November 27 th -28 th , 2008, Karlsruhe

Sheet 1

November 27th-28th, 2008, Karlsruhe

IP-EUROTRANSWP 1.5, Task 1.5.4.2c

Preliminary dose calculation for the EFIT

IP-EUROTRANSWP 1.5, Task 1.5.4.2c

Preliminary dose calculation for the EFIT

Sheet 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).

Sheet 3

Fuel Source Term 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

1.64E+011.10E+015.51E+00Xe-136

1.06E-011.06E-011.06E-01Xe-133

9.11E-029.17E-029.26E-02I-131

2.94E+001.98E+009.95E-01I-129

2.96E+001.96E+009.79E-01Sr-90

1.48E+019.97E+005.05E+00Cs-137

2.90E-011.39E-013.70E-02Cs-134

1.70E+011.14E+015.71E+00Cs-135

3 years2 years1 year

Mass (kg)Radionuclide

11111Noble Gases

4.85E-051.85E-055.48E-061.14E-061.45E-07Iodine

1.22E-123.54E-137.96E-141.27E-141.26E-15Strontium

4.55E-062.65E-061.36E-065.88E-072.02E-07Cesium

1200 K1100 K1000 K900 K800 KRadionuclide

Ngas/Ntot

Sheet 4

Po-210 produced in the coolant by activation

=> Po-210 activity in the Cover Gas provided by KTH

Activation Source Term

1.62E+087.89E+064.76E+061.91E+04

1200K1000K973K753 K

Po-210 activity in the Cover Gas for different T (Bq)

Sheet 5

Accident Dose Criteria

Nowadays trend: 50 mSv

German limit: 50 mSv (StrlSchV § 49)

Sheet 6

Radionuclides mainly contributing to the dose for each exposure route:

For fuel after 1 year and T coolant=1200K

Dose results with the American methodology

REF: NRC-RG 1.195

6.10E-0110.35TOTAL

2.58E-021.21E-11Po-210

0.0010.34Xe-133

5.82E-013.41E-03I-131

4.69E-081.09E-12I-129

6.78E-094.16E-16Sr-90

2.02E-035.17E-09Cs-137

3.19E-045.52E-06Cs-134

4.31E-095.66E-15Cs-135

Inhalation Dose (mSv)

Submersion Dose (mSv)

Radionuclide

Sheet 7

Dose results with the German methodology

REF: SSK-StrlSchV § 49

The German regulation considers a third exposure route: ingestion.

255.791.947.97TOTAL

8.02E-019.13E-030.00Po-210

0.000.007.97Xe-133

254.601.939.23E-04I-131

9.69E-051.11E-077.11E-12I-129

1.36E-075.68E-101.12E-14Sr-90

3.05E-016.91E-048.87E-06Cs-137

7.96E-022.73E-041.21E-05Cs-134

1.09E-061.93E-091.95E-13Cs-135

Ingestion Dose (mSv)

Inhalation Dose (mSv)

Submersion Dose (mSv)

Radionuclide

For fuel after 1 year and T coolant=1200K. Age group: 1-2 years old

Mainly due to the thyroid (95%)

Dose calculated for various ranges of ages.

Sheet 8

Comparison between both results

 -265.7010.96TOTAL

I-131255.79 -Ingestion Dose (mSv)

I-1311.940.61Inhalation Dose (mSv)

Xe-1337.9710.35Submersion Dose (mSv)

Mainly due toGermanAmerican

Sheet 9

Influence of the Coolant’s temperature

TemperatureDose with American methodology (mSv)

Dose with German methodology (mSv)

800 K 10.35 10.67

900 K 10.36 15.89

1000 K 10.41 38.64

1100 K 10.58 107.19

1200 K 10.96 264.52

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.

Sheet 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.

Sheet 11

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.

Subtasks definitionConditions associated to representative events analysed (DBC and DEC)

Sheet 12

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.

Subtasks definitionSource Term Behaviour

Sheet 13

Subtask 1.5.4.3a Evaluation 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

Subtasks definitionContainment Requirements for the XT-ADS and EFIT Designs

Sheet 14

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

Subtask Responsibilities

Sheet 15

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

Budget