Design solutions for the creation of VLLW disposal facilities in the Russian Federation North-West region

Transcription

1 OPEN JOINT STOCK COMPANY «EAST-EUROPEAN LEADING SCIENTIFIC RESEARCH AND DESIGN INSTITUTE FOR ENERGY TECHNOLOGIES» (OJSC «Leading institute «VNIPIET») Design solutions for the creation of VLLW disposal facilities in the Russian Federation North-West region Demin A.V., Velikina S.А. IAEA CEG Workshop February 24-26, 2009 Bommersvik, Sweden

2 Urgency of the problem The urgency to create the VLLW DF is caused by the following: The RF North-West region hosts a lot of enterprises of nuclear and radiation hazard. Of special importance are the former coastal technical bases at the Andreeva Bay and Gremikha village. SNF and RW storage in unsuitable structures and even at open pads. Geology of the radioactive materials storage area presented by loose rock with a high permeability (and as a result-radiation contamination of the area). At the present time a decommissioning concept for the Andreeva Bay and Gremikha village has been adopted and a complex of rehabilitation activities is under way. Up to now conservative and costly solutions were used in the creation of the RW management systems which were based on the valid RW classification system. Currently a new group of very low level waste (VLLW) is being singled out within the RW classification system. The VLLW does not satisfy the exemption criteria but at the same time it does not require a high level of isolation and radiation shielding which allows to dispose of it in the near-surface facilities. The VLLW has a comparatively short period of potential hazard (on the average up to 100 years) which allows to place the VLLW disposal facilities on the site to be rehabilitated. Creation of the VLLW disposal facilities is a key to resolve optimization problems of RW long-term storage and treatment since singling out the VLLW category from the total radwaste steam will reduce VLLW volumes coming to the long-term RW storages. The paper presents main provisions of the first project of the VLLW disposal facility within the RW North-West region on the Andreeva Bay TSF site. 2

3 Regulatory baseline and VLLW characteristics Up to now the VLLW category was unavailable in the RF classification system and, consequently, no VLLW management and disposal baseline was available. The OSPORB-99 was the only document in which this waste group was inexplicitly mentioned. Category Materials containing radioactive materials β- Specific activity *, кbq/kg α- (TUE excl) TUE Management requirements No restriction in use 0,3 (individual annual effective dose no higher than 10 µsv/year); Collective annual effective dose no higher than 1 man-sv) Outside the scope of RS regulation and are not subject to RM (item 1.4; 7.1 of NRB-99). No restrictions for use in economic activity (OSPORB-99 item ) Restricted use from 0,3 to 10 2 from 0,3 to 10 1 from 0,3 to 1 To be monitored. Management restrictions, OSPORB-99 items , Radioactive waste LLW from 10 2 to10 3 from 10 1 to 10 2 from 1 to 10 1 Within scope of Federal legislation and other RW ILW from 10 3 to 10 7 from 10 2 to 10 6 from 10 1 to 10 5 HLW over 10 7 over 10 6 over 10 5 * - if radionuclide composition is unknown management FR 3

4 Regulation baseline and VLLW characteristics In March 2008 regulatory document R Hygienic requirements for industrial waste management at the federal State unitary enterprise North Federal radwaste management enterprise was brought into force. The Regulation has been developed specially for the FGUP SevRAO enterprises and sets requirements to assure safe management of industrial waste having low levels of toxic materials and man-made radionuclides historically stockpiled and arising in the rehabilitation of SNF and RW temporary storage at the SevRAO enterprises and also sets requirements for the design, maintenance and operation of the disposal landfill. 4

5 Regulation baseline and VLLW characteristics A unique feature of the SevRAO radwaste is caused by the fact that the main contribution (up to 95%) to its activity and to forming the staff exposure dose is made by 60 Co, 90 Sr, 137 Cs. The rise in specific activity in the package up to 30.0 kbq/kg is allowed in the radiation safety analysis for the disposal system in view of the site characteristics, design feature, landfill barrier specifications and radionuclide composition of the waste. Waste whose specific activity reaches kbq/kg may be disposed of in individual packages (no more than 10% of the total disposal volume). VLLW permissible characteristics to be sent to the SevRAO disposal landfill, with isotopic composition of 90 Sr (20%) and 137 Cs (80%). VLLW А sp in the package, (kbq/kg) Мах А sp in the package, (kbq/kg) surface β- contamination (part/м*sm 2 ) Exposure rate, (µsv/hr) α - content (%) 0,3-30,0 100,0 50,0-500,0 < 1,0 0,1 m off < 0,1 5

6 General approach to decision-making on VLLW DF construction Concept development of site rehabilitation Low ground waters level Trenches Identification of VLLW generation phases Projected evaluation of VLLW generation in every phase Capacity identification of disposal facility for each phase Development of site selection criteria for VLLW disposal facility Preliminary waste acceptance criteria High ground waters level Development disposal facility design depending on site selection Preliminary safety assessment Surface facility Selection of disposal method (surface, shallow, near-surface), waste disposal depth, barrier properties and quantity, barrier purpose to be determined in landfill design depending on: waste form; waste quantity; radionuclide composotion; total and specific activities; hazard category; host rock properties; geological and hydrological characteristics of disposal facility site (ground water, in particular). Indentification of final acceptance criteria and update of disposal facility design 6

