WASTE ACCEPTANCE REQUIREMENTS FOR THE KONRAD REPOSITORY

Transcription

1 WASTE ACCEPTANCE REQUIREMENTS FOR THE KONRAD REPOSITORY Peter W. Brennecke Bundesamt für Strahlenschutz (BfS) Salzgitter, Germany IAEA - DISPONET Workshop " Waste Acceptance Criteria For Disposal of Very Low, Low, and Intermediate Level Waste " Peine / Salzgitter, Germany, September 28-30,

2 Contents Introduction The KONRAD Repository Site-Specific Safety Assessments KONRAD Waste Acceptance Requirements KONRAD Requirements as of December 1995 Additional Requirements Imposed by the Licensing Authority Conclusions and further Steps 2

3 Radioactive Waste Disposal in Germany Basic principle of radioactive waste disposal in the Federal Republic of Germany: Disposal of all types of solid or solidified radioactive waste (short-lived, long-lived) in deep geological formations. Exclusion of liquid and gaseous radioactive waste from disposal. 3

4 The Konrad Repository - History Abandoned iron ore mine - Location near Salzgitter, Federal State of Lower Saxony, Northern Germany - Host rock Coral Oolite - Emplacement depth 800 m to 1,300 m - Type of waste Radioactive waste with negligible heat generation (i.e., LLW and ILW) - Volume of waste packages Planned: up to 650,000 m³ Licensed: 303,000 m³ at max. - Total alpha emitter activity Bq - Total beta/gamma emitter activity Bq - Licensing procedure August 31, 1982 to May 22,

5 Geological Cross Section of the Konrad Site iron ore deposit (Upper Jurassic, Malm) 12 to 18 m thick thick mudstone layers (Lower Cretaceous) 200 to 400 m thick 5

6 Perspective of Shaft Area Konrad 1 6

7 Perspective of Shaft Area Konrad 2 7

8 Konrad Disposal and Ventilation Scheme shaft Konrad 1 emplacement area (controlled area) sewage shaft Konrad 2 Main features separation in space of waste package and debris transports parallel ventilation of deposition and drifting areas old mining areas, not for disposal excavation for radioactive waste disposal of radioactive waste fresh air return air (conventional) return air (contaminated) debris transport path transport path for radioactive waste 8

9 Safety Criteria for the Disposal of Radioactive Waste in a Mine (January 1983) The required safety of a repository constructed in a geological formation must be demonstrated by a sitespecific safety assessment which includes the respective geological situation, the technical concept of the repository including its scheduled mode of operation, and the waste packages intended to be disposed of. In the post - closure phase, the radionuclides which might reach the biosphere via the water path as a result of transport processes not completely excludable must not lead to individual dose rates which exceed the limiting values specified in section 47 of the Radiation Protection Ordinance (0.3 msv/a concept). 9

10 Konrad Site - Specific Safety Assessment Normal operation Assumed incidents Thermal impact upon the host rock Criticality safety Long - term radiological effects Pollution of the near - surface groundwater 10

11 Annual Individual Dose Rate Limits (for normal operation) Occupationally exposed persons (category A) 55 Radiation Protection Ordinance 20 msv/a effective dose in addition further organ doses are to be considered Euratom Basic Safety Standards 20 msv/a 5 msv/a BfS dose levels for planning (Konrad Repository) 0.5 msv/a mean value from direct radiation effective dose due to inhalation Population / environment 46 Population / environment msv/a by direct radiation 1.0 msv/a (effective dose) 0.3 msv/a 1.8 msv/a 0.9 msv/a by release via air and water path: effective dose, gonads, uterus, red bone marrow bone surface, skin other organs and tissues by direct radiation and release via air and water path 20 % of the limits of the former RPO 20 % of the limits of the former RPO 11

12 Annual Individual Dose Rates (in case of incident) Occupationally exposed persons (category A) Population / environment 49 Radiation Protection Ordinance 50 msv 300 msv 500 msv 150 msv BfS dose levels for planning Limits of the RPO as for environment effective dose, gonads, uterus, red bone marrow bone surface, skin extremities (incl. skin) thyroid, other organs and tissues Limits of the RPO deduction of release rate limits waste acceptance requirements 12

