ML20034D201
| ML20034D201 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 07/15/1991 |
| From: | Hehl C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Mroczka E NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| NUDOCS 9108150232 | |
| Download: ML20034D201 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION L
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475 ALLENDALE ROAD KING oF PRusSLA. PENNSYLVANIA 194061415 g * * " *,<f'
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Docket Nos. 50-336 File Number RI-91-A-0143 Northeast Nuclear Energy Company ATTN:
Mr. E. J. Mroczka Senior Vice President - Nuclear Engineering and Operations Group P.O. Box 270 I
Hartford, Connecticut 06141-0270 l
Dear Mr. Mroczka:
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The U.S. Nuclear Regulatory Commission recently received information concerning activities at the Millstone Nuclear Power Facility, Unit 2. The details are enclosed for your review and i
followup.
We request that the results of your review and disposition of these matters be submitted to Region I within 30 days of the date of receipt of this letter. We request that your response con:ain no personal privacy, proprietary, or safeguards information so it can be released to the public and placed in the NRC Public Document Room. If necessary, such information shall be contained in a separate attachment which will be withheld from public disclosure.
The affidavit required by 10 CFR 2.790(b) must accompany your response if proprietary information is included. Please refer to file number RI-91-A-0143 when providing your response.
The enclosure to this letter should be controlled and distribution limited to personnel with a "need to know" until your investigation of the concern has been completed and reviewed by NRC Region I. The enclosure to this letter is considered Exempt from Public Disclosure in accordance with Title 10, Code of Federal Regulations, Part 2.790(a). However, a copy of this letter excluding the enclosure will be placed in the NRC Public Document room.
The response requested by this letter and the accompanying enclosure are not subject to the clearance procedures of the Office of Management and Budget as required by the Paperwork Reduction Act of 1980, PL 96-511.
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Your cooperation with us is appreciattd. We will gladly discuss any questions yo concerning this information.
Sincerely, i
Charles W. Hehl, Di.~ector Division of Reactor Projects
Enclosure:
(10 CFR 2.790(a) Information) cc w/o encl:
Public Document Room (PDR)
Local Public Document Room (LPDR)
State of Connecticut bec w/ encl:
W. Raymond, SRI, Millstone Allegation File, RI-91-A-0143 J. Stewan E. Kelly T. Shediosky l
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IggmifTION -
OR LIC DISCLOSURE
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ENCLOSURE Issue 1 ne electrical circuit for radiation monitor RM 8132 (Stack Sample Fan 41B) is improperly wired. Plant documents (Drawings 25203-32022, sht.16 and 25203-39092, sht. 7) and the documents associated with PDCE 2-90-032 fail to adequately describe as built plant conditions. The improper wiring is associated with the sample 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.
Issue 2 A radiation monitor power wiring diagram (Drawing 25203-39092, sht.14B) is marked up with drawing / installation discrepancies, as is a print of radiation monitor connections.
Issue 3 Drawing 25203-31175, sht.102, for wiring T497 between RC-14 and RM 8132 is in error.
Issue 4 An undocumented lifted lead exists in Panel RC14C in the Control Room. [The lead is from Control Room Panel C101 to Control Room Panel RCl4C, 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.] ne isolation feature is not checked during channel functional or calibration tests.
Request Please detamine the validity of the above assertions. If any deficiencies in equipment wiring or station drawings are found, please notify us of the corrective actions you have taken. Please provide us with an atesment of the significance with regard to safety of any identified deficiencies.
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I August 16, 1991 Docket No. 50-336 A09716 PI: Employee Concerns Mr. Charles V. Behl, Director i
Division of Reactor Projects U. S. Nuclear 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 Millstone 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 (Dravings 25203-32022, Sht. 16 and 25203-39092, Sht. 7) and the documents associated with PDCE 2-90-032 fail to adequately describe as built plant conditions.
The improper viring is associated with the sample fan control circuit, and may not have been documented during installation of safety tags to support PDCE 2-90-032,-
when 60 volts vere found to be present at 9 terminals on 2 terminal boards.
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Mr. Charics V. B;hl, Dircet:r
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U. S. Nuclocr Regulatory Commissicn A09716/Page 2 August 16, 1991 Responses 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.
1 Plant Incident Report (PIR)91-061 was issued on June 13, 1991, and identified that renoval of fuses F3 and F4 to remove the power from the RM 8132A flow control circuitry did not remove all power, i.e., 60 volts to ground remained.
Following issuance of PIR 91-061, the condition was researched by repre-sentatives of the Engineering, Generation Test Services, and I&C Depart-ments.
This research concluded that als-viring had occurred in the controls of fan F41B.
The cavse of the ais-viring is not known. The viring was corrected under a separate Automated Vork Order (AVO) and dravings were corrected to reflect the desired connections.
This issue has no significance with regard to safe'ty since the sample fan functioned as designed.
The als-viring came to light during the work necessary to add a new piece of equipment. Fuse renoval did not clear power in all circuits. The iten 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 with drawing / installation discrepancies, as is a print of radiation monitor connections.
Response
The draving number cited, 25203-39092, Sheet 145, is in fact the power flow diagram for Radiation Monitor RM 9327. The actual drawing that should have been referenced is Draving 25203-39092, Sheet 14E.
When 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 vas added under Design Change Request (DCR) M2-P-081-91. The absence of these two details is insignificant in regard to safety.
ISSUE 3:
Drawing 25203-31175, Sht.102, for viring T497 betveen RC-14 and RM 8132 is,
in error.
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Mr. Charles V. Behl, Director U. S. Nuclear Regulatory Commission A09716/Page 3 August 16, 1991
Response
l 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 were actually terminated at terminal points 14 and 15. As a result, DCR M2-P-081-91 was 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 by the design. Had any trouble shooting or design work been needed, the available cable information was sufficient as shovn.
ISSUE 4:
An undocumented lifted lead exists in Panel RCl4C in the Control Room.
(The lead is from Control Room Panel C101 to Control Room Panel RCl4C, and should have been attached to terminal block T6, location 8.
The automatic l
isolation and purge of the normal range ventilation exhaust radiation monitor (RM 8132), by an isolation signal from the extended range monitor (RM S168), is disabled when this lead is lifted). The isolation feature is net checked during channel functional or calibration tests.
Response
The lifted electrical lead was immediately identified by PIR 91-65 on June f
27, 1991, prior to receipt of this issue from the NRC. The 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 vas 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 was 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.
- Bovever, there is no requirement to test this auto purge function (referred to as " isolation feature" in Issue 4 above), and thus this function vas not routinely tested. The testing of this auto purge function has been added to the surveillance procedure for RM 8168.
There is no significance to the lifted Icad with regard to safety, based on the previous reviev. The addition of the testing of this function to the surveillance procedure is consistent with the intent of the original installation.
After our reviev and evaluation, ve find that these issues did not present any indication of a compromise of nuclear safety. As indicated in our responses, several of these issues had previously been identified by l
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Mr. Charles V. B hl, Dircetor U. S. Nuclear Regulatcry Commissicn A09716/Page 4 August 16, 1991 Northeast Utilities' corrective action system.
Ve appreciate the cpportunity to respond and explain the basis of our actions..Please I
contact my staff if there are any further questions on any of these matters.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPAhT FOR:
E. J. Mroczka Senior.Vice President BY:
V. D. Romberg / )
Vice Presiden V cc:
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 E. M. Kelly, Chief Reactor Projects Section 4A i
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