Generic Aspects for Dismantling Preparation of INPP Reactor Facilities. Aleksej Merežnikov, Ignalina NPP, July 2014

Transcription

1 Generic Aspects for Dismantling Preparation of INPP Reactor Facilities Aleksej Merežnikov, Ignalina NPP, July 2014

2 Agenda INTRODUCTION REGULATORY FRAMEWORK RBMK-1500 FEATURES GENERAL APROACH STATUS AND RESULTS 2

3 Introduction The key INPP function has been changed to «decommissioning organization» after Unit 2 Reactor Final Shutdown INPP set up a team to implement the reactor D&D project (UP01). Project Objectives: to prepare the dismantling technologies for structures and equipment from INPP Units reactor shafts. to dismantle the reactor structures and equipment from INPP Unit 1 reactor shafts applying the already developed technologies.

4 Regulatory Framework (1) International Conventions: Nuclear Safety Convention (ratified in 1995) Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management (ratified in 2003) Laws: on Nuclear Energy; on Nuclear Safety; on the Management of Radioactive Waste; on Radiation Protection; on Decommissioning of State Enterprise Ignalina NPP Unit 1 (2000) Governmental Resolutions: on the State Enterprise Ignalina NPP Unit 1 Decommissioning Method (2002); on the Radioactive Waste Management Strategy (2008), etc. 4

5 Regulatory Framework (2) State Nuclear Power Safety Inspectorate (VATESI) requirements and rules ( issued more than 40 valid documents): including Requirements for Decommissioning of Nuclear Facilities, P ; Requirements on Radioactive Waste Pre-Disposal Management at the Nuclear Power Plant, BSR ; Requirements on Disposal of Radioactive Short-Lived Low and Intermediate-Level Waste. P ; Requirements on Disposal of Radioactive Very Low Level Waste. P ; Standard Requirements on Radioactive Waste Acceptability for Disposal in the Near Surface Repository. P ; Nuclear Safety Requirements on Modification Categories and Modifications Procedures of the Nuclear Facility BSR OTHER STACKHOLDERS (such as Owner, specialized Agencies, Donors) introduce additional requirements and regulations. 5

6 RBMK-1500 Features (1) Parameter Value Coolant water (steam-water mixture) Heat cycle configuration single circuit Power, MW: thermal (design) 4800 thermal (actual) 4200 Graphite stack dimensions, m: 2488 graphite columns ~ 1760 t per Unit height 8 diameter ~ 11.8 Lattice pitch, m 0.25 x 0.25 Number of channels: fuel 1661 control and shutdown system 235 reflector-cooling 156 uranium dioxide (fuel enrichment for 235U, 2 Fuel % to 2.8 % with erbium as burnable neutron absorber ) Pressures, (kgf/cm 2 ): at separator drum (67) at pressure header (86.6) Coolant flow rate through reactor, m 3 /s (m 3 /h) ( ) Steam produced in reactor, kg/s (t/h) ( ) 6

7 RBMK-1500 Features (2) Height: 8 m Diameter ~ 14 m Weight: 1760 t per unit Bugey-1 Height: 9 m Diameter m Weight: 2060 tonnes Anthony Banford National Nuclear Laboratory UK Michael Grave Doosan Babcock part of Doosan Power Systems Ltd Christian Glorennec (EDF) France INPP

8 RBMK-1500 Features (3)

9 RBMK-1500 Features (4) WELL DEVELOPED AND SIMPLE METHODS were applied (from heavy industry experience and early military facilities). BUT Decommissioning Requirements were not applied for the operational design. In particular, «Access to Reactor Areas»; «Decommissioning Waste Management» «Decommissioning Costing» are not the «strong» points at the moment. EMPTY REACTOR SHAFT

10 RBMK-1500 Features (5) ASSEMBLING OF REACTOR UPPER GUIDES EQUIPMENT ASSEMBLING IN CENTRAL HALL 10

11 RBMK-1500 Features (6) (Central Hall): First CPS channel transferring for the radiological surveys Compartments with reactor communications 11

12 General Approach (1): Decommissioning Strategy Reduce the nuclear risk: Units defueling and provision of safe interim storage for spent fuel (beyond the project scope - but has impact on planning/costs allocation) Comply with radiation protection constraints: Built into the project scope Reduce environmental risks: Built into the project scope Proceed with Immediate Dismantling: Ensuring fuel safety (beyond the project scope, but interfaces with the project schedule, especially for Unit 2) Ensuring needed waste management routes and interim storage/disposal facilities are available (beyond the project scope - but numerous interfaces with project schedule)

13 General Approach (2) in each certain case: permissions and licensing by state institutions engineering studies radiological surveys development of the D&D design documentation preparatory works dismantling and decontamination Identification Data Collection Material Inventory Dimensions Weight Etc. Identification Dose Rates Activation Contamination Radiological Inventory Preliminary Waste Classification Etc. D&D Technologies Conjunction with Radwaste Projects Safety Justification Environmental Impact Assessment Etc. Preparation of Works Areas Preparation of Size Reduction, Sorting, Packaging Areas Commissioning of New Systems, Tools, Training Etc. Cutting Size Reduction Insitu Radioactivity Control Sorting Decontamination if Reasonable. Radwaste Routing Safety Measures Etc : «Engineering on Dismantling of Units 1&2 Structures from Reactor Shafts» (UP01 Project) Changes of INPP Decommissioning MegaProject. The 2101 (Unit1)/2102 (Unit 2) Projects «Dismantling of Reactor Facility» completion