13 Relevant Radiation Exposures Calculated for Periods of Time up to 10 6 a Dose 47 StrlSchV (RPO) 0,3 msv/a 13

14 Additional Evidence Supporting the Long-Term Safety Assessment Age of the Konrad groundwater at least 10 7 years, and possibly as long as years, corresponding to the age of the geological formation. Indication of groundwater movements in the range of less than 1 cm per 10 3 years (stagnant groundwater). Increase of the Konrad groundwater salinity with depth. Indication of a diffusion-dominated vertical transport of substances. Consideration of transport of substances with groundwater flow as conservative assumption (300,000 years); bandwidth of groundwater flow times due to model calculations: 330,000 years up to 38.8 million years. 14

15 Konrad Waste Acceptance Requirements Konrad Waste Acceptance Requirements as of December 1995 were prepared and examined within the Konrad repository licensing procedure, form part of the Konrad license issued on May 22, 2002, define the safety - related envelope or framework for all types of short - lived and long - lived radioactive waste with negligible heat generation (i.e., LLW and ILW) intended for disposal in the Konrad repository, provide guidance to radioactive waste conditioning and are successfully applied by the waste generators and conditioners, and are presently revised. 15

16 Survey on the Structure of the Konrad Waste Acceptance Requirements (1) 1. Introduction 2. General basic requirements on radioactive waste to be disposed of 3. General requirements on waste packages - Local dose rate - Surface contamination - Depressurized delivery 4. Requirements on waste forms - Basic requirements - Waste form groups - Exhausting of activity limiting values - Filling of waste packages 5. Requirements on waste containers/packagings - Basic requirements - Waste container classes - Incident resistant packagings - Inner containers 16

17 Survey on the Structure of the Konrad Waste Acceptance Requirements (2) 6. Activity limitations - Permissible activities for individual radionuclides per waste package - Total activities - Declaration of radionuclides 7. Mass limitations of non-radioactive harmful substances - Permissible masses - Threshold values - Waste assignments 8. Delivery of waste packages - Compliance with transport regulations - Permits - Marking of waste packages - Requirements on shipping units 17

18 Cylindrical Cast Iron Container Type II D = 1,060 mm H = 1,500 mm V = 1.3 m³ 18

19 Sheet Steel Container Type I L = 1,600 mm W = 1,700 mm H = 1,450 mm V = 3.9 m³ 19

20 Concrete Container Type IV L = 3,000 mm W = 1,700 mm H = 1,450 mm V = 7.4 m³ 20

21 Maximum Activities Of Relevant Radionuclides And Radionuclide Groups Radionuclide / Radionuclide Groups Activity in Bq 21 H 3 6,0 E 17 C 14 4,0 E 14 I 129 7,0 E 11 Ra 226 4,0 E 12 Th 232 5,0 E 11 U 235 2,0 E 11 U 236 1,0 E 12 U 238 1,9 E 12 Pu 239 2,0 E 15 Pu 241 2,0 E 17 Total Alpha-Emitters 1,5 E 17 Total Beta-/Gamma-Emitters 5,0 E 18

22 Additional Requirements: Nuclear Law Fifteen additional waste - related requirements imposed by the licensing authority: Four requirements with respect to criticality safety which address permissible activities / activity distributions of fissile material in the waste form. Eight requirements with respect to quality assurance / quality control which address, inter alia, criticality safety aspects and procedures concerning radioactive waste to be repatriated from conditioning in foreign countries. Three more general requirements. Revision of the Konrad waste acceptance requirements and related quality assurance / quality control measures. 22

23 Additional Requirements: Water Law Konrad license, Appendix 4: Water Law Permit. Allowable masses of 94 groundwater - relevant elements and organic compounds (non - radioactive waste package constituents). Two additional requirements imposed by the licensing authority: Control of the chemical composition of the waste packages to be disposed of in the Konrad repository, registration and balancing the masses of the harmful non - radioactive substances, estimation of such masses in legacy waste. Annual reporting to the competent authority dealing with water law. 23