 水蒸気として大気放出 Release as Vapor into Atmosphere Post-Separation 分離後 水蒸気放出 C3 Vapor Release Reduce to Hydroen & Release as Post-Separation 水素に還元し 水素ガスとして大気放出 Hydroen Gas into Atmosphere 分離後 水素放出 C4 Hydroen Release Solidfy Gelify & Dispose of by Burial Post-Separation There is no merit to separation as lon-term manae would also be necessary after 固化 orゲル化し 地下に埋設廃棄分離後 地下埋設 C5 分離後にも長期管理が必要となり 分離のメリットなし Underround Underround Burial separation Post-Separation There is no merit to separation as lon-term manae would also be necessary after トリチウム水を貯蔵 Store Tritiated Water 分離後 貯蔵 C6 分離後にも長期管理が必要となり 分離のメリットなし Storae separation Dispose of Small Amounts of Hihly 高濃度 少量のトリチウム水を廃棄 Concentrated Tritiated Water 濃縮廃棄 Enrich Disposal C'a 廃棄方法を要検討 It is necessary to consider disposal method Store Small Amounts of Hihly This is ultimately a temporary measure, not a permanent solution (it is necessary to also 高濃度 少量のトリチウム水を貯蔵 Concentrated Tritiated Water 濃縮貯蔵 Enrich Storae C'b 最終形にはならず あくまで一時的な措置 consider methods for final disposal/utilization) ( 最終的な処理 活用方法についても要検討 ) 2

28 (2) Items for Assess The followin items for assess were established in order to conduct a side-by-side comparison of each option. Proposed Items for Assess Basic Requires Description Items servin as rounds for determinin whether or not option is feasible Technical Feasibility Technical feasibility of impleation, technical sophistication, whether or not track records exist Reulatory Feasibility Potentially Restrictin Conditions Duration Costs Scale Compatibility with existin reulations Items which could potentially be restrictin conditions Duration of time required for treat (exploration, desin/construction, treat, dismantlin, monitorin, etc.) Costs required for treat (exploration, desin/construction, treat, dismantlin, monitorin, etc.) Area (land, sea) required for treat Secondary Waste Radiation Exposure of Workers Whether or not secondary waste is produced, type and quantity Whether there would be excessive radiation exposure to workers in carryin out treat Associated Conditions Other conditions which could potentially be restrictin 3

29 (3) Conditions Established for Comparative Assess The followin 3 conditions were established as standardized conditions for comparin each option side by side. *These conditions were established for the sake of convenience in order to conduct the comparative study. The volume to be treated, treat capacity, and concentration to be treated are subject to chane in liht of the period of impleation and the specific treat method. The followin conditions are not intended to be the conditions of the treat. 1. Volume to be treated: 0.8 m 3 This was set based on current total quantity of water in Unit 1 4 tanks (approximately 740,000, as of November 19, 2015). 2. Treat capacity: 400m 3 /day This is the treat capacity which was established as a prerequisite in the separately impleed Verification of Technoloies for Contaminated Water Manae (Demonstration Project for Verification Tests of Tritium Separation Technoloies) Project. *This was set such that the volume of increasin contaminated water (assessed value at that time) treat capacity. 3. Tritium concentration: permitted concentration or less In order to standardize the effects of radiation exposure, the concentration to be treated was set at the upper limit of the permitted concentration which applies to each of the options. (In the event that the concentration does not reach the leally permitted amount, the treat should simply be carried out on said concentration, without performin enrich, etc.) Althouh reulations would not be met by settin only tritium at the leally permitted concentration, this condition was established simply for the purposes of the side-by-side comparison. Other Points to Consider With respect to separation, since a separation factor of 100 or more was a basic require in the separately impleed Verification of Technoloies for Contaminated Water Manae (Demonstration Project for Verification Tests of Tritium Separation Technoloies) Project (meanin that the amount of radioactivity in the depleted product would be 1/100 or less of the oriinal tritiated water), a separation factor of 100 was also set as a prerequisite for this assess. For all options consideration is iven to reducin the radiation exposure of workers, and ensurin work safety in all processes from construction, to treat, and dismantlin. The location where the treat is performed shall not be desinated. In the event that the treat is performed offsite, transport would be necessary, yet such transport was excluded from the comparative assess since it pertains equally to each option. For the leally permitted concentrations, please refer to the Notification for Vital Matters Pertainin to the Safety of the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station Reactor Facilities and Protection Aainst Specified Nuclear Fuel Materials. 4

