U-601492, Responds to Suppl 3 to NRC Bulletin 88-008, Thermal Stresses in Piping Connected to Rcs. Several Sys,Including Lpcs,Hpcs & Rhr,Identified Which Could Be Subj to Thermal Stratification,Per Action 1.Actions 2 & 3 to Be Addressed

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Responds to Suppl 3 to NRC Bulletin 88-008, Thermal Stresses in Piping Connected to Rcs. Several Sys,Including Lpcs,Hpcs & Rhr,Identified Which Could Be Subj to Thermal Stratification,Per Action 1.Actions 2 & 3 to Be Addressed
ML20246C338
Person / Time
Site: Clinton Constellation icon.png
Issue date: 08/17/1989
From: Hall D
ILLINOIS POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
DPH-0506-89, IEB-88-008, U-601492, NUDOCS 8908240333
Download: ML20246C338 (2)


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, /. 2 **- U-601492 L30-89 ( 08-17 )-LP 8G.130 ILLINO/S POWER COMPANY CLINTON POWER STATION. P.O. B01( 678. CLINTON. ILLINOIS 61727 DPH-0506-89 August 17, 1989 Docket No. 50-461 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555

Subject:

Clinton Power Station ResDonse to BulletiD 88-08 SuoDiement 3

Dear Sir:

This letter is in response to Bulletin 88-08 Supplement 3, " Thermal Stresses in Piping Connected to Reactor-Coolant Systems". In response to Action 1 of the Bulletin, Illinois Power Company (IP) reviewed all piping systems connected to the Reactor Coolant System (RCS) and determined that several systems, including Low Pressure Core Spray, High Pressure Core Spray.and Residual Heat Removal, could be subject to

' thermal' stratification. IP is in the process of performing

a. detailed review of all unisolable sections of piping connected to the reactor coolant system to identify other possible cases where temperature stratification or thermal fatigue could occur. Following this-review, we will proceed, as. appropriate with Actions 2 and 3 of Bulletin 88-08.that states:
2. For any unisolable section'of piping connected to the RCS that may have been subjected to excessive thermal stresses, examine nondestructively the welds, heat-affected zones and high stress locations, including geometric discontinuities, in that piping to provide assurance that there are no existing flaws.

'3 . Plan and implement a program to provide continuing assurance that unisolable sections of all piping connected to the RCS will not be subjected to combined cyclic and static thermal and other stresses that could cause fatigue failure during the remaining life of the unit. This assurance

.may be provided by (1) redesigning and modifying these sections of piping to withstand combined plb i ,

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  • stresses caused by various loads including temporal and spatial distributions of temperature resulting from leakage across valve seats, (2)

' instrumenting this piping to detect adverse temperature distributions and establishing appropriate limits on temperature distributions, or.(3) providing means for ensuring that pressure

! upstream from block valves which might leak is monitored and does not exceed RCS pressure.

IP will notify the NRC by February 17, 1990, of the' detailed review results, and provide a proposed schedule for implementing any required actions.

I hereby affirm that the information in this letter is correct to the best of my knowledge.

Sincerely yours,

. . Hall Senior Vice President REL/krm cc: NRC Clinton Licensing Project Manager NRC Resident Office Regional Administrator, Region III, USNRC Illinois Department of Nuclear Safety i

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