ML17333A231
| ML17333A231 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 12/13/1995 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17333A230 | List: |
| References | |
| NUDOCS 9512190283 | |
| Download: ML17333A231 (3) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 205S&4001 SAFETY EVALUATIO BY T E OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AHEND NT 0.
204 TO FACILITY OPERATING LICENSE NO. DPR-58 AND AHENDNE T NO. >89 TO FACILITY OPERATING LICENSE NO.
DPR-74 INDIANA HICHIGAN POWER COHPA Y
DONA D C.
COOK UCLEAR PLANT UNIT NOS.
1 AND 2 DOCKET NOS. 50-315 AND 50-316
- 1. 0 INTRODUCTION By letter dated Hay 25, 1995, the Indiana Hichigan Power Company (the licensee) requested amendments to the Technical Specifications (TS) appended to Facility Operating License Nos.
DPR-58 and DPR-74 for the Donald C.
Cook Nuclear Plant, Unit Nos.
1 and 2.
The proposed amendments would modify TS Table 4.3-2 to change the surveillance frequency for the manual actuation function for main steam line isolation.
The surveillance frequency would be changed from monthly to quarterly.
- 2. 0 EVALUATION The design of the main steam isolation valves (HSIVs) at Cook includes a
piston which is attached to the valve stem.
The steam above and below the piston is normally at line pressure.
The cylinder volume above the piston is piped through a three-way valve into a pair of redundant, air operated dump valves.
Upon receipt of a signal to close, the dump valves open and vent the steam from the cylinder.
The steam pressure in the valve body below the piston forces the piston to move rapidly and close the valve.
Due to the nature of this design the manual switch for NSIV actuation constitutes an open/close control for the dump valve (there are two switches per NSIV, one for each dump valve, eight total).
When it is switched, the dump valve opens, causing the NSIV to close.
As a result, the manual actuation for the HSIV is different from the other Engineered Safety Feature Actuation Systems (ESFAS) manual functions in that it bypasses the Solid State Protection System.
Therefore, the functional testing of the manual ESFAS steamline isolation function is just a stroke test of the dump valves.
Currently, the Cook TS require functional testing of the manual actuation function for the HSIVs on a monthly basis.
To perform this testing, the three-way valve is positioned to isolate one dump valve at a time.
One manual switch is tested at a time to ensure the dump valve opens.
This manual actuation is the same as quarterly tests done per ASNE Section XI.
9512190283
'751213 PDR ADQCK 050003i5 P
The licensee has proposed to change the required HSIV surveillance from monthly to quarterly.
The licensee provided the following justification for the change:
1.
Based on previous, test data, the system has proven itself to be reliable.
Since
- 1988, over 1,300 tests have been conducted, with only 3 failures.
These failures involved minor mechanical problems and were corrected expeditiously.
Furthermore, the last such failure occurred in October
- 1991, indicating over 3 years of testing without failure.
The excellent performance record of this system gives us confidence that quarterly testing is sufficient.
- 2. The change achieves consistency between the ASME Section XI requirements for the dump valves and the T/S required testing.
- 3. In February 1994, unit 2 tripped due to closure of one of the MSIVs.
The trip occurred following return of a dump valve to service following maintenance to correct seat leakby.
The dump valve actuator had been improperly recoupled to the valve, which ultimately resulted in closure of the HSIV.,
Following the trip...[the licensee]...concluded that monthly testing of the dump valves was not only unnecessary, but also risky for several reasons:
(1) each cycling of the dump valve avails the valve to seat damage.
This damage can then lead to seat leakby and subsequent maintenance. which requires an LCO entry and involves further plant jeopardy; (2) test history has identified numerous incidents of HSIVs drifting off of their full open seats during testing; and (3) excessive leakage past the three-way valve could cause the MSIV to close, tripping the unit.
The staff has reviewed the licensee's considerations and agrees that the current testing is unnecessarily frequent.
The proposed test frequency is consistent with, or more frequent, than the requirements approved for other facilities and the improved Standard Technical Specifications Westinghouse
- Plants, NUREG-1431.
Based on the above, the proposed change in surveillance frequency is acceptable.
The licensee has also proposed to delete a footnote associated with the MSIV channel functional test surveillance requirement.
The footnote currently states that "Manual actuation switches shall be tested at least once per 18 months during shutdown.
All other circuitry associated with manual safeguards actuation shall receive a
CHANNEL FUNCTIONAL TEST at least once per 31 days."
As previously stated, the channel functional test is initiated with the manual switch.
Since the manual switches are tested as part of the channel functional test, the footnote is unnecessary and the deletion is acceptable.
Finally, the licensee has proposed to delete a footnote on page 3/4 3-32 of Unit 2's TS which related to surveillance extensions for a past outage.
Since the outage has been completed and the extensions are no longer applicable, the staff finds this administrative change to remove an obsolete footnote acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Michigan State official was notified of the proposed issuance of the amendments.
The State official. had no comments.
- 4. 0 ENVIRONMENTAL CONSIDERATION The amendments change surveillance requirements.
The staff has determined that the amendments involve no significant increase in the
- amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no public comment on such finding (60 FR 35081).
Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed
- above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
John B. Hickman, NRR Date:
December 13, 1995