30 (4) Concrete Scenarios (Scenarios Under Assess) Established for Each Option The followin 11 carefully-considered options were established as the basic scenarios to undero assess. eosphere injection (no pre-treat/ post-dilution/ post-separation) offshore release (post-dilution/ post-separation) vapor release (no pre-treat/ post-dilution/ post-separation) hydroen release (no pre-treat/ post-separation) underround burial (no pre-treat) Since the post-dilution vapor release scenario was determined to have no advantaes over the no pre-treat vapor release scenario based on the followin reasons, it was excluded from the present assess. The concentration () of tritium in the atmosphere beyond the exclusion zone does not depend on the concentration () in tritiated water which would undero evaporation treat, but depends on the release rate (Bq/s). As is described hereafter, if the volume to be treated per day is fixed, then the release rate (Bq/s) would be the same in both the post dilution scenario and the no pre-treat scenario, so there would be no particular point in carryin out dilution. For underround burial, the scenarios under assess were subdivided into: 1 Deep burial below roundwater level (hereafter referred to as deep earth ) 2 Shallow burial above roundwater level (hereafter referred to as shallow earth ) 5

31 (4) Concrete Scenarios (Scenarios Under Assess) Established for Each Option For hydroen release, keepin in mind that hydroen is formed throuh the electrolysis of tritiated water, or the like, it must be noted that in the (post-separation) hydroen release scenario, dependin on the kind of separation technoloy (CECE process, etc.), there are cases in which the depleted product already contains hydroen, and in such cases hydroen release may be performed directly on the depleted product. Similarly, it must be noted that in the (post-separation) vapor release scenario, dependin on the kind of separation technoloy, there are cases in which the depleted product already contains water vapor, and in such cases vapor release may be performed directly on the depleted product. For the aboveioned 11 scenarios under assess, the concentration in the raw water and the volume of raw water were further subdivided into the followin five scenarios, accountin for a total of 55 scenarios under assess. 1 a scenario in which concentration in raw water is 4.2, and raw water volume is 0.8 m 3 2 a scenario in which concentration in raw water is 0.5, and raw water volume is 0.8 m 3 3 a scenario in which concentration in raw water is 4.2, and raw water volume is 0.4 m 3 4 a scenario in which concentration in raw water is 0.5, and raw water volume is 0.4 m 3 5 a scenario of 3+4 *The concentrations in raw water of 4.2 and 0.5 were adopted from the upper limit value and the lower limit value for tritiated water concentrations that were indicated in the Tritiated Water Task Force s Summary of Previous Discussions (Reference Material No. 2-3 from the 12 th meetin of the Committee on Countermeasures for Contaminated Water Treat on 4/28/2014). A table listin the scenarios under assess reflectin the above appears on the next pae. 6

32 (4) Concrete Scenarios (Scenarios Under Assess) Established for Each Option Overview of Options at 8 th Meetin Scenarios Under Assess in this Study Code Treat Method Pretreat Code Treat Method Pretreat A1 none A1 1 5 none B1 eosphere injection dilution B1 1 5 eosphere injection dilution C1 separation C1 1 5 separation B2 C2 offshore release dilution separation B2 1 5 C2 1 5 offshore release dilution separation A3 B3 vapor release none dilution A3 1 5 C3 1 5 vapor release none separation C3 A4 C4 A5 hydroen release underround burial separation none separation none A4 1 5 C4 1 5 A5a 1 5 A5b 1 5 hydroen release underround burial (deep earth) underround burial (shallow earth) none separation none none *For 1 5, refer to previous section 7

