ML17325A405
| ML17325A405 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 10/29/1987 |
| From: | Wigginton D Office of Nuclear Reactor Regulation |
| To: | Dolan J AMERICAN ELECTRIC POWER SERVICE CORP., INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| References | |
| GL-83-28, NUDOCS 8711030430 | |
| Download: ML17325A405 (4) | |
Text
October 29, 1987 l
Docket Nos.
50-315 and 50-316 Mr. John Dolan, Vice President
'Indiana and Michigan Power Company c/o American Electric Power Service Corporation 1 Riverside Plaza
- Columbus, Ohio 43216
'ear Mr. Dolan:
DISTRIBUTION:
NRC PCR~'
Local PDR PDI II-3 r/f DWigginton GHolahan PKreutzer OGC-Bethesda EJordan JPartlow ACRS(10)
PDIII-3 Gray File By [[letter::05000316/LER-1987-007-01, :on 870714,ESF Reactor Trip Occurred Due to Undervoltage of Reactor Coolant Buses.Caused by Failure of Main Generator Voltage Control Sys.Failed & Suspected Components of Sys Replaced|letter dated August 13, 1987]] the Indiana and Michigan Power Company responded to a request for additional information regarding item 4.2, parts 3 and 4 of Generic Letter 83-28.
We are nearing completion of our review of this item and need clarification or additional information as detailed in Enclosure.
This was discussed with your staff.
Please provide the requested information or a schedule for submittal within 30 days.
If further discussion is needed to close this issue out, please let us know.
Sincerely,
Enclosure:
As stated
/~/
David L. Wigginton, Acting Director Project Directorate III-3 Division of Reactor Projects cc:
See next page Office:
LA/PDIlg'-3 Surname:
PKreutzer Date:
10@)/87 PM II-3 DWigginton 10/P/87 87ii030430 871029 PDR
. ADOCK 050003iS NOR
Mr. John Dolan Indiana and Michigan Electric Company Donald C.
Cook Nuclear Plant CC:
Mr. M. P. Alexich Vice President Nuclear Operations American Electric Power Service Corporation 1 Riverside Plaza
- Columbus, Ohio 43215 Attorney General Department of Attorney General 525 West Ottawa Street Lansing, Michigan 48913 Township Supervisor Lake Township Hall Post Office Box 818 Bridgeman, Michigan 49106 W.
G. Smith, Jr., Plant Manager Donald C.
Cook Nuclear Plant Post Office Box 458 Bridgman, Michigan 49106 U.S. Nuclear Regulatory Commission Resident Inspectors Office 7700 Red Arrow Highway Stevensville, Michigan 49127 Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 2300 N Street, N.W.
Washington, DC 20037 Mayor, City of Bridgeman Post Office Box 366 Bridgeman, Michigan 49106 Special Assistant to the Governor Room 1 - State Capitol Lansing, Michigan 48909 Nuclear Facilities and Environmental Monitoring Section Office Division of Radiological Health Department of Public Health 3500 N. Logan Street Post Office Box 30035 Lansing, Michigan 48909
/
Regional Administrator, Region III U.S. Nuclear Regulatory Commission 799 Roosevel t Road Glen El lyn, I 1 1 inoi s 60137 Mr. J. Feinstein American Electric Power Service Corporation 1 Riverside Plaza
- Columbus, Ohio 43216
RE UEST FOR ADDITIONAL INfORMATION ITEM 83-28 N
NUL Uh
,2 Item 4.2 of Generic Letter 83-28 requires licensees or applicants to describe their preventative maintenance and surveillance program for ensuring reliable reactor trip breaker (RTB) operation.
Parts 3 and 4 of Item 4.2 pertains to life testing of an acceptable sample size of the breakers, and periodic re-placement of the breakers or components consistent with demonstrated life cycles.
The licensee submitted a response by [[letter::05000316/LER-1987-007-01, :on 870714,ESF Reactor Trip Occurred Due to Undervoltage of Reactor Coolant Buses.Caused by Failure of Main Generator Voltage Control Sys.Failed & Suspected Components of Sys Replaced|letter dated August 13, 1987]], to staff's March 9, 1987 request for additional information.
Staff's principle concerns in the March 9, 1987 request for additional informa-tion was with respect to possible cyclic and non-cyclic age-related failures of the RTB itself and non-cyclic age-related failures of the undervoltage trip attach-ment (UVTA) and shunt trip attachment (STA).
Staff accepted WCAP-10852 as ade-quately addressing the cyclic life of the UVTA and STA.
The licensee states that the portions of the RTB mechanism that perform a safety function are composed of metallic parts which have a life that greatly exceeds the expected life of the plant, with mechanical wear being the only limiting factor.
No statistical or test data was furnished to support that the life of the RTB exceeds the life of the plant.
The licensee notes that although the RTB closing coil and control relay are not wholly metallic, these components do not participate in the tripping sequence and therefore serve no safety function.
Similarly, the licensee states that although the holding coil of the UVTA is susceptible to thermal aging effects, this device is inherently fail safe in that the failure of the coil results in a reactor trip.
The possibility that the above components or other components could disintegrate and interfere with the tripping function is not addressed.
The licensee states that the STA is normally deenergized and not prone to ac-celerated degradation due to thermal aging effects.
However, staff is aware that the STA is subjected to relatively high momentary currents, as compared to its continuous current rating, during testing and upon demand energization.
In response to the staff's question on what action would be taken upon any future failure of the RTB, the licensee gave as an example the actions taken after a
previous failure in 1985.
No commitments were made with respect to future failures that may occur.
Based upon the above considerations, the staff concludes that the licensee should (1) provide documentation to support their contention that the cyclic life of the reactor trip breaker (RTB) exceeds the RTB's cyclic requirements over its lifetime, and (2) commit, for any future failure of the RTB to trip, either during testing or upon demand, to make a determination of whether the fai lure could have been age-related, and if so, to assume that the failure was age-
- related, and to take appropriate action accordingly.