task 1.5.4 containment assessment

Sheet 1November 13th-14th, 2007, Madrid

Task 1.5.4 Containment Assessment

IP-EUROTRANSDOMAIN 1 Design WP 1.5

Safety Assessment of the Transmutation System Design

IP-EUROTRANSDOMAIN 1 Design WP 1.5

Safety Assessment of the Transmutation System Design


• Fission product confinement and control

• Protection against external events

• Biological shielding

Containment System Safety Functions


• Limitation of radionuclide releases

• Fission and spallation product removal mechanisms

• Containment isolation

• Leak tightness

• Containment integrity

• Structural behaviour

• Energy management system

Fission product confinement and control


• Representative events selection DBC/DEC

– Definition of mass/energy releases

– Source term definition

• Definition of fuel damage extension

• Dose calculation. Different hypothesis

• Comparison with acceptance criteria

• Containment integrity requirements

Containment Requirements


• DBC

– Primary HX tube ruptures

– Secondary coolant pipe breaks

– Cover gas system pipe break

• DEC

– Fuel sub-assembly blockage

Representative events


DBC conditions

DBCFUEL DAMAGE

SOURCE TERM MASS/ENERGY RELEASE

DBC1 No fuel damage Normal operation N/A

DBC2 No fuel damage Normal operation Limited (Small leakages)

DBC3No fuel damage except test pins

Normal operation + test pins Large leakages/HX tube ruptures

DBC4Localised damage

Extension of damage to be defined ¿10%? Total SCS dumping


DEC conditions

DECFUEL DAMAGE

SOURCE TERM MASS/ENERGY RELEASE

Complex sequences

Localised damage

Extension of damage to be defined ¿10%?

No DEC associated to significant mass and energy releases to the containment

Severe accidents

Core damage/coolable inside vessel Core damage

No DEC associated to significant mass and energy releases to the containment


Relevant conclussions

oHigh mass/energy release events not associated to DEC sequences

oThis allows to considering requirements for pressure relief separately from confinement requirements

oContainment pressure relief system through a filtered venting system

oDose calculations to show compliance with acceptance criteria


• 10 % FUEL RODS FAILED (0.1 % during Normal Operation)

• EXCLUSION AREA BOUNDARY (EAB): 1000 m

• SOURCE TERM extrapolated from Superphenix MOX fuel

• LEAK RATE from containment: 1 % volume/day

• Acceptance criterion: DBC4 50 mSv (consequences have to be

assessed for a long period – 50 years)

Dose assessment


Some credits that may be considered:

1. Po WALL DEPOSITION

2. Po TRAPPING (FILTERING SYSTEM)

3. Po NON-VOLATILITY (% Po non-evaporated)

4. I RELEASE-TO-CONTAINMENT FRACTION

5. Cs DEPOSITION, FILTERING OR ANY OTHER WAY OF REMOVAL

Credits


CreditCase

0 1 1b 2 2b 3

Po trapping (%) 0 0 0 0 0 0

Po wall deposition (%) 0 0 0 0 0 0

Po non-volatility (%) 0 25 25 90 90 90

I fraction release 1 1 0,5 1 0,5 0,5

Cs deposition (%) 0 0 0 0 0 25


Inhalation Dose

Dim(t)=A'(t)·FDC·/Q(t)

Calculation equations

Immersion Dose

Dih(t)=A'(t)·FDT·/Q(t)·BR

D(t): Dose after a given time t, [Sv]A’(t): Activity released from containment at a given time t, [Bq]FDC/FDT: Dose conversion factor for each radionuclide/Q(t): Offsite atmospheric dispersion factor, [s/m3]BR: Breathing rate, [m3/s]


Results

Isotope

Dose after 1yr (mSv)

Case 0

Case 1

Case 1b

Case 2

Case 2b

Case 3

Po-210

35,84 3,62 3,62 1,98 1,98 1,98

I 6,50 6,50 1,09 6,50 1,09 1,09

Others*

16,24 16,24 16,24 16,24 16,24 3,11

TOTAL

58,58 26,36 20,95 24,72 19,31 6,18* Mostly due to Cs


1

10

100

0 20 40 60 80 100 120 140

t (d)

Dos

e (m

Sv)

Cat. 4 Safety Principles (50 mSv)Case 0Case 1Case 1bCase 2Case 2bCase 3

Dose time-evolution for assessed cases


Dose gets Safety Principles Limit for category 4 events (50 mSv) after 20 days in case 0

This limit has not been reached for any other cases during the 1st year

Preliminary conclusions


• Update source term (which has been extrapolated from

Superphenix reactor) in order to obtain more realistic results

• Further considerations about Po and Hg should be taken

into account regarding chemical toxicity that have not been

considered in these radiological dose calculations

Objectives


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.


Subtasks definition

Containment Requirements for the XT-ADS and EFIT Designs

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


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


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


CONTENTS

1. INTRODUCTION AND PURPOSE

2. INTERNATIONAL GENERAL DESIGN CRITERIA FOR CONTAINMENT

3. GENERAL SAFETY CRITERIA. CONTAINMENT CRITERIA

3.1 DEFENCE-IN-DEPTH

3.2 SAFETY FUNCTIONS

3.3 LINES OF DEFENCE (LOD) METHODOLOGY

4. GENERAL FUNCTIONS OF THE CONTAINMENT

4.1 CONFINEMENT AND CONTROL OF RADIOACTIVE PRODUCTS

4.2 PROTECTION AGAINST EXTERNAL EVENTS

4.3 CONTAINMENT ACCESIBILITY

5. BARRIERS AGAINST THE RELEASE OF RADIOACTIVE PRODUCTS

5.1 BARRIERS AGAINST THE RELEASE OF RADIOACTIVE PRODUCTS FROM THE FUEL

5.2 BARRIERS AGAINST THE EMISSION OF RADIOACTIVE PRODUCTS FROM THE TARGET

6. DESIGN BASIS CONDITIONS. CONTAINMENT DESIGN REQUIREMENTS

6.1 DESIGN BASIS CONDITIONS. LBE-COOLED XADS DESIGN

6.2 DESIGN BASIS CONDITIONS. GAS-COOLED XADS DESIGN

7. DESIGN EXTENSION CONDITIONS. REQUIREMENTS FOR THE DESIGN OF THE CONTAINMENT

7.1 CONTAINMENT HEAT REMOVAL SYSTEMS

7.2 LBE-COOLED XADS DESIGN

7.3 GAS-COOLED XADS DESIGN

8. SUMMARY OF CONTAINMENT DESIGN REQUIREMENTS

8.1 CONTAINMENT GENERAL ARRANGEMENT

8.2 CONTAINMENT HEAT REMOVAL

8.3 CONTAINMENT LEAKTIGHTNESS

8.4 STRUCTURAL DESIGN

8.5 CONTAINMENT ISOLATION

8.6 RADIATION PROTECTION

9. PENDING ITEMS

10. REFERENCES

APPENDIX A TABLES

APPENDIX B GENERAL DESIGN CRITERIA FOR CONTAINMENT IN AMERICAN, GERMAN, IAEA AND EUR STANDARDS

B.1 CURRENT GERMAN CONTAINMENT FUNCTION-RELATED REGULATIONS

B.2 CURRENT USA CONTAINMENT FUNCTION-RELATED REGULATIONS

B.3 CURRENT EUROPEAN UNION REGULATORY CRITERIA

B.4 CURRENT INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA) CRITERIA

B.5 EUR CRITERIA RELATED TO CONTAINMENT FUNCTION

B.6 KEY CRITERIA

task 1.5.4 containment assessment

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