33 (5) Conceptual Desin for Each Scenario Under Assess (Same for Each Option) The method for measurin the concentration in the raw tritiated water was established as per the followin diaram, and is the same for each option. tank of tritiated water (0.8 m 3 ) aitator water level (water volume) measure L tank tritiated water 400m 3 sample measures (1 time/ batch) of tritium concentration in the water pump onto various treat processes 8

34 (5) Conceptual Desin for Each Scenario Under Assess (Geosphere Injection) Same for All Geosphere Injection Options (A1, B1, C1) Construction method & injection depth: established referencin CCS (carbon capture & storae) demonstration examples * Althouh there are other examples, such as an example of shallow earth injection at Hanford (USA), it is thouht that a shallow earth injection would not be suitable in Japan where the roundwater level is shallow, so CCS examples are bein referenced. Reduction pace of raw tritiated water injection operation: 400m 3 /day A1: (No Pre-treat) Geosphere Injection Concentration: As there is no relevant leally permitted concentration, injection performed without set restriction, for the sake of convenience. Volume treated: As there is no pre-treat, 0.8 m 3 The tritiated water is transferred from the water storae tank to a samplin tank, and after the concentration per tank is measured, the water is sent by means of an injection pump to a deep subterranean reservoir (2,500m deep), and then entrapped in the eosphere. B1: (Post-dilution) Geosphere Injection Concentration: Usin 60,000 as a reference value, which is the permitted concentration for radioactive material comin from a dischare port, injection performed after dilution until a concentration of 60,000 Volume treated: The volume treated is increased accordin to the dilution rate for ensurin the above concentration. The tritiated water is transferred from the water storae tank to a samplin tank, and after the concentration per tank is measured, the water is diluted with sea water until the desinated concentration (if the concentration in the raw water is 4.2 : dilution factor of 70; if it is 0.5 : dilution factor of approximately 8.3), and then the water is sent by means of an injection pump to a deep subterranean reservoir (2,500m deep), and then entrapped in the eosphere. C1: (Post-separation) Geosphere Injection Concentration: Injection performed at the concentration of the depleted product which was separated with a separation factor of 100. Volume treated: Assumin that the quantity of the post-separation enriched product can be disrearded (the quantity of the depleted product unchanin), the volume treated shall be 0.8 m 3. State of tritiated water to be treated: The post-separation depleted product shall be in liquid form. The tritiated water is transferred from the separation processin (depleted product) water tank to a samplin tank, and after the concentration per tank is measured, the water is sent by means of an injection pump to a deep subterranean reservoir (2,500m deep), and then entrapped in the eosphere. *These conditions were established for the sake of convenience in order to conduct the comparative study, and are not intended to be the actual conditions of the treat. 9

35 (5) Conceptual Desin for Each Scenario Under Assess (Geosphere Injection) Monitorin Method A1: (No Pre-treat) Geosphere Injection measure of concentration in raw water (same for all) Reulation: The concentration of the radioactive material in the wastewater comin from the wastewater outlet or the wastewater monitorin equip must not exceed the concentration limit declared by the Nuclear Reulation Authority eosphere injection B1: (Post-dilution) Geosphere Injection measure of concentration in raw water (same for all) diluted water flowmeter C1: (Post-separation) Geosphere Injection flowmeter eosphere injection Dilute accordin to the concentration in the raw water until concentration is at or below the limit water of separated depleted product measure of concentration in raw water (same for all) Verify that concentration is at or below the limit eosphere injection 10

36 (5) Conceptual Desin for Each Scenario Under Assess (Geosphere Injection) Conceptual Diaram: (No Pre-treat) Geosphere Injection Example injection pump (work area: 10m X 10m) approx. 10m approx. 20m samplin tank (for monitorin raw water) injection well shieldin layer (mudstone, etc.) reservoir (sandstone, etc.) tritium entrapped in eosphere 11

