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UNITED STATES
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NUCLEAR REGULATORY COMMISSION 7, @
j WASHINGTON. D. C. 20555 a
9 - ~. s,e AUG 5 1983
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U (ommission,er-GiIinsky MEMORANDUM FOR:
C FROM:
William J. Dircks Executive Director for Operations
SUBJECT:
SALEM ABNORMAL OCCURRENCE (AO) REPORT TO CONGRESS In response to your Memorandum dated July 20, 1983, which provided clarification on your concerns with the subject Abnormal Occurrence Report, I have had my staff conduct a review of the information contained in the report.
While I have fcund the proposed A0 Report to contain accurate information, I would suggest some clarifying changes to the present version. These suggested changes follow specific comments on your concerns.
Soecific Coments (1) The list of "[p]ossible contributors" to the failures of the UV trip attachments at Salem Unit 1, referred to in the A0, is generally consistent with the information provided in the staff's Salem Restart Safety Evaluation Report (SER) (NUREG-0995, p. 3). Additional information contained in the SER (p. 4) included the staff's conclusion, that the predominant cause of failure "was excessive wear accelerated by lack of lubrication and improper maintenance." This conclusion is supported by the results of the staff's independent evaluation of two reactor trip breaker (RTB) UV attachments which were identified by the licensee as those which failed during the February 1983 incidents at Salem Unit 1.
In addition, the staff and its contractor examined a UV attachment which the licensee identified as coming from Salem Unit 2.
Specifically, the staff examined all three of these devices microscopically, and functionally examined two - the device from Unit 2 and the Unit 1A RTB attachment.
It should be noted that Westinghouse reported that their examination of just one of the licensee-identified Unit 1 (RTB 1A) devices was visual only.
In the staff's view, this visual examination could not have provided an adequate basis for a determination of equipment wear.
In addition to conducting its independent evaluation of this equipment,
-the staff and its contractor held a meeting with Westinghouse
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representatives on April 22, 1983. At this meeting, the staff presented a detailed description of its evaluation methods and findings. Following the presentation, the Westinghouse representatives expressed general 3
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4 Commissioner Gilinsky t agreement with the staff's identification of wear on the equipment examined microscopically.
(2) The most recent confirmation of this information is contained in a letter i
from the licensee (April 22,1983) which noted that Mr. Esposito:
1)
" physically worked on one" reactor trip breaker (IA), and 2) " witnessed t
and provided technical direction on the maintenance on 3 other breakers" (reactor trip breaker 1B and motor generator breakers 11-12).
In the same letter, the licensee indicated that both the Unit I reactor trip bypass breakers were maintained by P.S.E.&G. electricians without assistance from Mr. Esposito.
As noted in my April 12, 1983 memorandum to you, Mr. Esposito has stated that he assisted in the maintenance / repair on only one reactor trip breaker and one motor generator set breaker.
(3) This information is consistent with the most recent information forwarded by the licensee and with my April 13, 1983 Memorandum to you on this subject. The licensee has detailed that the following tests were performed following the January 13 to 18,1983 maintenance on the Unit 1 Breakers:
On the Bench In Relay Room No.1 A Trip - UV Trip (48 V Coil) &
- Manual Trip No. 1 8 Trip - UV Trip (48 V Coil) &
- Manual Trip No.1 A Bypass-UV Trip (48 V Coil) &
- Manual Trip No.1 B Bypass-
- Manual Trip Only
- This manual trip was accomplished by holding the Reset Arm, closing the Breaker and then releasing the Reset Arm to trip the breaker.
After Installation in Breaker CubicTes (1) 1 "A" Trip Breaker was tripped during monthly surveillance via the UV trip from the S$PS on
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2-3-83.
(2) 1 "A" Trip and 1 "B" Trip Breakers were tripped from the Reactor Manual Trip Switch which trips both the Shunt and UV Trips on 2-13 and 2-14-83.
(3) 1 "B" Bypass Breaker in the 1 "B" trip position on 2-22-83 was tripped from the Reactor Manual trip Switch which trips the Shunt and Undervoltage Trips.
Comissioner Gilinsky The NRC staff was unable to determine that this testing was not in conformance with the existing Technical Specification requirements at Salem. Following the ATWS events in February 1983, however, the licensee has expanded his surveillance testing requirements and has comited to proposing appropriate Technical Specification changes. The new surveillance program is detailed in NUREG-0995 (pp. 8-10).
In order to clarify the information contained in the A0 Report, I suggest that the following paragraphs be substituted for the first two paragraphs of the "Cause or Causes" section. Additionally, I agree with your concent that the AO (p. 26) reference the restart SER (NUREG-0995). Changes to the "Cause or Causes" section of the previous version are shown annotated for ease of review.
Cause or Causes - On February 25, 1983, approximately two hours af ter the Salem Unit 1 event, the cause of the failure to tri,p was determined by licensee instrumentation technicians to be failure of the VV trip device in both RTBs to function as designed. The same problem had occurred on Feburary 22, 1983, but it was not recognized by the licensee.
As previously discussed, the plant on both occasions was shut dcwn by manual operator action. The-failure-ef-the-WV-trip devises-was-determined-by-the-lieensee-and-the-vender, West 4mghewse,-te-be-dwe-te-exeessive-friet4en-en-a-meehanisal latek-lever-in-the-WV-tF4p-attaehment. Possible contributors to the failure of the UV trip devices are 1) dust and dirt; 2) lack of lubrication; 3) wear; 4) more frequent operation than intended by design; 5)-eerres4en frem-4mpreper-Twbrieatien-4n-January-1983t and 5) r.icking of latch surfaces caused from repeated operation oT the breakers.
IR-additien,-4mpFepeF-maintenamee-and-lubF4 eat 4en-ef-the e4rewit-beeaker-tr4p-bar-mechanism-eewid-have-4nereased-the ferse-mesessaFy-te-aetuate-4tr Based on an independent evaluation of the failed UV trip devices identified by the licensee, the hRC staff concluded that, while the Salem Unit 1 breaker failures occurred as a result of several possible contributors, the predominant cause was excessive wear accelerated by lack of lubrication and improper maintenance.
It appears that no preventive maintenance was conducted on the Salem Unit 1 D8-50 circuit breakers until January 1983.
Additionally, the lubrication recommendations of the Westinghouse 1974 Technical Bulletin and Data Letter were not implemented during the January 1983 maintenance, since personnel performing the maintenance (including a Westinghouse service representative) were not aware of this information. The January maintenance was performed because of a breaker problem which occurred at Salem Unit 2 on January 6, 1983.
In this event, a reactor trip occurred due
Comissioner Gilinsky i to a low-low water level condition in one steam generator and only one RTB operated. The second RTB finally opened 25 minutes later, although the reactor had already tripped from opening of the other RTB. The failure of this RTB was i
concluded by the licensee to be due to dirt and corrosion interfering with proper operation of the UV trip device. As a result of this event maintenance was conducted on all Unit i
1 RTBs, at least one of which involved under-the supervision of the RTB vendor, Westinghouse. The licensee also reported that all RTB reactor trip breakers were sKorily tested after-d maintenance per plant procedures.
s I understand that the Secretary will coordinate these suggested changes with the other Comission offices.
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t sk William J. Dirck's Executive Director for Operations cc: Chairman Palladino Comissioner Roberts Comissioner Asselstine SECY OGC OPE Y
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