ML19209C271

Responds to NRC 790917 Ltr Re Interaction Between nonsafety- Grade & safety-grade Equipment.Util Assessment Performed.No Impacts on Required Safety Actions Identified.One Potential Analysis Conclusion Identified & Justified

ML19209C271
Person / Time
Site:	Pilgrim, 05000471
Issue date:	10/05/1979
From:	Rosen S BOSTON EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NED-79-73, NUDOCS 7910120314
Download: ML19209C271 (10)

Text

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SOETON EOlsON COMPANY acNamA6 arrices aco savtaroN star:7 SO ETON. M A5 5 ACNU SETTE O 219 9 STE5 HEN b ROSEN MANAGEE NUCLEAR ENGINEEA8NS DEPARTMENT NED 79- 73 October 5,1979 Harold R. Denton, D! rector Office of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, DC 20555

SUBJECT:

Resoonse to Letter Entitled, " Potential Unreviewed Safety Question on Interaction Between Non-Safety Grade Systems and Safety Grade Systems", Harold R. Denton to All Operatinn Linht Water Reactors, Sectember 17, 1979

Dear Mr. Denton:

Please find enclosed per the request of the subject letter an assessment of Pilgrim Nuclear Power Station I concerning the potential ef fects of non-safety system failures (caused by a high energy pipe break) on safety system performance. More specific and' ccmprehensive information and analysis requested by the NRC Staff (Thursday briefing, September 20, 1979) is a;so contained.

The assessment has identified no impacts on required safety actions and one potential analysis conclusion which would increase the consequences of a high energy pipe break. The consequences of analyzed high energy pipe breaks considered are:

1. Calculated Peak Clad Temperature

2. Peak Containment Pressure

3. Peak Suppression Pool Temperature 4 Radiological Releases in particular, the assessment concludes that Pilgrim Statien air operated reactor head vent valves (2" line) utilize solenoid valves of the generic type outlined in NRC Sulletin 79-01A and a high energy pipe break environment could cause the two series head vent valves to open during the initial phases of the event. An analysis shows that such a bounded worst case may have a + 10 0F impact on Peak Clad Temperature. The analysis conservatively assumes that both head vent valves open completely and instantaneously coincident witn the worst pipe break inside containment, i

l l 2:1')c ' ;l I. (

7910120 ]

BOSTON EDISQN COMPANY H. R. Denton Page 2 NED 79-73 Boston Edison justifies continued operation of Pilgrim Nuclear Power Station I based on:

1. The comprehensive review of the environmental interactions (due to analyzed high energy pipe breaks) between non-safety systems and safety systems; and

2. The comDined low probability and relative insignificant ef fect of a " Pipe Break inside Containrent" result!ng in inadvertent operation of the reactor head vent valves, it is Bostor, ddison's Intent to eliminate the potential interaction of a " Pipe Break inside Containrent" and reactor head vent valve maloperation during the next scheduled or unscheduled plant outage.

Very truly yours, s_ )

.)

Enclosures:

1. Legend and abbreviations used in the "Environrental Interaction Table",

Parts I and 11.

2. Environmenta l Interaction Table, Part !

3. Environmental Interaction Tabio, Part !!

1 1 1n 177 i l9d J-

Commonwealth of Massachusetts)

County of Suifolk )

Then personally appeared before me Stephen L. Rosen, who being duly sworn, did state that he is the Nuclear Engineering Manager of Boston Edison Company, that he is duly authori::ed to execute the foregoing statement in the name and on be-haif of Bostor. Edisen Company and tpat the statements are true to the be st of his knowledge and belief. j h '[ A

/s/ Dorothy M. Looes Notary Public My Commission E-mires: July 6, 1984 4 4 ? ' 's M *1 l . ,

a

PILGRIM NUCLEAR POWER STATION 1 ENVIRONMENTAL INTERACTION TABLE PARTS I & II Legend

1. Environmental Induced malfunction may provide adverse response, i.e.

oIncreased Drywell pressure eIncreased wetwell pressure eIncreased suppression pool tenperature eIncreased Fuel Clad Temperature

2. Environmental induced malfunction will not provide advarse response.

3. System is qualified for adverse environment.

4. System will not experience adverse environment.

Abbreviations M.G. -Motor Generator MCC -Motor Control Center SYS -System INST -Instrumentation TRANS -Transmi tter MONIT -Moni toring RPS -Reactor Protection System RBCCW -Reactor Building Closed Cooling Water Systen RWCU -Reactor Water Clean Up System ISOL -Isolation RPV -Reactor Pressure Yessel LIQ -Liquid CRD -Control Rod Drive RHR -Residual Heat Removal System DW -Drywell RB -Reactor Building TB -Turbine Building CB -Control Building CR -Control Room N/A -Not Applicable OPER -Valve Operator FDWTR -Feedwater k 33-4 17 4 i 1[

)

PILGRIM NUCLEAR POWER STATION ENVIRONMENTAL INTERACTION TABLE PART I Non-safety systems whose environmentally induced malfunccion cannot affect plant sTfety response during a high energy pipe break.

