A09716, Submits Response to Review of RI-91-A-0143 Issues Concerning Plant Activities
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(203) 665-5000 August 16, 1991 Docket No. 50-336 A09716 RE:
Employee Concerns Mr. Charles V. Behl, Director i
Division of Reactor Projects U. S. Nuclet.r Regulatory Commission Region I 475 Allendale Road King of Prussia, Pennsylvania-19406
Dear Mr. Behl:
Millstone Nuclear Power Station, Unit No. 2 RI-91-A-0143 Ve have completed our review of the identified issues concerning activities at Hillstone Station.
As requested in your transmittal letter, our responses do not contain any personal privacy, proprietary, or safeguards information. _ The material contained in these responses may be released to the public and placed in the NRC Public Document Room at your discretion.
The NRC letter and our response have _ received controlled and limited distribution on a "need to -know" basis during the -preparation of this response.
ISSUE 1:
The electrical circuit for radiation monitor RM 8132 (Stack Sample Fan 41B) is improperly vired.
Plant documents (Drawings 25203-32022, Sht. 16 and
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25203-39092, Sht. 7) and the documents associated with PDCE 2-90-032 fail to_ adequately descriin as built plant conditions.
The improper viring is associated vith the
, ample fan control circuit, and may not have been documented during installation of safety tags to support PDCE 2-90-032, when. 60 volts were found to be present at 9 terminals on 2 terminal boards.
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Mr. Chnrics V. B;hl, Director i
'J. S. Nuclear Regulatory Commission A09716/Page 2 August 16, 1991 Respouse The issue identifies improper viring of the electrical circuit for Radiation Monitor RM 8132's Stack Sample Fan 41B, and notes that this condition may not have been documented during installation of safety tags.
Plant Incident Report (PIR)91-061 vas issued on June 13, 1991, and identified that removal of fuses F3 and F4 to remove the power from the RM B132A flow control circuitry did not remove all power, i.e.,
60 volts to ground remained.
Following issuance of FIR 91-061, the condition was researched by repre-sentatives of the Engineering, Generation-Test Services, and I&C Depart-ments.
This research concluded that mis-viring had occurred in the controls of fan F41B.
The cause of the mis-viring is not knovn. The viring was corrected under a separate Automated Vork Order (AVO) and dravings vere corrected to reflect the desired connections.
This issue has no significance with regard to safety since the sample fan functioned as designed.
The mis-viring came to light during the work necessary to add a new piece of equipment.
Fuse removal did not clear power in all circuits. The item was immediately documented in PIR 91-061 when the tagout revealed that not all power had been removed after the fuses were pulled.
ISSUE 2:
A radiation monitor power viring diagram (Draving 25203-39092, Sht. 14B) is marked up vith drawing / installation discrepancies, as is a print of radiation monitor connections.
Response
The draving number cited, 25203-39092, Sheet 14B, is in fact the pover flov diagram for Radiation Monitor RM 9327. The actual drawing that should have been referenced is Draving 25203-39092, Sheet 14E.
4 Vhen the drawing for RM 8132A/B vas referenced (39092, Sheet 14E), it was found not to show the existing timer relays, used for recording run times, and was missing a spare contact termination arrangement.
This information was.added under Design Change Request (DCR) H2-P-081-91.
The absence of these two details is insignificant in regard to safety.
ISSUE 3:
4 Draving 25203-31175, Sht. 102, for viring T497 between RC-14 and RM 8132 is.
in error.
'. Mr.. Charles V.'Behl, Directcr U. S. Nucle:r R:gulctory C:maission
. A09716/Page 3 August 16, 1991~
Responses Draving.25203-31175, Sheet 102 shoved that-the terminations of two cables being - joined together vere on terminal points 7 and 8.
Field inspection revealed that_the two cables vere actually terminated at terminal points 14 and 15. As a result, DCR M2-P-081-91-vas issued to correct the drawing and
~show the correct termination-location. This issue has no significance in regard to-safety. All cables were found to be joined together-as required b'y - the design. Bad any trouble shooting or design vork been needed, the available cable information was sufficient as shovn.
ISSUE 4
- An endocumented lifted lead exists in Panel RC14C in the Control Room.
(The lead is from Control Room Panel C101 to Control Room Panel RC14C, and should :have been attached to terminal block T6, location 8.
The automatic isolation :and purge of the normal range ventilation exhaust radiation monitor- (RM 8132), by an isolation signal from the extended range monitor (RM 8168), is disabled when this lead is lifted). The isolation feature is not checked during channel functional or calibration tests.
Response
- The lifted electrical lead was immediately identified by PIR 91-65 on June 27, 1991, priorito receipt of this issue from the NRC. Tia lifted lead, when-landed, vould permit a high radiation alarm relay from the high range.
Radiation Monitor RM 8168 to open the _ air-purge supply valve, 2-HV-456.
This. valve is on the-inlet to RE 8132B, and when opened allows air to purge the inlet of the detector. This feature was added during the design and installation of RM 8168, as a desirable protective function to prevent the monitor from becoming contaminated by high level activity leaving the stack. The auto _ purge function vas tested satisfactorily after its initial installation, but it cannot be determined when'the lead was lifted.
The absence of the lead would have prevented the auto purge of RM 8132B's detector.
- However, there.is no requirement to test this auto purge function _(referred to as " isolation feature" in Issue 4 above), and thus this - function was not routinely. tested. _The testing of this auto purge function has been added to the surveillance procedure for RN 8168.
-There.is no significance to the lifted lead with regard to safety, based on the previous review. The addition of the testing of this function _to'the aurveillance procedure is consistent with the intent of the original installation.
After our reviev and evaluation, ve find that these issues did not present compromise of nuclear safety. As indicated in our any indication of a responses, several of these issues had previously been identified by I
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Mr. Charles V. R;hl, Director U. S. Nuclear Regulatory Commission A09716/Page 4
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~ August 16,jl971 Northeast -Utilities' corrective action system.
Ve appreciate the opportunity to respond and ' explain' the basis of our actions.
Please-contact my staff if there are any further questions on any of these matters.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY FOR:
E. J..Mroczka Senior Vice President BY -
V.D.Romberg[j Vice Presidenr cci V.
J. Raymond, Senior Resident ' Inspector, Millstone Unit Nos,-
1, 2, and 3 E.- C. Venzinger, Chief, Projects Branch No.
4, Division of Reactor Projects-l.
E. M. Kelly, Chief, Reactor Projects Section 4A l
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