ML17334B056
| ML17334B056 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 03/09/1987 |
| From: | Youngblood B 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 8703110305 | |
| Download: ML17334B056 (8) | |
Text
Docket Nos.:
50-315 and 50-316 Mr. John Dolan, Vice President Indiana and Michigan Electric Company c/o American Electric Power Service Corporation 1 Riverside Plaza
- Columbus, Ohio 43216
Dear Mr. Dolan:
We have reviewed the Indiana and Michigan Electric Company submittal dated April 22, 1986 (AEP:NRC 08389) regarding the ATWS Items 4.2.3 and 4.2.4 on life testing of the reactor trip breakers.
Our contractor's Technical Evaluation Report is enclosed and we are in agreement with the conclusion.
However, since appropriate alternatives may be available to IMEC for reso-lution of these items, it is requested that IMEC reconsider the life testing concern.
Within 60 days of receipt of this letter, it is also requested that IMEC provide a schedule or commitment to an appropriate program.
If there are any questions on this matter, please let us know.
Sincerely,
Enclosure:
As stated cc:
See next page
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s Vr. 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
<8913 Township Supervisor Lake Township l'all 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 Coomission 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 The Honorable John E. Grotberg United States House of Reprieve>>tatives l'ashington, DC 20515 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen El lyn, Illinois 60137 J. Feinstein American Electric Power Service Corporatior 1 Riverside Plaza
- Columbus, Ohio 43216
INPUT FOR SAFETY EVALUATION REPORT D.
C.
COOK 1
AND 2 REACTOR TRIP SYSTEM RELIABILITY ITEMS 4. 2.
~
AND 4. 2. 4 OF GENERIC LETTER 83-28 1.
INTRODUCTION On July 8, 198K, the Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 8i-28.
Item 4.2 of this letter required the licensees and applicants to submit a description of their preventive maintenance and surveillance program to ensure reliable reactor trip breaker operation.
The description of the submitted program was to include the following:
GL, Item 4.2.3 Life testing of the breakers (including the trip attachments) on an acceptable sample size.
GL, Item 4. 2. 4 Periodic replacement of breakers ot'omponents consistent with demonstrated life cycles.
Indiana and Michigan Electric Company (18<MEC), the licensee for D.
C.
Cook 1 and 2, submitted a response to Items 4.2.3 and 4.2.4 of the Generic Letter on April 22, 1986.
This report presents an evaluation of the a'dequacy of that response and of the licensee's life testing and periodic replacement programs for RTBs.
2.
EVALUATION CRITERIA
- 2. 1 Life Testin Pro ram The requirement for life testing of the RTBs's specified by Item 4.2.3 of the Generic Letter.
The purpose of the Iife testing i s to identi fy a Qual ified 1 ife for the RTB or any of its replaceable components as required by 10 CFR 50.55a(h).
By definition qualified life is the period of time for which satisfactory performance can be demonstrated for a specific set of service conditions.
The qualification methods that can be used to determine the qualified life, including the effects of aging, are identified in IEEE 4
~<<
I t
Standard
<<2~-1974.
IEEE Standard 32i-1974 provides guidance on aging based on an awareness that the ability of Class 1E equipment to perform its safety function may be affected by changes due to natural, operational, and environmental phenomena over time.,
The concept of aging was addressed explicitly for the first time in IEEE Standard i23-1974.
The aging guidance therein reflects the requirement of IEEE Standard
- 279, which is the Standard specifically mentioned in 10 CFR 50.55a(h).
Conformance with IEEE Standard 32~-1974 is a method, acceptable to the staff, of meeting the requirements of 10 CFR 50. 55a (h).
If it can be demonstrated that the qualified life exceeds the life of the Generating Station, then the specific qualified life need not be identified.
In a practical sense the intent of the life testing requirement of the generic letter would be satisfied by demonstrating that the qualified life of the breaker (for the tripping function) exceeds the expected use projected to the next refueling.
Cycle testing by the various Owners
- Groups, although it does not consider the effects of aging, may provide evidence to support continued use of the RTBs for one additional refueling cycle, provided that the individual breaker has not shown any sign of degradation in the licensee's Parametric Trend Monitoring Program.
In this approach the actual qualified life is not specifically identified but only demonstrated to be adequate.
On-going life testing, as described in IEEE Standard 32i-1974, is an acceptable alternative to formal life testing for the purpose of establishing a specific qualified life for the RTBs.
On-going life testing will demonstrate that the qualified life, though not specifically known, is longer (in terms of cycles and time) than the integrated service that will be accumulated through the next refueling interval.
The description of an on-going qualification program should include the following:
1.
Definition of the number of demands per unit of time, to which at RTB must respond, and the basi s for the number (of demands;
I
Pe 2.
Definition of relevant, end-of-life-related failures.
(Note that random failures occurring during the constant hazard rate portion of the "bathtub curve" are not relevant to a life test);
and Definition of the action to be taken upon any failure.
2.2 Periodic Re lacement Pro ram If the qualified life of any component is less than the qualified life of the RTB, then the component should be replaced on an appropriately shorter time schedule.
The criteria developed in support of this item include record keeping for service time and number of cycles for all
'breakers and short-lived devices or components.
I EVALUATION
~. 1 Evaluation of the Licensee Position on Item 4.2.3 The licensee's April 22, 1986, letter states that IC<NEC supported the Westinghouse Owners Group (WOG) reactor trip breaker Life Cycle Testing
- Program, and that the results of that program have been used in the development of their response to Items 4.2.3 and 4.2.4.
The licensee's submittal did not identify the qualified life of the Cook reactor trip breakers.
Neither did it specifically identify the results of the Life Cycle Testing Program by Westinghouse report number.
The WQS report on type DB-50 breakers (the type used at Cook) is WCAP-10852.
WCAP-10852 addresses only cyclic testing on RTB trip attachments.
It does not address life qualification of the RTBs proper.
It does not. even address noncyclic life limiting or performance degrading phenomena (i.e.,
aging) for the trip attachments.
Therefore, this WCAP report does not constitute an acceptable response to the concern of the Generic Letter.
We find that the licensee has not committed to a life testing program.
The breaker 's qual ifi ed 1 ife must be established based on actual testing of the breakers on an acceptable sample size.
On-going life testing would be an acceptable alternative to formal life testing, provided that the licensee program includes the three requirements mentioned under the Evaluation Criteria in this report.
3.2 Evaluation of the Licensee's Position on Item 4.2.4 The licensee has used the results of the WOG Life Cycle Testing Program to establish maintenance intervals for the RTB trip attachments.
The licensee will replace the remainder of the RTB components as periodic preventative maintenance, inspection and surveillance dictate.
We find the licensee position on this item unacceptable.
As discussed in Section
- not, constitute a life test of the RTBs or the components thereof
~
The licensee should identify a replacement program for the breaker and breaker components consi stent with demonstrated 1 ife cycles.
The program should consider data derived from the on-going life testing as well as the design life.
If data from on-going qualification is used, the licensee should consider in-service failures, malfunctions during the periodic maintenance program and indication of degradation or failures from the measurements made for the trending of parameters.
In addition, the licensee should specifically define how the on-going qualification results will be used to establish replacement cycles and times.
4.
CONCLUSIONS Based on a review of the licensee
- response, we find the licensee position on Item 4.2. i and 4.2.4 of Generic Letter 8 -28 to be unacceptable because it does not document the establishment of the qualified life of the RTB and its replaceable components.