1. Estimation of Multiple Spurious Operation Probability KIM, SungHyun chiz@kepco-enc.com The 11 th JKPSA Workshop Japan, 19 th April 2013 April. 19th, 2013 1

2. Contents 1. Introduction 2. Case Study on MSO 2.1 Fire Induced MSO Scenarios 2.2 MSO Probability Estimation 2.3 MSO Modeling into Risk Model 2.4 Enhancement of Cable Routing 3. Conclusions 2

3. 1. Introduction 3

4. 4 What is MSO? MSO definition  Combination of single spurious operation due to fire MSO in Fire PRA  Purpose To Identify combinations of fire induced spurious operation of plant equipments which could affect safety functions and to assess the impact on the CDF/LRF  Methodology NUREG/CR-6850 : Fire PRA Methodology NEI 00-01 : Fire SSA Methodology

5. 2. Case Study on MSO 5

6. Case: Loss of SIT TK01A Path

7. 2.1 Fire Induced MSO Scenarios 7

8. Simplified Diagram for SIT TK01A Path SAFETY INJECTIO N TANK 1 TK01A M DVI NOZZLE 1A RDT 245 247 644 648 661 641 670 IRWST 608643 ATMOS

9. Internal PRA Model doesn’t model following valves because these valves are 1) normally closed and 2) require to remain closed for success. SI-V-0644-Normally Closed Position SI-V-0608-Normally Closed Position SI-V-0643-Normally Closed Position SI-V-0641-Normally Closed Position SI-V-0648-Normally Closed Position SI-V-0670-Normallyl Closed Position SI-V-0661-Normally Closed Position Internal PRA Model View

10. Postulated Fire Induced Scenarios Fire induced loss of SIT TK01A  Scenarios 1: Fire induced single spurious closure of SI-V-0644  Scenarios 2: Fire induced single spurious open of SI-V-0608 or SI-V-0643  Scenarios 3: Fire induced spurious open of two valves listed below: SI-V-0648 * SI-V-0670 SI-V-0670 * SI-V-0641 SI-V-0661 * SI-V-0648 SI-V-0661 * SI-V-0641

11. Fire PRA Model View Potential spurious operation that can impact the function of SIT TK01A  Single Spurious Operation SI-V-0644-C SI-V-0608-O SI-V-0643-O  Multiple Spurious Operation SI-V-0648-O * SI-V-0670-O SI-V-0670-O * SI-V-0641-O SI-V-0661-O * SI-V-0648-O SI-V-0661-O * SI-V-0641-O * C : Spurious Close * O : Spurious Open

12. Cable Selection for V0648/V0649

13. Simplified Diagram for Cable Selection 441-V-0648/ 441-V-0649 441-V-0648/ 441-V-0649 Termi nal Box Penetra tion Control, Power Indication Loop Controller Loop Controller Group Controller Group Controller Indication System Indication System MCR Console MCR Console Control, Power Control, Power Indication Fiber Optic CablesHardwired Cables

14. Identification of MSO Chance AUX. BLDG 120’ Reactor Containment Building Control Cabinet AUX. BLDG 137’ 6’’ Valve 661 Valve 648

15. MSO Related Circuit Analysis Tag No.Cable No.Cable FunctionFault Consequence 3-441-V-0648 3-441-C-08-L-J-A-AControl, PowerSpurious Open 3-441-C-08-L-J-B-AIndicationErroneous Indication 3-441-C-08-L-J-C-AIndicationErroneous Indication 3-441-C-08-L-J-D-AControl, PowerSpurious Open 3-441-C-08-L-J-E-AControl, PowerSpurious Open 3-441-C-08-L-J-F-AIndicationErroneous Indication 3-441-V-0661 3-441-C-08-M-J-A-MControl, PowerSpurious Open 3-441-C-08-M-J-B-MIndicationErroneous Indication 3-441-C-08-M-J-C-MIndicationErroneous Indication 3-441-C-08-M-J-D-MControl, PowerSpurious Open 3-441-C-08-M-J-E-MControl, PowerSpurious Open 3-441-C-08-M-J-F-MIndicationErroneous Indication

16. 2.2 MSO Probability Estimation 16

17. MSO Probability Estimation Raceway No Raceway Type Routing Sequence Room NoCPTGroundShielded # of Conductors # of Cables 6850 Table Probability 3-313-K-04-J16AConduit1100-C02ANNN7110-20 3-313-B-04-J01AConduit2100-C02ANNN7110-20 3-313-K-04-J17AConduit3100-C02ANNN7110-20 3-314-B-04-J01AConduit4100-C02ANNN7110-20 3-314-K-04-J07AConduit5136-C01ANNN7110-20 3-314-T-04-J10ATray6136-C01ANNN7110-20 3-314-T-04-J01ATray7136-C01ANNN71610-20.06 3-314-T-04-J05ATray8136-C01ANNN71610-20.06 3-314-T-04-J04ATray9136-C01ANNN71210-20.06 Equipment ID : 3-441-V-0648 Cable No. : 3-441-C-08-L-J-D-A

18. Probability Estimation Ref. Table Tray: M/C→M/C Inter-Cable = (0.02+0.1)/2 =0.06 Conduit: M/C→M/C Inter-Cable = (0.01+0.02)/2 =0.015 Failure Mode Probability Estimates Given Cable Damage Thermoset Cable without CPT (NUREG/CR-6850 Table 10.2) Raceway Type Description of Hot Short Best Estimate High Confidence Range Tray M/C Intra-cable0.60.20 - 1.0 1/C Inter-cable0.40.1 - 0.60 M/C → 1/C Inter-cable0.20.1 - 0.40 M/C → M/C Inter-cable0.02 - 0.1 Conduit M/C Intra-cable0.150.05 - 0.25 1/C Inter-cable0.10.025 - 0.15 M/C → 1/C Inter-cable0.050.025 - 0.1 M/C → M/C Inter-cable0.01 - 0.02

19. MSO Probability Estimation Results AUX. BLDG 120’ Reactor Containment Building Control Cabinet AUX. BLDG 137’ 6’’ Valve 661 Valve 648 0.06 0.015

20. 2.3 MSO Modeling into Risk Model 20

21. MSO Modeling into Risk Model Multiple Spurious Operation Single Spurious Operation

22. MSO Impact Evaluation MSO evaluation for individual fire compartment  Fire compartment damage state for quantification of CCDP (Conditional Core Damage Probability) given failure of cables due to fire XS-SI-V-0670-O : False (0.0) XS-SI-V-0648-O : 0.06 XS-SI-V-0661-O : 0.06 XS-SI-V-0641-O : False(0.0) XS-SI-V-0644-C : False(0.0) XS-SI-V-0608-O : False(0.0) XS-SI-V-0643-O : False(0.0)

23. 2.4 Enhancement of Cable Routing 23

24. Enhancement of Cable Routing AUX. BLDG 120’ AUX. BLDG 137’ 6’’ AUX. BLDG 100’ Control Cabinet Reactor Containment Building Control Cabinet Valve 661 Valve 648

25. 3. Conclusions 25

26. 26 Conclusions In reality, advanced plant design considers potential MSO due to fire in this case  Dedicated conduit, separation and so on In conventional plants, the potential of fire induced MSO that may impact safety functions cannot be excluded. The potential of spurious operation including MSO should be checked systematically and the results should be incorporated into Fire PRA Model.

27. Thank You!! 27