ML19262A017
| ML19262A017 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck, Millstone File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 10/19/1979 |
| From: | Counsil W NORTHEAST UTILITIES |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7910260143 | |
| Download: ML19262A017 (9) | |
Text
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NORTHEAST IFI15.FFIES 3
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,*I October 19, 1979 Docket Nos. 50-213 50-336 Darrell G. Eisenhut, Acting Director Division of Operating Reactors Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
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Reference:
(1)
D. G. Eisenhut letter to W. G. Counsil dated June 26, 1979.
Gentlemen:
Haddam Neck Plant Millstone Nuclear Power Station, Unit No. 2
" Occurrence of Inadvertent Reactor Scram and Safety Injection During Monthly Surveillance Tests Of Safeguards Systems at a PWR Facility" In Reference (1), both Northeast Nuclear Energy Company (NNECO) and Connecticut Yankee Atomic Power Company (CYAPCO) were requested to review the events described in Reference (1) and to determine whether existing designs, procedures, and surveillance requirements adequately address multiple equipment failures and the potential for inadvertent reactor scrams.
It was requested that the results of these reviews be submitted in accordance with 10CFR50.54(f) within 30 days from receipt of the Reference (1) letter.
Due to apparent complications with NRC distribution of Reference (1), both NNECO and CYAPCO did not receive the original letter until September 20, 1979, with the requested response date being thirty (30) days from the date of receipt.
Accordingly, CYAPCO hereby submits Attachment (1) in response to the requests of Reference (1) fo: the Haddam Neck Plant; and NNECO hereby submits Attachment (2) in response to the requesto of Reference (1) for Millstone Unit No. 2.
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CYAPCO and NNECO trust this information satisfactorily dispositions the questions armi concerns of Reference (1).
Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY NORTHEAST NUCLEAR ENERGY COMPANY
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',i W. G. Counsil Vice President Attachment 1216 199
STATE OF CONNECTICUT )
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COUNTY OF HARTFORD
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Then persondly appeared before ne W. G. Counsil, who being duly sworn, did state that he is Vice President of Northeast Nuclear Energy Company, a Licensee herein, that he is authorized to execute and file the foregoing information in the name and on behalf of the Licensees herein and that the statements contained in said information are true and correct to the best of hir knowledge and belief.
) ' AY. hk Notary Public My Commisslott Expku March R 2M 1216 200
DOCKET NO. 50-213 ATTACINENT (1)
HADDAM NECK PLANT "0;CURRENCE OF INADVERTENT REACTOR SCRAM AND SAFETY INJECTION DURING MONTHLY SURVEILLANCE TESTS OF SAFEGUARDS SYSTDfS AT A PWR FACILITY" 1216 201 OCTOBER, 1979
guastion (11 You and your plant supervisors should review the events described in Reference (1), to determine whether similar errors have occurred or could occur at your facility and whether the potential exists for a problem associated with occurrences that you have not previously considered.
Response
CYAPC0 has determined that a low probability exists for a similar occurrence of events as described in Reference (1), based on the following:
(1) The Haddam Neck Plant Safety Injection System is not initiated by a differential steamline pressure signal, therefore, it would not be possible for the same sequence of events, as described in Ref erence (1), to occur.
(2) While we have had infrequent failures of some components of the systems in question, we have not had multiple failures as discussed in the subject letter. CYAPCO has taken steps to correct the causes of the previous failures and they are not expected to reoccur.
(3) The auxiliary feedwater pumps and atmospheric relief valves are manual acting.
Question (2)
In addition, it is requested that management policies and procedures be reviewed and strengthened as necessary to assure that multiple equipment failures in safety-related systems will be vigorously pursued and analyzed to identify potential failure modes not previously considered that could lead to a significant reduction in the ability of safety systems to function as required.
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. Response Existing procedures and programs are adcquate to ensure that multiple failures or any other significant failure in any major system will be analyzed. Review of equipment failure is accomplished by a Plant Information Report. This report requires a review by multiple levels of management and the Plant Operations Review Committee. Follow-up action is initiated as required.
In addition, the incident reporting system at CYAPCO is continually reviewed within Northeast Utilities to detect trends in equipment performance and initiate appropriate corrective action.
Question (3)
Finally, you are requested to review your engineered safety system surveillance procedures to determine whether appropriate caations are included and to ensure that plant operators and supervisors are aware of the importance of
.4 voiding challenges to the protective features of your facility.
Response
During the course of approximately twelve (12) years of operation of the Haddam Neck Plant, the majority of procedures have been utilized and reviewed on numerous occasions to ensure that the proper caution statements have been incorporated to prevent unnecessary challenges to the facility protective features. The historical record is perhaps the best indicator of the acceptability of existing surveillance procedures.
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DOCKET No. 50-336 ATTACIMENT (2)
MILLSTONE NUCLEAR POWER STATION, UNIT NO. 2 "0CCURRENCE OF INADVERTENT REACTOR SCRAM AND SAFETf INJECTION DURING MONTHLY SURVEILLANCE TESTS OF SAFEGUARDS SYSTDIS AT A PWR FACILITY" 1216 204 OCTOBER, 1979
Question (1_l You and your plant supervisors should review the events described in Reference (1), to determine whether similar errors have occurred or could occur at your facility and whether the potential exists for a problem associated with occurrences that you have not pr eviously considered.
Response
Northeast Nuclear Energy Company (NNECO) has conducted a review of the events described in Reference (1). To date, no events such as those described have occurred at Millstone Unit No. 2.
Although trips have occurred during routine surveillance testing, none of the trips were attributable to complacency on the part of the person performing the test.
In all cases where trips of this nature occurred, it was fully investigated.
These investigations resulted in system improvements which have essentially eliminated unnecessary challenges to the protection systems.
As previously stated, NNECO has not experienced sequential failures at Millstone Unit No. 2 as described in Reference (1). However, equipment malfunctions coincident with reactor trips have occurred. The investigation of such cases resulted in corrective action to replace defective components and/or improve the system design.
The plant design as described in the Final Safety Analysis Report and the training of the operating staf f and support organizations coupled with detailed procedures result in a low probability for this type of event as demonstrated by the operational history of Millstone Unit No. 2.
Question (2,[
In addition, it is requested that management policies and procedures be raviewed and strengthened as necessary to assure that multiple equipment f i ures in safety-related systems will be vigorously pursued and analyzed t,
identify potential failure modes not previously considered that could lead to a significant reduction in the ability of safety systems to function as required.
Response
Management policies / procedures governing investigation, corrective action, and action to prevent recurrence of equipment failures and malfunctions have been reviewed and evaluated.
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. It was determined, through this review, that existing administrative systems are adequat e and would initiate the actions necessary to assure that multiple equipment failures in safety-related systems are vigorously pursued.
In all cases where failures have occurred that indicated a potential generic problem, prompt concise actions were initiated in order to determine the magnitude as well as the consequences of such a problem.
In addition, the incident reporting system at Northeast Nuclear Energy Company is continually reviewed within Northeast Utilities to detect trends in equipment performance and to take the appropriate corrective action.
Question (3)
Finally, you are requested to review your engineered safety system surveillance procedures to determine whether appropriate cautionc are included and to ensure that plant operators and supervisors are aware of the importance of avoiding challenges to the protective features of your facility.
Response
A review of ' gineered Safety Features (ESF) System surveillance procedures did not reveal any significant deficiencies; however, some minor changes have been made to provide additional assurance that challenges of the (ESF) systems will not occur as a result of surveillance testing.
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