ML16341F325
| ML16341F325 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 09/07/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML16341F324 | List: |
| References | |
| NUDOCS 8909210078 | |
| Download: ML16341F325 (6) | |
Text
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'UCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON POWER PLANT - UNIT I DOCKET NO. 50-275 SCHEDULAR RELIEF FROM CERTAIN INSERVICE INSPECTION RE UIREMENTS
1.0 INTRODUCTION
By letter dated September 5, 1989, Pacific Gas and Electric Company, the 1icensee for Diablo Canyon Power Plant Units I and 2, requested schedular relief for Unit I from certain ASME Code Section XI Inservice Inspection requirements.
It was only recently realized that these tests could not be performed with the reactor operating without undue risks due to ALARA, personnel
- safety, containment integrity, and core reactivity change considerations.
To perform the tests without these risks, plant shutdown would be necessary, involving cycling of systems and corresponding wear and plant life cost which would exceed the insignificant increment in safety gained by performing the tests within the current schedule as opposed to deferring the tests for 60 days as requested.
The licensee therefore requested a one-time schedular relief of 60 days in order to perform the tests during the upcoming refueling outage, currently scheduled to begin October 13, 1989.
Our evaluation of the licensee's relief request is provided below.
2.0 EVALUATION The licensee proposed a one-time relief request, a 60-day extension of the ASME Boiler and Pressure Vessel Code Section XI 3 I/3 year (plus one year extension allowed by IWA-2400) time period requirement to allow performance of visual inspection of piping and welds in portions of several systems that are inaccessible while the reactor is operating.
The relief would allow the inspections to be performed during the upcoming refueling outage, scheduled to begin October 13, 1989.
Following is a description of each system or component affected by this
- request, a description of the Code Class and Applicable Code Requirement, the basis for requesting relief, and a recitation of testing done in lieu of ISI requirements being deferred.
(I)
Containment S ra Dischar e Pi in (Code Class 2); applicable Co e Requirement 1 WC-5221 The basis for requesting relief are ALARA considerations and containment integrity.
Performance of the tests per ISI schedule would require plant shutdown.
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Testing done in lieu of ISI requirements include STP V-630, STP M-7, and STP V-17, surveillance test procedure performed on an ongoing basis since commercial operation of Unit 1.
(2)
Boron Ins ection Tank Dischar e/Safet Injection Test Pi in Co e C ass; app sea e
o e equlrement C-The bases for requesting relief are ALARA considerations and potential reactivity changes.
Performance of the tests per ISI schedule would require plant shutdown.
Testing done in lieu of ISI requirements include STP V-651 and STP M-7, surveillance test procedures performed on an ongoing basis since commercial operation.
(3)
Nitro en to Steam Generator s Pi in (Code Class 2; applicable o e equsrement I
C-1 a
The bases for requesting relief are ALARA considerations and containment integrity.
Performance of tests per ISI require-ments would require plant shutdown.
Testing done in lieu of ISI requirement includes STP M-7, performed on an ongoing basis since commercial operation.
(4)
Com onent Coolin Water Pi in (Code Class 3; applicable Code Requirements IWD-5221 an 1WD-5222).
The basis for requesting relief is ALARA considerations.
Performance of tests per ISI requirements would require plant shutdown.
No testing will be done in lieu of ISI requirements.
For each of the four aforementioned
- cases, the relief requested is a
one-time 60-day extension beyond September 7,
1989 to allow the tests to be performed during the unit upcoming refueling outage scheduled for October 13, 1989.
The staff has reviewed the licensee's schedular relief request and finds that the granting of the requested relief is authorized by law, will not present an undue risk to the public health and safety, will not endanger life or property and is consistent with the common defense and security, and is otherwise in the public interest giving due consideration to the adverse consequences of not granting the relief.
The staff finds also that the requested 60-day extension is not a significant deviation from Code requirements based on the fact that the licensee has found no history of problems or failures with similar piping and welds.
3.0 CONCLUSION
Based on the above discussion, the staff concludes that, considering the burden on the licensee of shutting down the plant and the minimal safety implications of extending the test interval a maximum of 60 days, the one-time schedular relief for the affected four systems should be granted as requested.
The requested relief is granted.
Princi al Contributor:
Roby Bevan pate:
Septemhr 7,
1989
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