37 (5) Conceptual Desin for Each Scenario Under Assess (Offshore Release) Same for All Offshore Release Options (B2, C2) Reduction pace of raw tritiated water rated release operation: 400m 3 /day B2: (Post-dilution) Offshore Release Concentration: Release performed after dilution until a concentration of 60,000, which is the permitted concentration for radioactive material comin from a dischare port. Volume treated: The volume treated is increased accordin to the dilution rate for ensurin the above concentration. The tritiated water is transferred from the water storae tank to a samplin tank, and the concentration is measured. Thereafter, the water is mixed and diluted with sea water usin an intake water pump (if the concentration in the raw water is 4.2 : dilution factor of 70; if it is 0.5 : dilution factor of approximately 8.3), and dischared into the sea by pump. C2: (Post-separation) Offshore Release Concentration: Release performed directly since the concentration of the depleted product which was separated with a separation factor of 100 is less than 60,000. Volume treated: Assumin that the quantity of the post-separation enriched product can be disrearded (the quantity of the depleted product unchanin), the volume treated shall be 0.8 m 3. State of tritiated water to be treated: The post-separation depleted product shall be in liquid form. The tritiated water is transferred from the separation processin (depleted product) water tank to a samplin tank, and after the concentration per tank is measured, the water is dischared into the sea by pump. *These conditions were established for the sake of convenience in order to conduct the comparative study, and are not intended to be the actual conditions of the treat. 12

38 (5) Conceptual Desin for Each Scenario Under Assess (Offshore Release) Monitorin Method B2: (Post-dilution) Offshore Release Reulation: The concentration of the radioactive material in the wastewater comin from the wastewater outlet or the wastewater monitorin equip must not exceed the concentration limit declared by the Nuclear Reulation Authority measure of concentration in raw water (same for all) flowmeter diluted water offshore release flowmeter Dilute accordin to the concentration in the raw water until concentration is at or below the limit C2: (Post-separation) Offshore Release water of separated depleted product measure of concentration in raw water (same for all) offshore release Verify that concentration is at or below the limit 13

39 (5) Conceptual Desin for Each Scenario Under Assess (Offshore Release) Conceptual Diaram: (Post-dilution) Offshore Release Example samplin tank (for monitorin raw water) approx. dischare pump (for sendin mixed water to dischare port) approx. 20m approx. 1 Km approx. 12m approx. 10m approx. 1 Km intake water pump intake water pit dischare port * Must be devised such that dischared water is not directly taken in aain. Here a measure is employed in which there is sufficient distance between the position of the intake water pit and the position of the dischare port. In terms of other measures, it is possible to conceive of a measure in which a divider, such as a quay wall, is used between the intake water pit and the dischare port, or a measure in which the dischare port is positioned further offshore. 14

40 (5) Conceptual Desin for Each Scenario Under Assess (Vapor Release) Same for All Vapor Release Options (A3, C3) Reduction pace of raw tritiated water release operation: 400m 3 /day Concentration: The concentration must be 5 or less, which is the permitted concentration for radioactive material in the atmosphere beyond the exclusion zone. Condensation (returnin to liquid form) must not occur beyond the exhaust pipe outlet. A3: (No Pre-treat) Vapor Release Exhaust pipe heiht: The exhaust pipe heiht which enables the tritium concentration in the atmosphere beyond the exclusion zone to be 5 or less was compared with the common exhaust pipe heiht utilized when there is direct contact with combustion equip, and the taller exhaust pipe heiht (60m above round level) was adopted. Volume treated: As there is no pre-treat, 0.8 m 3 The tritiated water is transferred from the water storae tank to a samplin tank, and the concentration per tank is measured. The tritiated water in the samplin tank is directly vaporized at , and the exhaust as is diluted with air (in order to prevent deterioration to the equip/machinery), and is released into the atmosphere at a heiht of 60m above round level. C3: (Post-separation) Vapor Release Exhaust pipe heiht: Same as heiht in no pre-treat scenario Volume treated: Assumin that the quantity of the post-separation enriched product can be disrearded (the quantity of the depleted product unchanin), the volume treated shall be 0.8 m 3. State of tritiated water to be treated: The post-separation depleted product shall be in liquid form. The tritiated water is transferred from the separation processin (depleted product) water tank to a samplin tank, and the concentration per tank is measured. The tritiated water in the samplin tank is directly vaporized at , and the exhaust as is diluted with air (in order to prevent deterioration to the equip/machinery), and is released into the atmosphere at a heiht of 60m above round level. *These conditions were established for the sake of convenience in order to conduct the comparative study, and are not intended to be the actual conditions of the treat. 15