7 Preliminary VLLW disposal criteria Approach to consider waste data storage International experience Regulatory requirements Disposal facility concept Preliminary waste acceptance criteria Preliminary safety assessment Final Final requirements for for waste parameters Potential risk: Available waste, probably, does not or partway meet requirements. 7

8 VLLW generation sources at Andreeva Bay TSF The following are VLLW generation sources during TSF rehabilitation: buildings and structures to be dismantled in construction of the SNF and RW management shops, solid RW stockpiled in old RW storage facilities and at open pads, facility area when performing rehabilitation works. The following kinds of VLLW will be mainly generated when performing these works: building constructions (concrete, bricks, rebars, etc.), soil, individual protection means for the staff, package materials. The VLLW are collected near the places of its generation. 8

9 DF construction phases and projected VLLW volumes at the Andreev Bay VLLW PHASE-1 Waste arising in preparation for construction (~ м 3 ) PHASE-2 Waste arising in operation of SNF and RW management complexes (~ м 3 ) PHASE-3 Waste arising in facility decommissioning and site rehabilitation (~ м 3 ) 9

10 Disposal facility site selection area close to the wharf former boiling-house area former fuel oil tanks area area close to the former SNF storage area near the substation 10

11 VLLW disposal facility options Option 1А. Construction of the new nearsurface facility (surface facility) Option 1B. Construction of the new near surface facility (shallow facility) Option 2. Use of the available structures for disposal facility arrangement (based on DSH, bldg.6, bldg. 7-7В, bldg.67). Bldg. 6 as an example 1 very low level waste 2 buffer material 3 engineered barrier system of the underlying shield 4 drainage system 5 engineered barrier system of the covering shield 11

12 VLLW preparation for disposal. Packages types The VLLW are classified and collected into packages of different types depending on: value of specific activity and chemical characteristics; fire and explosion hazard; size (pine and large-sized); adopted waste treatment procedures; methods of use in economic purposes or of disposal. The VLLW are prepared by the analogy with solutions used in Sweden. Soft waste in briquetted to the volume of 1 m 3 at the 70 t compaction facility The VLLW loaded into containers. In use are: 1,5 м 3 containers both metal and soft of the Big-Bag type, Specially prepared large-sized containers. 12

13 VLLW disposal facility specifications at Andreev Bay Modified option in view of terrain feature 13

14 Economic indicators comparison of different DF disigns Indicators Andreev Bay 2000 м 3 Oskarhamn м 3 Unit (thous. Unit (thous. Σ (thous. rouble) rouble / m 3 ) Σ (thous. rouble) rouble / m 3 1. Sorption bed, raft 6609, ,5 2,4 2. Disposal facility loading equipment 3284,1 1,6 3. Off-wall drain, chute, well 320,6 0,2 4. Campaign ,6 (1000 м 3 ) 3,2 5899,2 (1600 м 3 ) 3,7 - top stone layer 1062,5 - top sand layer 294,1 - high-density polyethylene layer 73,6 - bentonite cover 279,1 - smoothing sand layer 612,8 - concrete block placement 850,5 5. Further campaigns 3172,6 (c-n м 3 ) 3, ,1 (c-ns м 3 ) 2,4 Total for items ,0 8, ,8 4,9 6. Retaining wall 2467,9-7. Hanger with briquetting press 7856,4-8. Container cutting 2578,2-9. Motor roads 1992,9-10. Observation wells 1141,0 - Total for items ,4 16, ,8 4,9 11. Detail design 1973,7 1,0 7374,0 0,7 Total for items ,1 17,3 (470 /м 3 ) 56779,8 5,7 (154 /м 3 ) 14

15 Analysis of economic efficiency in creating the VLLW DF 30-60% RW generated in decommissioning the facilities of atomic energy utilization may be classified as very low-level waste. Average cost of low level solid RW management Country, Facility Construction cost of 1 m 3 solid RW storage facility Total cost (conditioning, long-term storage/disposal of 1 m 3 ) Germany ~ ~ Sweden $ ~ $ United Kingdom ~ ~ USA 3700 $ $ Russia LSK Radon MosNPO Radon ~ rouble руб. (storage) rouble Average data ~ Simple estimate shows that saving of 2,7 M per each 1000 м 3 of VLLW can be obtained when singling out the new group of VLLW (with on average disposal cost of ~300 /m 3 ) from the LLW group and creating an individual disposal flowsheet. VLLW disposal immediately on the site will allow to save more than a half of funds to be spent for RW management. 15

16 Conclusion A substantial part of RW (30-60%) generated in decommissioning the AEU buildings and structures may be classified as very low-level waste; The VLLW category singled out from the total stream of radwaste and the VLLW disposal facilities will allow to reduce waste volume coming to the long term RW storage facilities and to save more than a half of funds to be spent for RW management

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