B12192, Forwards Reviews for Listed Isap Topics,Including Topic 1.44, Diesel Generator Reliability, Per 850517 Commitment

Forwards Reviews for Listed Isap Topics,Including Topic 1.44, Diesel Generator Reliability, Per 850517 Commitment

ML20215J406
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	10/16/1986
From:	Opeka J CONNECTICUT YANKEE ATOMIC POWER CO.
To:	Charemagne Grimes Office of Nuclear Reactor Regulation
References
B12192, NUDOCS 8610240427
Download: ML20215J406 (10)

Text

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CONNECTICUT YANKEE ATOMIC POWER COMPANY BERLIN, CONNECTICUT P o BOX 270 HARTFoHD, CONNECTICUT 06141-0270 TELEPHONE 203-665-5000 October 16,1986 Docket No. 50-213 B12192 Office of Nuclear Reactor Regulation Attn: Mr. Christopher I. Grimes, Director Integrated Safety Asse.:sment Project Directorate Division of PWR Licensing - B U.S. Nuclear Regulatory Commission Washington, D.C. 20555

References:

(1) 3. F. Opeka letter to C.1. Grimes, dated May 17, 1985.

(2) H. L. Thompson letter to 3. F. Opeka, dated July 31,1985.

Gentlemen:

Haddam Neck Plant Integrated Safety Assessment Program In Reference (1), Connecticut Yankee Atomic Power Company (CYAPCO) provided a proposed scope for the Integrated Safety Assessment Program (ISAP) review of the Haddam Neck Plant. In Reference (2), the Staff formally issued the results of the ISAP screening review process, establishing the scope of ISAP for Haddam Neck and initiating issue-specific evaluations. Reference (1) also indicated that for each issue or topic included in ISAP, CYAPCO would provide a discussion of the safety objective and an evaluation of the plant design with respect to the issue being addressed to identify specific items to be considered in the integrated assessment. In accordance with this commitment, reviews for the following ISAP topics are attached:

1) ISAP Topic No.1.44 " Diesel Generator Reliability"

2) ISAP Topic No.1.45 "1S1 Update to 1980 Code"

3) ISAP Topic No.1.47 " Reliability Engineering" If you have any questions concerning the attached reviews, please contact us.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY

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3.F.Opekh Senior Vice President i

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Docket No. 50-213 B12192 Haddam Neck ISAP Topic No.1.44 Diesel Generator Reliability October 1986

Haddam Neck ISAP Topic No.1.44 Diesel Generator Reliability I. Introduction In conjunction v>ith Unresolved Safety Issue (USI) A-44, Station Blackout, the NRC Staff has concluded that the reliability of diesel generators is one of the main factors affecting the risk from station ' blackout. Thus, attaining and maintaining high diesel generator reliability is a necessary input to the resolution of USI A-44. Risk from station blackout is such that actions to improve diesel generator reliability may have a significant safety benefit.

II. Review Criteria

1. NUREG/CR-0660 - " Enhancement of On-Site Emergency Diesel Generator Reliability Final Report"

2. Regulatory Guide 1.108 " Periodic Testing of Diesel Generator Units Used as On-Site Electric Power Systems at Nuclear Power Plants"

3. Generic Letter 84-15 " Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability" III. Related Topics / Interfaces ISAP Topic No.1.46 "lST for Diesel Generator Auxiliaries" ISAP Topic No.1.47 " Reliability Engineering" IV. Evaluatior.

The on-site emergency AC power sources at the Haddam Neck Plant consist of two.(2), twenty (20) cylinder General Motors diesel generator units. The air start systems are of the dual air starting motor type. In such a design, the initial engine start signal is received on one bank of starting motors and if an engine start failure is received, the logic automatically shifts to the other set of motors and the start attempt is repeated. A highly reliable starting system is inherent with this redundant design. .

A concern identified in CYAPCO's response to Generic Letter 84-15 for the Haddam Neck Plant is the possibility of rust accumulation fouling engine starting system components and subsequently preventing engine start. To evaluate this concern, the air start systems for each engine were depressurized, breached and thoroughly inspected during the 1986 plant refueling outage. Boroscopic examination of the air receivers and system piping revealed a fine, tightly adherent rust coating on most surfaces.

These findings lessened the concern associated with particulate fouling of  !

system components, however, further evaluations were performed.