41 (5) Conceptual Desin for Each Scenario Under Assess (Vapor Release) Monitorin Method A3: (No Pre-treat) Vapor Release C3: (Post-separation) Vapor Release Reulation: The concentration of the radioactive material in the exhaust air comin from the exhaust outlet or the exhaust air monitorin equip must be monitored such that the concentration of the radioactive material in the atmosphere beyond the exclusion zone does not exceed the concentration limit declared by the Nuclear Reulation Authority exhaust pipe sample measures (1 time/day) of tritium concentration in exhaust air measure of concentration in raw water (same for all) vaporizer due to hih temperature, measure to be conducted after coolin and condensin the release rate (Bq/s) is calculated from the concentration in the raw water, and the heiht of the exhaust pipe and meteoroloical conditions are used to assess if the concentration will be at or below the limit for the concentration in the atmosphere beyond the exclusion zone 16

42 (5) Conceptual Desin for Each Scenario Under Assess (Vapor Release) Conceptual Diaram: (No Pre-Treat) Vapor Release Example exhaust pipe (to release tritiated water vapor) blower room (blower and compressor equip for combustion, heat reduction and dilution) 60m incinerator control annex pipin rack approx. approx. samplin tank (for monitorin raw water) 17

43 (5) Conceptual Desin for Each Scenario Under Assess (Hydroen Release) Same for All Hydroen Release Options (A4, C4) Reduction pace of raw tritiated water release operation: 400m 3 /day Concentration: The concentration must be 70,000 or less, which is the permitted concentration for radioactive material in the atmosphere beyond the exclusion zone. At the exhaust pipe outlet, the concentration must be below the hydroen-combustible concentration A4: (No Pre-treat) Hydroen Release Exhaust pipe heiht: The exhaust pipe heiht which enables the tritium concentration in the atmosphere beyond the exclusion zone to be 70,000 or less was compared with the exhaust pipe heiht for ensurin safety from an enineerin standpoint, and the taller exhaust pipe heiht (20m above round level) was adopted. Volume treated: As there is no pre-treat, 0.8 m 3 The tritiated water is transferred from the water storae tank to a samplin tank, and the concentration per tank is measured. The tritiated water from the samplin tank is electrolyzed into hydroen and oxyen in an electrolyzer, and the produced hydroen as (which contains tritium as) is released into the atmosphere at a heiht of 20 m above round level. C4: (Post-separation) Hydroen Release Exhaust pipe heiht: Same as heiht in no pre-treat scenario Volume treated: Assumin that the quantity of the post-separation enriched product can be disrearded (the quantity of the depleted product unchanin), the volume treated shall be 0.8 m 3. State of tritiated water to be treated: The post-separation depleted product shall be in liquid form. The tritiated water is transferred from the separation processin (depleted product) water tank to a samplin tank, and the concentration per tank is measured. The tritiated water from the samplin tank is electrolyzed into hydroen and oxyen in an electrolyzer, and the produced hydroen as (which contains tritium as) is released into the atmosphere at a heiht of 20 m above round level. *These conditions were established for the sake of convenience in order to conduct the comparative study, and are not intended to be the actual conditions of the treat. 18

44 (5) Conceptual Desin for Each Scenario Under Assess (Hydroen Release) Monitorin Method A4: (No Pre-treat) Hydroen Release C4: (Post-separation) Hydroen Release Reulation: The concentration of the radioactive material in the exhaust air comin from the exhaust outlet or the exhaust air monitorin equip must be monitored such that the concentration of the radioactive material in the atmosphere beyond the exclusion zone does not exceed the concentration limit declared by the Nuclear Reulation Authority exhaust pipe sample measures (1 time/day) of tritium concentration in exhaust air measure of concentration in raw water (same for all) electrolysis equip the release rate (Bq/s) is calculated from the concentration in the raw water, and the heiht of the exhaust pipe and the meteoroloical conditions are used to assess if the concentration will be at or below the limit for the concentration in the atmosphere beyond the exclusion zone 19

