ML20214V891
| ML20214V891 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 06/04/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20214V889 | List: |
| References | |
| NUDOCS 8706120365 | |
| Download: ML20214V891 (2) | |
Text
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION E
WASHINGTON D. C. 20565 o
k..... j-SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION UNION ELECTRTC~EEEPANY
_ALLAWAY PLANT C
DOCKET NO. 50-483 RELIEF FROM CERTAIN INSERVICE TESTING REQUIREMENTS
1.0 INTRODUCTION
By letter dated May 28, 1987, the Union Electric Company, the licensee for the Callaway Plant, requested an emergency relief from certain Inservice Testing (IST) requirements.
According to ASME Code,Section XI, requirements as implemented by the i
Technical Specifications, certain normally closed check valves must be tested for leakage as well as struked to the full open position at certain cold shutdowns. Recently, the licensee found that four check valves might not have been stroked to their open position during its last cold shutdown.
To do the said test, a plant shutdown would be necessary. Since the licensee does not think that a plant shutdown is justified for the sole purpose of doing the valve testing, a relief is requested to postpone the test to the next cold shutdown or refueling cutage, whichever comes first.
Our evaluation of the licensee's relief request is provided below.
2.0 EVALUATION r
The Code of Federal Regulations,10 CFR 50.55a, requires, in part, that certain check valves be tested in accordance with the ASME Section XI 1
requirements.Section XI in turn requires that check valves be exercised at least every 3 months. However, valves that cannot be exercised during l
plant operation shall be full-stroke exercised during cold shutdowns.
From this requirement, the four check valves (BB-89498, C, and EJ-8841A, B) on the residual heat removal (RHR) injection lines to the hot leg con-nections are required to be tested at certain cold shutdowns.
In the relief request, the licensee indicated that the above valves might not have been tested in the open direction during its last cold. shutdown outage.
1 In order to continue power operation, the missed tests must be perfonned to fulfill the TS surveillance requirements. Suce testing of these valves requires a plant shutdown, the licensee requested a relief to extend the test interval of the affected valves from the last cold shutdown to the next coming cold shutdown or refueling outage, whic.5ever comes first.
To support its relief request, the licensee stata d t'tah (1) there are other similar valves that were testrd at longer refueling outage intervals than cold shutdown intervals; (2) there was no aistuy of failures or problems with these similar valves; and (3) since no failures or problems had occurred, the added margin of safety by doint the test does not justify the adverse effect of a plant shutdown.
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5 2-Although the intent of ASME Code Section XI is to test all valves covered p
by the IST program quarterly, it clearly does not require a plant shutdown j
to do quarterly valve testing for those valves that cannot be tested at power.. The ASME Code also recognizes.that the test intervals for certain valves can be. varied widely without significant impact on plant operation.
Furthermore, our review it.dicates that the function of these four affected valves is'to open to inject coolant to the reactor through two hot leg 7
. connections. :The injection pugpose is to provide back flow to flush the L
core during the long term core cooling following a major loss-of-coolant accident'(LOCA) event.- It should be noted that the hot leg injection 6
function is not needed imediately following a LOCA.
Furthermore, there
.are other: alternative. flow paths that can deliver coolant to all hot leg connections. Therefore, the safety significance of granting the relief M
from not-testing and not knowing the status of these affected valves for a g
few more months appears to be not significant.
The licensee requested relief to postpone the required test to the next shutdown or refueling outage. Since the next refueling outage is currently scheduled for September 1987, assuming no cold shutdown between now and the next refueling outage, the longest time for which relief would be granted would be about 4 months. The 4-months extension for the test is not a significant deviation from Code requirements based on the fact that the licensee found no history of failures or problems on similar valves.
3.0 CONCLUSION
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,w 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 4 months, the one-time emergency relief for the affected four valves should be granted as requested. Granting this one-time relief is authorized by law and will not endanger life or property or the comon defense and security and is otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.
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