ML20040C358
| ML20040C358 | |
| Person / Time | |
|---|---|
| Issue date: | 01/26/1982 |
| From: | Stello V NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Eisenhut D, Jordan E, Mausshardt D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE), NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS), Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20040B934 | List: |
| References | |
| NUDOCS 8201270565 | |
| Download: ML20040C358 (4) | |
Text
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JAN 26,
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HEMDRANDIR1 FOR: Darrell G. Eisenhut, NRR m
Edward L. Jordan, IE Donald B. Mausshardt, HMSS Robert M. Bernero, RES Clemens J. Heltemes, Jr., AE00 Joseph Scinto, ELD FROM:
Victor Stello, Jr., Chairman Comittee to Review Generic Requirements
SUBJECT:
BACKGROUND INFORMATI0?! ON " ELECTRICAL TER?tINAL BLOCKS" Enclosed is the Sumary Sheet and additional background infomation on the " Electrical Terminal Block" issue scheduled for the sixth CRGR neeting on January 27, 1982.
%TgTnc1 Sicned bi gictoz t.e.Wa,
s Victor Stello, Jr., Chaiman Comittee to Review Generic Requirements
Enclosure:
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4 ADDRESSED BY CRGR IDENTIFICATION:
Research Information Letter (RIL) 123,
" Electrical Teminal Blocks" DESCRIPTION:
RES, based on a contractor's recommendations i'n NUREG/CR-1682 " Electrical Insulators in a Reactor Accident Environment, issued RIL 123 which contained the following recommendations concerning electrical terminal blocks in circuits important to safety within the reactor containment:
o Verification that all teminal blocks are enclosed in an appropriate protective enclosure.
o Cleaning terminal blocks after construction and possibly periodically thereafter.
o Formulation of maintenance procedures and guide-lines for keeping terminal blocks clean, o For new plants, eliminate, hermetically seal or move terminal blocks outside containment.
. OBJECTIVE:
RES wants recommendations in RIL 12') brought to the attention of licensees through the issuance of a specific IE Information Notice on this subject.
BACKGROUND:
In response to an IE bulletin requesting a review of "
electrical equipment important to safety required
'to operate durins a LOCA, approximately 20% of the terminal blocks in TMI-2 containment which had not been adequately qualified for LOCA operation were replaced with qualified pemanent splices. After the THI-2 accident RES management posed the question of whether or not the accident could have been worse if -
the terminal blocks had not been replaced. RES initiated a project to assess the adequacy of teminal blocks to function during loss of coolant and steam line break accidents.
BASIS:
RES initiated project.
SCHEDULE:
IE has drafted an IE Information Notice, with input from RES, which is being circulated to NRR for coment.
Since this Notice is intended for information only, implementation will not be required by the licensee.
CONTACT:
RES-Goller/Wenzinger ISSUES:
The following concerns have been raised:
1.
Whether an IE Infomation Notice should be issued l
that addresses the recommendations made in the l
report and their bases.
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2.
Whether the contractor' study is technically sound. A question has been raised as to whether the test results support the final recommendations in the report. There is also concern that the contractor developed probability model, which could be used in future equipment qualification work, may not be valid.
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3.
Although the main issue is the cleanliness of teminal blocks, no effort app ars to have been made to determine appropriate cleaning techniques for the licensee to implement. The technique discussed in RIL 123 as effective in the laboratory is later caveated to possibly cause deleterious surface contamination with some types of teminal blocks.
VIEWPOINTS:
RES - Feels it is essential that an IE Infomation Notice be issued on terminal blocks that includes the recommendations made in the report and their bases to insure that licensees and other readers can draw the proper conclusions.
IE - Believes that the issue of cleaning terminal blocks is already being addressed in Appendix B to 10 CFR Part 50 and would prefer to include the results of the contractor testing in one of the periodic composite information notices to all licensees.
DEDR0GR STAFF -
1.
Concerned about issuing an IE Infomation Notice (implying NRC endorcement) that is based on a report whose technical soundness is questioned.
2.
Question the appropriateness of testing three different teminal blocks and then proposing that the' results apply across the board without a more thorough review. The following conflicting statements were excerpted from RIL 123 (emphasis added)
"B.ased upon a cursory review of other terminal blocks used in nuclear power plants, the conclusions reached as a result of this research and the recommendations made in this RIL are pertinent to all_ terminal blocks that may be exposed to LOCA or steam line break conditions. (page 1)
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..., the results of this research should generally apply to all terminal blocks of similar geometry and using similar phenolic insulating materials".
(page4)
"No attempt was made to test all generic -
terminal blocks, and the failure rate may vary significantly for different designs."
(page 7)
REFERENCES / ATTACHMENTS:
Reference - NUREG/CR-1682 " Electrical Insulators in a Reactor Accident Environment" Attachment to Summary - RIL-123 " Electrical Tenninal Blocks"
- Draft Information Notice on Terminal Blocks
- Memo R. Minoque to J. Austin dated 1/5/82 Attachments previously sent to CP.GR December 17, 1981 with cover letter from DED Stello to Office Directors of NRR, IE and RES -
Memo W. Dircks to Commissioner Ahearne dtd 12/9/81 Memo R. Minoque to Comissioner Ahearne thru W. Dircks dtd 12/9/81.
RECOMMENDATIONS / COMMENTS TO CRGR:
1.
Consider withholding industry notification until the question surrounding the technical soundness of report is resolved.
Perhaps an unbiased technical review may be appropriate.
2.
Consider the importance of identifying the extent to which the three tenninal blocks tested are representative of those used throughout industry.
3.
Recommend that cleaning technique not be identified when the results of its application in the plant have not been evaluated.
- Attachment previously sent to CRGR December 30, 1981 with cover letter from DED Stello to R. Miroque Memo J. Austin to V. Stello dated 12/28/81
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