Potential corrosion product failure modes were then evaluated. The existing system possesses wye strainers in the main air start header and diaphragm operated main air start valves. These valves are highly reliable and due to their large flow ports and interrial tolerances, are not susceptible to particulate fouling. The only components left unprotected against the effects of rust carryover were the solenoid valves which

control air flow to the air start motors and main air start valves. System modifications have been completed to eliminate this potential failure mode. These include the installation of five (5) micron air filters in the control air system, upstream of each solenoid valve, and the replacement of existing control air tubing with corrosion resistant stainless steel.

Additionally, subsequent correspondence with the Staff (Reference 1) provided:

1. A description of the plant's current program to avoid cold fast start surveillance testing;

2. The currently reliability of each diesel generator based on surveillance test data; and

3. A description of the program for attaining and maintaining a reliabil-ity goal for the diesel generators.

CYAPCO further enhances the reliability of the various onsite emergency power sources through the implementation of a well-documented, compre-hensive preventative maintenance program. The objective of this program is to provide a detailed analysis of equipment condition and allow for the planning of periodic preventative maintenance. ;rhis minimizes the total maintenance costs while maximizing the availability / reliability of critical equipment.

To complement the preventative maintenance program, a performance testing program has been implemented at Haddam Neck to demonstrate emergency power source reliability. Manufacturer recommendations and NRC requirements have been utilized in the formation of the surveillance testing items, which specify testing at least every 31 days. Refueling outages are utilized to perform complete inspection and overhaul of the diesel generator units under the guidance of manufacturer supplied field service representatives.

Overall, these findings indicated that the plant possesses an adequate program for minimizing cold fast start testing and ensuring sufficient engine reliability. This is supported by the reliability statistics, which far exceed the criteria presented in Generic Letter 34-15 and Regulatory Guide 1.108.

V. Conclusion Given the inherent reliability of the subject air start systems and the modifications recently implemented to reduce the likelihood of occurrence of the remaining failure mode, the concerns associated with rust accumula-tion in these systems are now fully resolved. Additionally, surveillance testing, preventative maintenance testing and CYAPCO's ongoing commit-ment toward attaining high diesel generator reliability have shown excel-lent results to date. Therefore, CYAPCO considers these continuing programs adequate and hence considers this ISAP topic closed. Information contained in this ISAP topic will be incorporated into the resolution of USI-A-44, Station Blackout.

VI. Reference

1. W. G. Counsil letter to D. G. Eisenhut, "Information Requested by Generic Letter 34-15," dated February 4,1985.

Docket No. 50-213 B12192 Haddam Neck ISAP Topic No.1.45 ISI Update to 1980 Code October 1986

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Haddam Neck ISAP Topic No.1.45 In-Service Inspection Update to 1980 Code i

. l. Introduction 1

An in-service inspection program is a requirement per 10 CFR 50.55a and

, provides for frequent examination of pumps, valves, welds, supports and other components to detect failure, defects and discontinuities, before they result in larger problems or failures.

II. Review Criteria

1. 10 CFR 50.55a l 2. ASME Code,Section XI "In-Service Inspection of Nuclear Reactor

Coolant Systems"

Ill. Related Topics / Interfaces ISAP Topic No.1.46 "IST for Diesel Generator Auxiliaries" IV. Evaluation .

By References (1) and (2) the Staff issued Haddam Neck License Amendment No. 37 which approved the in-service inspection and testing program submitted for the 'second inspection interval commencing January 1,1978.

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! Since CYAPCO has received the Safety Evaluation Report (Reference 1) covering the initial program submittal, several modifications and additions have been made to 'the program. The in'-service inspection program has 4

been revised to incorporate the requirements of the 1980 Edition of Section XI with addenda up to and including the Winter 1980.

Reference (3) forwarded an updated ISI program to the Staff for approval.

In response to this and other associated relief requests, (See Reference 4),

the updated program was approved and relief was granted on all relief requests except one which pertained to inspection of longitudinal and circumferential piping welds. This relief request approval is contingent upon Staff review of information submitted in Reference 5.

V. Conclusion Further information has been forwarded to the Staff to support relief from code inspection of longitudinal and circumferential piping welds. The updated ISI program will be in effect until January 1,1988. Hence, CYAPCO considers this ISAP topic closed.

P VI. References

1) D. M. Crutchfield letter to W.~ G. Counsil " Approved Technical Specification Changes Related to ISI and Contained Safety Evaluation Report on 151", dated February 26,1981.

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2) D. M. Crutchfield letter to W. G. Counsil "In-service Testing Program For Pumps", dated December 29, 1983.

