ML20154B476
| ML20154B476 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 09/02/1988 |
| From: | Hunsader S COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-1002 5076K, NUDOCS 8809140024 | |
| Download: ML20154B476 (2) | |
Text
/7 Commonwealth Edloon
_ /] One Rrst Natx: mal Plaza. Chicago, Ithnois
(
Address Reply t1 Post Offce Box 7C
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's-Q ChW Itknois 60690 07e?
September 2, 1988 Mr. T. E. Murley Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC. 20555 Attn:
Document Control Desk
Subject:
Braidwood Units 1 and 2 Limitorque Operator Lubrication NRC_Doch t._lio. 50-456
Reference:
(a)
NUREG-1002, Safety Evaluation Report. Supplement #6, dated May, 1988 (b)
August 26, 1988 S.C. Hunsader letter to T.E. Murley
Dear Mr. Murley:
I Section 3.9.1 of Reference (a) review of Commonwealth Edison's (Edison)provided the NRC staff's submittals that addressed mixed grease within Limitorque valve operators.
On page 3 1, the NRC acknowledged that Edison had identified 68 operators in both Units 1 and 2, that had grease mixtures greater than 5% SUN EP 50 mixed with Exxon Nebula EP0/EPl.
(At this time, these operators have had the grease removed and replaced with Exxon Nebula EPl.)
On page 3-3, the NRC staff provided the following comment:
"There is limited data on the affects of radiation ex ocure on mixed greases.
Niagara Mohawk environmental testing of a m xture of calcium and lithium lead based greases resulted in no unacceptable degradation due to radiation.
Although the test data is not directl grease bases, y applicable to the Braidwood grease mixture (cimilar but unidentified trade names and composition), it does provide an indication of the radiation resistance of a mixture of similar chemical constituents."
In response to this comment and to verify that the as-found grease mixtures at Braidwood Station would have performed their intended function, mixtures of SUN EP50 and Exxon Nebula EP0/EPl greater than 5% were radiation tested.
The results of that testing were provided to the NRC staff in reference (b).
The samples of Exxon Nebula EP0/EP1 mixed with Sun EP50 had maintained a g9240024 800902
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consistency whereby the lubricating capability had not been l
reduced.
Under a radiation exposure condition, it 'ias verifled that the grease will perform its intended lubricating function.
1 As indicated in reference (b), valve IRC 8001 A is a main i
l loop isolation valve that is power locked out during all operational l
2 modes.
Power is restored only during shutdown to expedite NSSS f
maintenance.
This valve serves no safety function beyond maintaining the Reactor Coolant System boundary, thus operability and E.Q. qualification are not issues.
The grease in this valve has i
not yet been changed out.
Appropriate documents are being revised
{
to indicate this change in EQ status, j
j In light of discussions held during the Enforcement 1
Conference held at RIII on August 17, 1988, this information has l
been provided to the NRC staff to be reviewed for the purpose of i
q assessing safety significance.
The results of such a review will be J
relevant to any final enforcement actions taken.
I Please address any questions concerning this matter to this I
office.
Very truly yours,
,/ C. f G k S. C. Hunsader
(
Nuclear '.icensing Administrator
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/kij cc:
S. Sands-NRR W. Forney-RIII I
l Braidwood Resident Inspector t
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