ML17317B402
| ML17317B402 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 06/22/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17317B401 | List: |
| References | |
| NUDOCS 7908030559 | |
| Download: ML17317B402 (3) | |
Text
DONALD C.
COOK NUCLEAR PLANT UNITS 1
AND 2 REVIEW OF PIPING'EANALYSIS PER I&E BULLETIN 79-07 SAFETY EVALUATION REPORT ENGINEERING BRANCH DIVISION OF OPERATING REACTORS INTRODUCTION/BACKGROUND In their April 24,
- 1979, response to I&E Bulletin 79-07, American Electric Power Service. Corporation (AEP) identified 24 lines that had originally been analyzed using an earlier version of the WESTDYN computer program that incorporated an algebraic sum of intramodal responses to seismic loadings.
- However, 19 out of these 24 lines had subsequently been reanalyzed using absolute summation or SRSS method.
By letter dated May 4, 1979, the licensee (AEP) reported that a further check of their records showed that 23 of the 24 lines had previously been'reanalyzed.
In response to NRC questions discussed during telephone conversations, AEP supplied supplemental information on this subject in a letter dated June 20; 1979.
DISCUSSION The licensee identified the only line that had'not been seismically reanalyzed was the 14"-pressurizer surge line.
This line has the same geometry.on both units, but in opposite hand, therefore, only one stress analysjq was necessary.
AEP has stated that a reanalysis of the surge line in the "as-built" condition has been completed and the results show all piping stresses remain below their allowable values, as specified in the FSAR's.
Additionally, the pipe supports meet FSAR criteria and the nozzle loads have been found acceptable.
This piping run was reanalyzed by Westinghouse using their current version of WESTDYN which combines the intramodal responses by absolute summation.
The licensee's response to I&E Bulletin 79-04 also states that no VELAN swing check valves are in this piping.
I&E Bulletin 79-02 was not addressed at this time.
The licensee has stated that the reanalysis has no effect on pipe break criteria since break locations were not postulated based on stress levels.
EVALUATION The reanalysis technique employed was a lumped mass response spectra modal
'nalysis.
This dynamic analysis procedure is an acceptable method.
The absolute
combination of responses in two directions is consistent with the Staff Position and, therefore, is also acceptable.
Results of the reanalysis show that the pipe stresses are below their allowable
- values, as specified in the
Also, Westinghouse has determined that the new nozzle loads imposed by the 14" surge line on the pressurizer are acceptable since they are bounded by-the loads previously used in the stress analysis of the pressurizer pp~k'c.zD~ s9 (p
nozzle.
Therefore, we find the results of the reanalysis acceptable.
Since the supports involved do not utilize concrete expansion anchor bolts, the licensee did not need to consider IEE Bulletin 79-02.
Further, their response concerning IEE Bulletin 79-04 states that no VELAN swing check valves are in these lines.
The reanalysis has no effect on the Cook 1 or 2 pipe break criteria.
Code Verification The computer listing of the dynamic portion of WESTDYN which performs the response spectrum analysis and modal combinations has been reviewed by the staff; statements regarding the intramodal-and intermodal combinations have been verified and found acceptable.
In addition, Westinghouse has also committed to solve a set of benchmark problems and to provide the NRC a
problem for confirmatory analysis.
They have agreed to submit this commitment in writing to the NRC by tune 26, 1979.
We find this response acceptable.
CONCLUSION Based on the discussion and eva'1uation presented
- above, we conclude that the requirements set forth in I8E Bulletin 79-07 are satisfied.
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