45 power source (5) Conceptual Desin for Each Scenario Under Assess (Hydroen Release) Conceptual Diaram: (No Pre-treat) Hydroen Release Example as-liquid separator as-liquid separator presamplin tank treat (for monitorin raw water) feed tank bipolar-type water electrolyzer (separation/production of H 2 & O 2 by means of electrolysis) diaphram 20 m heiht dilution blower O 2 exhaust pipe H 2 exhaust pipe 20

46 (5) Conceptual Desin for Each Scenario Under Assess (Underround Burial) A5: (No Pre-treat) Underround Burial Reduction pace of raw tritiated water burial operation: 400 m 3 /day Construction method: Usin a concrete disposal pit as the foundation, tritiated water and a ce-based solidifyin aent are mixed toether and poured directly within the confines of the pit, becomin interally solidified with the installation. (*1) Thickness of bentonite layer: the thickness of the man-made barrier (bentonite layer) is calculated such that the tritium concentration in any water seepin throuh the barrier becomes 60,000, which is the permitted concentration for radioactive material in water. Example: approximately 2m (if the concentration in the raw water is 4.2 ) or approximately 1m (if the concentration in the raw water is 0.5 ) Volume treated: As there is no pre-treat, 0.8 m 3 Underround excavation is carried out to construct the concrete pit. In order to deter roundwater inflow, or tritiated water seepae, soil mixed with bentonite is laid around the periphery of the concrete pit (havin a thickness of 2m if the concentration in the raw water is 4.2, or a thickness of 1m if the concentration in the raw water is 0.5 ). A composition of tritiated water mixed toether with a ce-based solidifyin aent is poured into the finished concrete pit, to solidify toether with the concrete formation. In order to deter the tritiated water from dissipatin due to evaporation while bein poured, a cover is installed on the top. After solidification, a top slab for the concrete formation is poured, and the soil mixed with bentonite (havin a thickness of 2m if the concentration in the raw water is 4.2, or a thickness of 1m if the concentration in the raw water is 0.5 ) is laid to further cover the installation. (*1) From the 10 th Tritiated Water Task Force Meetin Reference Material No. 1 Study Pertainin to Shallow Earth Disposal of Tritiated Water *These conditions were established for the sake of convenience in order to conduct the comparative study, and are not intended to be the actual conditions of the treat. 21

47 (5) Conceptual Desin for Each Scenario Under Assess (Underround Burial) Monitorin Method A5: (No Pre-treat) Underround Burial In compliance with the Rule for Disposal of Cateory 2 Waste Disposal of Nuclear Fuel Material or Material Contaminated with Nuclear Fuel Material measure of concentration in raw water (same for all) sample measures of tritium concentration in atmosphere to be continuously monitored burial operation sample measures of tritium concentration in roundwater to be taken 1 time/month & after burial operation direction of roundwater flow concrete pit (inlaid with ce mixed w/ tritiated water) 22

48 (5) Conceptual Desin for Each Scenario Under Assess (Underround Burial) Conceptual Diaram: Example of Deep Burial Below Groundwater Level roundwater level round surface roundwater soil layer mixed with bentonite (soil layer with low water permeability) (to deter diffusion of tritiated water) concrete pit (tritiated water solidified into concrete) required area: 285,000m 2 round surface roundwater level concrete pit Scenario where installation is below roundwater level overlaid soil roundwater level soil layer with low water permeability (soil mixed w. bentonite) cross-sectional view soil mixed with bentonite (soil layer with low water permeability) Scenario where installation is above roundwater level soil layer with low water permeability (soil mixed w. bentonite) Diaram on Riht: From the 10 th Tritiated Water Task Force Meetin Reference Material No. 1 Study Pertainin to Shallow Earth Disposal of Tritiated Water overlaid soil seepae control sheet roundwater level 23