1 / 15

November 27 th -28 th , 2008, Karlsruhe

IP-EUROTRANS WP 1.5, Task 1.5.4.2c Preliminary dose calculation for the EFIT. November 27 th -28 th , 2008, Karlsruhe. Calculation Data. Accident considered: Large Leak in the Cover Gas System (DBC 4) + Fuel Subassembly Blockage (DEC).

alda
Download Presentation

November 27 th -28 th , 2008, Karlsruhe

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. IP-EUROTRANS WP 1.5, Task 1.5.4.2c Preliminary dose calculation for the EFIT November 27th-28th, 2008, Karlsruhe

  2. Calculation Data Accident considered: Large Leak in the Cover Gas System (DBC 4) + Fuel Subassembly Blockage (DEC). Fuel Damage Extension: 7 failing subassemblies (out of 180). No containment system considered. Calculation processed according to both the American and German Regulations. Source Term provided by the KTH. Fuel inventory after 1 year, and coolant temperature of 1200K (Worst Case).

  3. Fuel Source Term • Radionuclide • Mass (kg) Ngas/Ntot • 1 year • 2 years • 3 years Radionuclide 800 K 900 K 1000 K 1100 K 1200 K • Cs-135 • 5.71E+00 • 1.14E+01 • 1.70E+01 Cesium 2.02E-07 5.88E-07 1.36E-06 2.65E-06 4.55E-06 • Cs-134 • 3.70E-02 • 1.39E-01 • 2.90E-01 Strontium 1.26E-15 1.27E-14 7.96E-14 3.54E-13 1.22E-12 • Cs-137 • 5.05E+00 • 9.97E+00 • 1.48E+01 Iodine 1.45E-07 1.14E-06 5.48E-06 1.85E-05 4.85E-05 • Sr-90 • 9.79E-01 • 1.96E+00 • 2.96E+00 Noble Gases 1 1 1 1 1 • I-129 • 9.95E-01 • 1.98E+00 • 2.94E+00 • I-131 • 9.26E-02 • 9.17E-02 • 9.11E-02 • Xe-133 • 1.06E-01 • 1.06E-01 • 1.06E-01 • Xe-136 • 5.51E+00 • 1.10E+01 • 1.64E+01 • Mass composition of the fuel provided by KTH • Activity transfer from fuel to Pb coolant: • => 7 fuel rods failed (out of 180) • Activity transfer from Pb Coolant to Cover Gas System: • => Vaporized fraction of each isotope provided by KTH

  4. Activation Source Term • 753 K • 973K • 1000K • 1200K • 1.91E+04 • 4.76E+06 • 7.89E+06 • 1.62E+08 • Po-210 produced in the coolant by activation => Po-210 activity in the Cover Gas provided by KTH Po-210 activity in the Cover Gas for different T (Bq)

  5. Accident Dose Criteria • Nowadays trend: 50 mSv • German limit: 50 mSv (StrlSchV §49)

  6. Radionuclide Submersion Dose (mSv) Inhalation Dose (mSv) Cs-135 5.66E-15 4.31E-09 Cs-134 5.52E-06 3.19E-04 Cs-137 5.17E-09 2.02E-03 Sr-90 4.16E-16 6.78E-09 I-129 1.09E-12 4.69E-08 I-131 3.41E-03 5.82E-01 Xe-133 10.34 0.00 Po-210 1.21E-11 2.58E-02 TOTAL 10.35 6.10E-01 Dose results with the American methodology • Radionuclides mainly contributing to the dose for each exposure route: For fuel after 1 year and T coolant=1200K REF: NRC-RG 1.195