3) W. G. Counsil letter to D. M. Crutchfield, "In-service Inspection and Testing Program", dated April 9,1984.

4) C.' 3. Grimes letter to 3. F. Opeka," Relief from In-service Inspection Requirements at the Haddam Neck Plant", dated May 12, 1986.

5) 3. F. Opeka letter to C. I. Cr.imes, " Response to Requests for Additional Information on the Relief Request Pertaining to Code

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Inspection of Longitudinal and Circumferential Pipe Welds," dated September 16, 1986.

Docket No. 50-213 B12192 Haddam Neck ISAP Topic No.1.47 Reliability Engineering l

October 1986

Haddam Neck ISAP Topic No.1.47 Reliability Engineering I. Introduction This ISAP topic, " Reliability Engineering", was initially identified in the TMI Action Plan as the final item of task II.C and then in NUREG-0933 as item II.C.4. Reliability Engineering is defined in this topic as such programs that typically determine system and component availabilities, identify high component failure rates, determine basic causes for component failures, identify possible corrective actions, and perform other similar activities. The defined objective of such a program is to contribute to the reduction of risk associated with core melt frequency. It is assumed that without this dedicated effort, the accident frequency over the balance of plant life could increase by a factor of 2. Qualifications used in this issue are reported in NUREG/CR-2800. There is currently no requirement for the licensees to develop and implement such a program.

II. Review Criteria NUREG-0933, Item II.C.4 III. Related Topic / Interfaces None.

IV. Evaluation A Reliability Engineering Branch exists within Northeast Utilities Service Company (NUSCO) with an experienced staff of. engineers and technicians that have developed and implemented several programs' exclusively devoted -

to the reduction or possible elimination of plant reliability and availability problems.

These programs continuously monitor and determine system and component availabilities, monitor on-line equipment performance for failure prognosis, identify high component failure rates, diagnose basic causes for component failures, identify possible corrective actions, and perform other similar activities.

Specific program topics under NUSCO Reliability Engineering include:

A) Availability Improvement Program Hit List (AIP HIT LIST)

Program that identifies and monitors high component forced outage rates and high failure rates of all operating primary and balance of plant (BOP) systems; determines basic causes for component failures and identifies possible corrective actions.

B) Safety System Unavailability Monitoring Program (SSUMP)

Program that identifies and monitors safety system unavailabilities based upon Reference 3. Thus far, a pilot study has been completed.

C) Equipment Analysis This function monitors, identifies, and corrects major rotating equipment problems. Typical activities include vibration monitoring / analyses, balancing, alignment, and failure analyses.

D) Non-Destructive Examination This function monitors equipment integrity to improve plant availability and develops / implements programs required by the NRC.

Additionally, special surveys are performed using infrared thermography or ultrasonic flow devices to identify or diagnose equipment performance problems.

E) Reliability, Availability and Maintainability (RAM) Analyses Program RAM analysis is a systematic approach for evaluating and estimating the impact of a plant change on plant performance as measured by equivalent availability. RAM analyses are used as inputs to the Economic Performance evaluations which are performed as part of the Integrated Safety Assessment Program prioritization activities.

The implementation of these programs is expected to result in an increase in plant reliability, thus resulting in an overall decrease in risk to the public. It should also be noted that these programs complement the Living PRA Progra.n which is in place. See meeting notes regarding June 3,1985 meetings betseen the Staff and Northeast Utilities (NU) on our corporate commitment to a living PRA program.

Based on site surveys conducted by NRC personnel, in conjunction with their respective consultants, it was determined that the Maintenance and Surveillance Program in place at Northeast Utilities plants is adequate.

See References 1 and 2. A recent internal report compared the Haddam Neck Performance Monitoring Program to Reference 4, and concluded that the INPO objectives are met.

V. Conclusions Based on the above, CYAPCO considers these AIP Programs, which repr:.sent an ongoing commitment toward improvement, to be acceptable.

VI. References

1. 3. 3. Shea letter to 3. F. Opeka, " Site Survey of Millstone Unit 1 Maintenance Program and Practices," dated February 13,1986.

2. 3. L. Boccio (Brookhaven National Laboratory) letter to 3. F. Opeka,

" Evaluation of Reliability Technology Applicable to LWR Operational Safety," dated June 17,1986.

3. INPO Good Pr actice OE-903, " Safety System Unavailability Monitoring," dated July 1985.

4. INPO Good Practice, " Plant Performance Monitoring - Development and Implementation" (ITS-414; INPO 86-004), dated February 1986.