14 General Approach (3): D&D Area Splitting R1 & R2 (2190 t) maintenance experience and well recognized tools available access limited set of materials with low/no irradiation R3 (10910 t) minor experience, difficult accesses variety of materials (minerals fillings, graphite, steels) in-core irradiation, contamination in periphery no commercial available solution for graphite treatment 14

15 General Approach (4): Strategic D&D Sequence Project Charter (Description) was issued in Strategic D&D sequence was agreed with the Owner and Nuclear Regulator in

16 General Approach (5): Radwaste Classification OLD CLASSIFICATION msv/h *) 0.3 msv/h *) 10 msv/h *) *) 10 cm from waste surface Industrial waste Group 1 Group 2 Group Surface dose rate, msv/h Cleared waste Clearance levels VLLW LLW - SL ILW - SL Class A Class B Class C 0.5 msv/h 2 msv/h Class D LLW - LL ILW - LL NEW CLASSIFICATION Class E 10 msv/h Short - lived radwaste Long - lived radwaste Radwaste Routes * depending on associated WAC 16

17 General Approach (6): «No Waste Routes No Dismantling» D E Under construction B C D E A 0 Under construction D Under construction F F B C A 0 Tendering shortly E F

18 STATUS AND RESULTS: R1 + R2 (1) Engineering studies for dismantling from R1 and R2 areas - completed in July «Update of R1 and R2 Engineering Inventory Database» 100 % (March 2014). Radiological surveys for R1 and R2 areas. «Scoping Radiological Surveys» were completed in September «Characterization Radiological surveys» were completed in May it is ~ 85 % of total needs «Development of scaling factors for DTM (difficult to measure) nuclides for R1 and R2 areas» remains uncompleted one. The planned completion date 2016.

19 STATUS AND RESULTS: R1 + R2 (2) 19

20 STATUS AND RESULTS: R1 + R2 (3) Design activities on R1, R2 Areas (Unit 1) ongoing: 2014 target 60 %, target completion date - May 2017, target date to obtain the dismantling permission The licensing, permissions - VATESI permissions are received in each certain case. Practical designing

21 STATUS AND RESULTS: R1 + R2 (4) Preparatory works in R1 and R2 areas (Unit 1) on-going. For example, the preparatory works in R1 and R2 areas (Unit 1) in contain some isolation works to plug in the upper guides (instead of RBM-K5 assembly 25-26), and lower communications (instead of RBM-K U-elbows). These Primary Circuit s isolations works supports the optimal initial conditions for Fuel Channels dismantling. 21

22 STATUS AND RESULTS: R3 (5) Engineering studies for dismantling from R3 area - «Update of R3 Engineering Inventory Database» 100 %. Project team had assessed previously obtained results of reactor surveys and the preparatory works for period. The final version of report was issued in July Radiological surveys for R3 area. ~ 60 % (on the basis of completed 100 % sampling under 2101 scope). The planned completion date The additional radiological surveys concerning the properties of irradiated stainless steels (Unit 1) items The set of needed improvements was specified with regard to the implementation of the radioactive waste facilities. Design Activities on R3 Area (Unit 1) planning.

23 STATUS AND RESULTS: R3 (6) 23

24 STATUS AND RESULTS: Project 2101 Critical Path (7) 24

25 Examples: Sampling and Characterization Surveys Example: Sampling and Characterization surveys for Steam-Water Pipelines (R1 area) Identification of typical and reasonable locations Cutting of samples Plugging of sampled pipelines Steam-Water Lines Samples Doserate measurements Spectrometric measurements Beta-contamination levels by smear technique Reporting sample Samples from other R1 & R2 locations and items (excluding DTM (difficult to measure) nuclides and scaling factors) INPP Laboratory 25

26 Example: Removal and Surveys of 16 Fuel Channels

27 Examples: Radiological Surveys of Graphite Stack Irradiated graphite waste the generic problem of RBMK reactors because of volume, mass of these waste and long-lived nuclides presence. M=1760 t, ρ = 1,7 t/m 3, long-lived nuclides (predicted): Carbon-14 (5730 years), Chlorine-36 ( years???), etc. No in-situ verified data (a lack of initial RBMK data and specimens, possible variations of the impurities within each graphite stack). The calculated data - IAEA publication Progress in Radioactive Graphite Waste Management, IAEA-TECDOC-1647, 2010 (with assumptions and uncertainties) UP01 team developed of needed tools about 40 specimens (graphite bushings and samples from columns without 4 CPS channels; 2013 about 150 specimens (samples from columns without 14 Fuel channels). UP01 tool and specimens Up to 9 irradiated samples per column 27

28 Examples: Radiological Surveys of Graphite Stack Bq/g Co-60 Sum of other gamma-emitters* *Eu-154, Ba- 133, Eu-155, Сs-137, Cs-134, Nb-94, Mn-54 about 0,5 3,5 g specimens (diam. 6 mm, length mm) about 200 g per bushing (from temperature channel) 28

29 Examples: Radiological Surveys of Steels msv/h Sampling and measurements were performed through existing penetrations (РБМ-К5 assemblies. 45, 46, 47, 63) and graphite columns without channels

30 1 m 3 m Examples: Serpentinite Sampling Bq/kg top Co-60 Cs-137 Eu-152 bottom 30

31 Examples: Sampling of Sand and Concrete GLOBALLY - VLLW (CLASS A) WASTE CANDIDATE contamination of upper layer ~ 2 m of sand No or undetected contamination of other layers 31

32 THANK YOU