ML19332B968
| ML19332B968 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/17/1989 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-88-008, IEB-88-8, TXX-89805, NUDOCS 8911220129 | |
| Download: ML19332B968 (4) | |
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Ref. # NRCB 88-08 nlELECTRIC November 17, 1989 OaW$NN U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 NRC BULLETIN 88 08: INTERIM RESPONSE TO THERMAL STRESSES IN PIPING CONNECTED TO REACTOR COOLANT SYSTEMS REF: TU Electric letter TXX-88766, W. G. Counsil to NRC dated October.31, 1988 Gentlemen:
The referenced letter provided TU Electric's response to Reporting Requirement 1 of NRC Bulletin 88-08, " Thermal Stresses in Piping Connected to Reactor Coolant Systems." The TV Electric response identified four sections of unisolable )iping that are potentially susceptible to the phenomena described by tie Bulletin, and confirmed that Action 2 (i.e., NDE cf piping subject to excessive thermal stresses) and Action 3 (i.e., pro 0 rams for continued assurance) would be completed prior to initial criticality of the respective CPSES units. The response also confirmed that, within 30 days of completing Actions 2 and 3, a letter describing the actions taken would be submitted in accordance with Reporting Requirement 2.
I In response to a verbal request from the NRC staff, this letter provides an interim response to Reporting Requirement 2 for Unit 1.
The attachment provides the required affidavit in accordance with the requirement of NRC Bulletin 88-08 that responses be submitted under oath or affirmation under the provisions of Section 182a,-Atomic Energy Act of 1954, as amended.
TU Electric's final response to Reporting Requirement 2 for Units 1 and 2 will be submitted in accordance with NRC Bulletin 88-08 requirements.
For clarity, L
Reporting Requirement 2 and Actions 2 and 3 have been restated.
Reportino Reauirement 2 Those addressees who determine that there are unisolable sections of piping that can be subjected to stresses from temperature stratification or temperature oscillations that could be induced by leaking valves and that were not evaluated in the design analysis of the piping shall submit a letter within 30 days of conpletion of Actions 2 and 3.
This letter should confirm that Actions ? and 3 have been completed and describe the actions taken.
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Page 2 of 3 Action 2 For any unisolable sections 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 j
existing flaws.
TU ELECTRIC RESPONSE TO ACTION 2 Based on a crack initiation and propagation analyses for Farley Unit 2, TU Electric and Westinghouse have determined that it is highly unlikely that a crack could be initiated by thermal fatigue during the relatively short amount of time that Unit I has been hot.
Therefore, the nondestructive examination j
requirements of Action 2 are not considered applicable to CPSES Unit 1.
1 Action 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 J
during the remaining life of the unit. This assurance may be provided by (1) redesigning and modifying these sections of piping to withstand combined 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 t
ensuring that pressure upstream from block valves which might-leak is monitored and does not exceed RCS pressure.
l TV ELECTRIC RESPONSE TO ACTION 3 TV Electric plans to utilize the second option described by Action 3 above.
Resistance Temperature Detectors (RTDs) will be installed on the four unisolable piping sections described in the referenced letter. The RTDs will measure pipe temperatures at selected locations on the piping.
Plant parameters such as reactor coolant > ump status, reactor coolant pressure, and pressurizer spray status will also )e monitored. Data will be periodically evaluated for indications of unacceptable thermal stratification.
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4 TXX-89805 November 17, 1989 i
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The above program is based on TV Electric's understanding of Industry and Owner's group initiatives currently in process to address the concerns of NRC i
Bulletirt ES-08.
Preparation of site procedures and installation of hardware in support of the monitoring program is currently in progress.
Sincerely, e-William J. Cah 1, Jr.
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HAM /vid Attachment c - Mr. R. D. Martin, Region IV
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Resident Inspectors, CPSES (3)
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Attachment to TXX-89805 UNITED STATES OF AMERICA NUCLEAR RE'JULATORY COP 9tISSION In the Matter of Texas Utilities Electric Company
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Docket Nos. 50-445 50-446 (Comanche Peak Steam Electric Station, Units l'& 2)
AFFIDAVIT William J. Cahill, Jr. being duly sworn, hereby deposes and says that he is Execstive Vice President, Nuclear of TU Electric, the lead Applicant herein; that he is duly authorized to sign and file with the Nuclear Regulatory Commission this supplementary response to NRC Bulletin 88-08; that he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge, information and belief.
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A WilliamJ.Cayl) President,g' Nuclear i, Jf. "
Executive Vi W 1
r STATE OF TEXAS
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COUNTY OF SoMERVELL
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Subscribed and sworn to before me, a Notary Public, on this ista day of 1989.
November
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Notary Public PATRICIA WILSON MY COMMt4CN (XPF.ES March 16,1993 4.
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