  7. Radionuclide Submersion Dose (mSv) Inhalation Dose (mSv) Ingestion Dose (mSv) Cs-135 1.95E-13 1.93E-09 1.09E-06 Cs-134 1.21E-05 2.73E-04 7.96E-02 Cs-137 8.87E-06 6.91E-04 3.05E-01 Sr-90 1.12E-14 5.68E-10 1.36E-07 I-129 7.11E-12 1.11E-07 9.69E-05 I-131 9.23E-04 1.93 254.60 Xe-133 7.97 0.00 0.00 Po-210 0.00 9.13E-03 8.02E-01 TOTAL 7.97 1.94 255.79 Dose results with the German methodology • The German regulation considers a third exposure route: ingestion. • Dose calculated for various ranges of ages. Mainly due to the thyroid (95%) For fuel after 1 year and T coolant=1200K. Age group: 1-2 years old REF: SSK-StrlSchV§ 49

  8. American German Mainly due to Submersion Dose (mSv) 10.35 7.97 Xe-133 Inhalation Dose (mSv) 0.61 1.94 I-131 Ingestion Dose (mSv)  - 255.79 I-131 TOTAL 10.96 265.70  - Comparison between both results

  9. Influence of the Coolant’s temperature • American methodology: dose mainly due to noble gases and almost does not change with the coolant’s temperature. • German methodology: ingestion dose mainly due to I-131 which vaporizes more at higher coolant’s temperatures.

  10. Conclusions Dose release • Dose Release exceeds the acceptance criteria for DEC: need to contain radioactive release. • Ingestion Dose is only due to I-131: filtering system required. Mass/Energy release • Not associated to DEC sequences. • Requirements for pressure relief can be considered separately from confinement requirements. • Containment pressure relief system through a filtered venting system.

  11. Subtasks definition Conditions associated to representative events analysed (DBC and DEC) • Subtask 1.5.4.1a Evaluation of analysed representative events in relation to any sequences that may imply radioactive releases and/or release of mass and energy from the reactor vessel or from other related systems, such as steam or feedwater pipe ruptures. • Subtask 1.5.4.1b Identification of potential severe accident scenarios and definition of associated conditions related to containment/confinement requirements. • Subtask 1.5.4.1c Evaluation of possible hydrogen generation and the eventual possibility of reaching explosive concentrations depending on the hydrogen mass generated and the free volume of locations in which it can accumulate. • Subtask 1.5.4.1d Based on the above results, a list of potential initiators and accident/release sequences including the associated mass and energy release estimate will be elaborated under this subtask.

  12. Subtasks definition Source Term Behaviour • Subtask 1.5.4.2a Bounding definition of potential releases to the containment and its behaviour on the basis of the different source term information available from Work Package 1.5.3 and the above analyses • Subtask 1.5.4.2b Fission products and Polonium transport mechanism will also be evaluated. • Subtask 1.5.4.2c The potential dose to the operators and the environment from the above source terms will be calculated. • Subtask 1.5.4.2d Recommendations, if required, for radioactive and fission product removal will be analysed.

  13. Subtasks definition Containment Requirements for the XT-ADS and EFIT Designs • Subtask 1.5.4.3aEvaluation of containment function performance requirements for both designs, based on the data gathered from the above activities and WP 1.2 results • Subtask 1.5.4.3b Evaluation of containment function taking into account the main features related to the following: Limitation of radionuclide releases (confinement function) Containment integrity • Subtask 1.5.4.3c Evaluation of other features such as protection against external hazards, HVAC/Filtering requirements or biological shielding • Subtask 1.5.4.3d Consideration of specific conditions that may be imposed on containment and confinement requirements

  14. Subtask Responsibilities • The Task Partners are: KTH, FZK and EA • The following split of responsibilities for the elaboration of Task 1.5.4 deliverables is proposed: • Subtask 1.5.4.1a FZK • Subtask 1.5.4.1b KTH • Subtask 1.5.4.1c KTH • Subtask 1.5.4.1d EA • Subtask 1.5.4.2a FZK/KTH • Subtask 1.5.4.2b FZK/KTH • Subtask 1.5.4.2c EA • Subtask 1.5.4.3a EA • Subtask 1.5.4.3b EA • Subtask 1.5.4.3c EA • Subtask 1.5.4.3d EA

  15. Budget • The assigned total budget allocation for Task 1.5.4 is as follows: • EA 4 m/m • FZK 4 m/m • KTH 4 m/m

More Related