ML20154R159

Responds to NRC Bulletin 88-008, Thermal Stresses in Piping Connected to Rcs

ML20154R159
Person / Time
Site:	Brunswick
Issue date:	09/28/1988
From:	Mcduffie M CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
IEB-88-008, IEB-88-8, NLS-88-236, NUDOCS 8810040185
Download: ML20154R159 (3)

Text

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i l United States Nuclear Regulatory Commission t ATTENTION: Document Control Desk l Washington, DC 2035)

BRIJNSWICK STEAM ELECTRIC PLANT, UNIT NOS.1 AT4D 2 DOCKET NOS. 50-325 & $0-324/ LICENSE NOS. DPR-71 & DPR-62 i

RESPONSE TO NRC BULLETIN 88-08 Gentlemen:

Carolina Power & Light Company hereby submits information requested by NRC Bulletin 88 08, "Thermal Stresses in Piping Connected to Reactor Coolant Systems," for i the Brunswick Steam Electric Plant, Units I and 2 (BSEP). This bulletin requested that f licensees review their reactor coolant systems to identify any connected, unisolable t piping that could be subjected to temperature distributions, which would result in l unacceptable thermal stresses, and take action, where such piping is identified, to ensure j that piping will not be subjected to unacceptable thermal stresses. The BSEP response to the specific action requested by this bulletin is attae'ied. [

t if you have any questions concerning this response or require additional information, t l please contact Mr. L.1. Lollin. [

r Yours very truly,  !

// A 'O[

M. A. McDuffie  !

l JitE/lah ($470]IlE)

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cca Dr. J. Nelson Grace i Mr. W.11. Rutand '

Mr. B. C. Buckley M. A. McDuffie, having been first duly sworn, did depose and say that the information l contained herein is true and correct to the best of his information, knowledge and belief  ;

and the sources of his information are of ficers, employees, contractors, and agents of  ;

Carolina Power & Light Company. ' ,,o* " ""'"'s i n h hotan 7 ~ Notary (Seal) 7 I s, g fV[ NOTARY) i i My commission expires // -

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ACTION 1 Review systems connected to the RCS to determine whether unisolable sections of piping connected to the RCS can be subjected to stresses from temperature stratification or temperature oscillations that could be induced by leaking va ves and that were not evaluated in the design analysis of the piping. For those addressees who determine that there are no unisolebte sections of piping that can be subjected to such stresses, no additional actions are requested except for the report required below.

BSEP RESPONSE Carolina Power & Light Company has com ?leted an evaluatlon of the systems connected to the RCS at BSEP and determined that t1ere are no unisolable pl> lng systems that have the potential for inducing unacceptable thermal stresses as definec in NRC Bulletin 33-03.

In a boiling water reactor like BSEP, the high pressure systems connecting to the RCS are the Reactor Core Isolation Cooling (RCIC) System, the fligh Pressure Coolant Injection (llPCI) System, the Standby Liquid Control (SLC) System, the Reactor Water Cleanup (RWCU) System, and the Feedwater (FW) System. In addition, during certain modes of normal operation, the Residual Heat Removal (RilR) System and the Core Spray (CS) System have the potential to inject relatively cold water into the RCS.

}{PCI The !!PCI System is at a higher pressure than the RCS when the itPCI System is in operation liowever, during normal plant operation, the llPCI System is operated infrequently, primarily for surveillance testing. Because leakage from the liPCI System to the RCS can only occur when the fiPCI System is operating and IIPCI System operation is infrequent, the thermal fatigue stresses induced by any leakage would be insignificant.

RCIC Like the !!PCI System, the RCIC System is at a higher pressure than the RCS when the RCIC System is in operation. Also like tiie llPCI System, the RCIC System is operated infrequently and the thermal fatigue stresses induced by potential leakage are insignificant.

SLC The SLC System operates at a higher pressure than the RCS pressure, and, thus, has the capability to inject cold water to the reactor. Like the llPCI System and the RCIC System, the system is only operated Infrequently, in addition, the system is isolated from the RCS by explosive type (squib) valves. Due to the positive isolation characteristics of these valves and the infrequent nature of system operation, the SLC System is not a source (,f thermal fatigue stress.

RWCU The RWCU System is in continuous operation during all phases of reactor operation. Additionally, the system is designed to process water with a minimum heat loss in that the water is reheated prior to injection to the FW System. No unanticipated thermal fatigue stresses are introduced in this system.

(5470#E/ tan)

FW The FW System is in continuous operation during normal reactor operation. In addition, the FW System is reheated prior to injection to the reactor. The system is designed for the temperature transients encountered. No unanticipated thermal f atigue stresses are introduced in this system.

CS and RHR Both the CS System and the RHR System operate at pressures less than normal RCS pressure. The only time these systems could leak cold water to the RCS is when RCS pressure is below system punip shutoff head. Because this situation is relati.vely infrequent, thermal fatigue stress is not a problem in these systems.

Based on the above analysis, BSEP has no unisolable sections of piping that will be subjected to excessive thermal fatigue stresses as defined in NRC Bulletin 88-08.

Accordingly, no further action is required.

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