1. Air Ejector Offgas Radiation Monitoring System

2. Main Stack Radiation Monitoring System

3. Building Exhaust Vent Radiation Monitoring System

4. Radwaste Liquid Discharge Radiation Monitoring System

5. xBCCW Liquid Radiation Monitoring System

6. 'ndensate Storage Inlet Radiation Monitoring System

7. Standby Gas Treatment Exhaust Radiation Monitoring System

8. Control Room Ventilation Intake Radiation Monitoring System

9. Area Radiation Monitoring System

10. Environs Radiation Monitoring System

11. Fuel Pool Cooling and Cleanup 5ystem

12. Service Air System

13. Portable and Sanitary Water system

14. Process Sanp'. ing System

15. Communications System

16. Station Lighting

17. Main Condenser Gas Removal and Turbine See',ing System

18. Process Computer (Parts - Rod Worth Minimizer Program when <10% Rx.

Power is Safety Related)

19. Instrument Air System (Parts - Safety Related Accumulators,, Valves and Piping not included) 20,. Standby Liquid Control Sys (Parts)

21. Fuel Handling Eqaipmer.t

22. Screen Wash and H',po-Chlorination System

23. Maintenance Monorails and Hoists ,- ,

,l44 i

, _$ y.

2.

24. Generator

25. Generator Cooling

26. Generator Excitation

27. Turbine Building Closed Cooling Water system

28. Security System

29. 120 VAC POWER SYSTDI

] 14ei. u'? l 7, aK f

Pg. 1 of-4 PflGRIM NUCLIAR l'0WER SIAT!DN 1 N i NVI RoretINT At INIF RAli!ON TAl:1 f m PART II c DJ

~

Main Ste.vi reeikater LDCA 1~

Insi4T7e sTde Reactor Tu~rfine Reactor RWCU RCIC HRI -

Systems __ _ Location Small Turbine Re c t'ar Reactor Reactor

_ L a rge _Rullding Bul g 3_ Inside Building _ Bui ldirl Small Lar3e, F M ng Buildin3_,,Buildin t Neutron flonitoring_Sys eSource Range DW/RB/CR 2 2 2 4 2 2 4 2 2 2 _4 4 olocal Power Range DW/RB/CR 2 2 2 4 2 2 4 2 eRod Block Monitor 2 ]_ 4 4 DW/RB/CR 2 2 2 4 2 2 4 2 2 '

eTransverse In-core f 4 4 Probe DW/RB/CR 2 2 2 4 2 2 4 2 2 2 4 4

_'tBCCW (Pat 65) RB 4 4 2 4 4 2 4 4 4 I 2 4 4 Fire Protection RB/TB 4 4 2 2 4 2 2 4 4 2  ? 2 HVAC All 2 2 2 2 2 2 2 2 2 2 2 Makeuo Water Treatment TB 4 4 Equipment and Floor p ain System 2 2 4 2 2 4 4 2 li_ 2

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RB/TB/DW 2 2 4 4 2 4 4  ?  ?

F.a W Cond. Gas Removal _ d 4 A

& Turb. Seallnq Sys. TB 4 4  ? 2 4 7, 2 Circ. Wtr. __t_ c , 7 2 2 Circulating Water Sys. House 4 4 4 4 4 4 4 4 4 4 To5densate Demineralizer ,

4 4 System TB 4 4 2 2 4 2 2 4 4 2 2 2

_ Condensate System TB 4 4 4 2 4 4 2 4 4 4 Condensate Transfer & 4 4 Storage System TB 4 4 4 2 4 4 2 4 4 4 4 4 Unit AC Power Source TB 4 4 2 2 4 2 2 4 4 i

2 2 2

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Systems Small Large Turbine Reactor Reactor Reactor

_ Location Building Building Inside Building Building Small _ _ _

Lag Building Building Building 24V DC Power Sys. RB 4 4 2 2

_4 2 2 4 4 2 2 - 2 Cont. Atmos. Monitoring DW/RB 2 2 2 4 2 2 4 2 2 2 2 2 Reactor Vessel Hd Vent DW 2 2 Main Turb. & Controls TB 4 4 2 4 4 h h 4 4 4 4 4 a 2 4 4 Reactor Manual Control 2

_4 4 4 4 4 CR 4 4 4 4 4 4 4 4 4 4 CRD Hydraulic System 4 4 JNon-S(RAM) RB 4 4 a Safety / Relief Valve 2 4 ,_ 2 4 4 4 4 4 4

_Sys. (Non-ADS) DW/RB 3 3 3 4 3 3 4 3 3 4 4 4 Recirculation System ePumps DW 2 2 4 4 2 4 4 2 evalve & Operators 2_ 4 4 4 DW 2 2 4 4 2 4 4 2 2 4 4 4 eMG Sets TB/RB d 4 4 4 4 4 4 4 4 4 4 4 eMCC TB/RB 4 4 4 4 4 4 4 4 4 4 4 4 eFlow Control CR/RB 4 4 4 4 4 4 4 4 4 4 eControTTns t. 4 4 Transmitters RB 4 4 4 4 4 4 4 4 4 4 4 4

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