A09658, Submits Response to Review of RI-91-A-0137 Issues Concerning Plant Activities

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Submits Response to Review of RI-91-A-0137 Issues Concerning Plant Activities
ML20091E147
Person / Time
Site: Millstone Dominion icon.png
Issue date: 08/16/1991
From: Mroczka E
NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES SERVICE CO.
To: Hehl C
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20091E089 List:
References
A09658, A9658, NUDOCS 9110310096
Download: ML20091E147 (6)
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NORTHEAST UTILITIES o.n...i on<.. . s.wn som s.+n. conn.a.m w -cm . i = w.we

=a w ****o'* w d - MARTFORD. CONNECTICUT D61414270 L L J C,7,((.*E7, ,'g", (203) %k5003 August 16, 1991 Docket No. 50-336 A09655 I Ret Employee Ccncerns Mr. Charles V. Hehl, Diree'or

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Division of Reactor Pr,je E U.S. Nuclear Regulatory E. ission ReFi on I 475 Allendale Road

Dear Mr. Hehl:

H111 stone Nuclear Power Station, Unit No. 2 RI-91-A-0137 Ve have completed our review of the identified issues concerning activities at Hillstont Station. As requested in your transmittal letter, our response does not contain any personal privacy, proprietary, or safeguards information. The caterial contained in this response 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 c,f this response.

ISSUE 1:

On June 3, 1991, an electrician was assigned to disconnect a solenoid valve in vork documented by Vork Order H2-91-03642. In prenration, two pumps vere tagged, fuses in Panel CBS vere pulled and tagged, but power to the solenoid vas not tagged. The tagging was therefore insufficient and a personnel safety hazard existed.

Response

The diaphragm in the operator for 2-BAE-26 had ruptured and was to be replaced. Electriclans vere required to discornect the valve electrically.

In order to accomplish this, the solenoid valve lead vires vere disconnected and the limit switches vere moved out of the way. Fuse F0200C vas tagged pulled which de-onergired the solenoid valve; power to the limit switches was not isolated. In order to move the limit switches, they were unbolted frem their mounting and physically moved aside and tied off.

Moving the limit switches vas a mechanical task which did not require exposing any portion of the electrical components. It was not necessary to isolate the power to the limit switches to safely complete this work.

However, the Job Supervisor judged that the limit switches should have been ,

1 9110310096 911011 .

PDR ADOCK 05000336 P ppR

I Hr. Charics V. B:ble Dirceter 1 - U. S. Nuclcar Regulotcry C:maission A09658/Page 2 August 16, 1991 tagged before they were moved and, in accordance with ACP-0A-2.06 ' Station Tagging," requested Operations to tag the limit switch power supply.

Operations tagged breaker VRil15 and the job was completed.

The tagging was adequate without de-energizing the limit svitches, however, the Job Supervisor alvays has the option to request additional tagging, if he judges it appropriate. It is the Job Supervisor's responsibility to ensure that tagging at the vork site represents a safe condition. This was appropriately done by the Job Supervisor in the conduct of this vork.

Based upon the above, NNECO concludes that no personnel safety harsrd existed.

ISStIE 2:

Or. Hay 31, 1991, during a preventive maintenance task on the "B" EHC motor Vork (P81B), it was discovered that a component tagout was incomplete.

Order M2-90-04610 specified that safety tags be placed at the motor heaters and at the breaker on the MCC vhich supplies power to the heaters.

However, Operations did not tag the heaters c d a personnel safety hazard existed.

Response

The Automated Vork Order (AVO) required the annual motor breaker Preventa-tive Maintenance (PH) to be performed on the EHC pump motor. The motor PH involves an insulation resistance check, and visual inspections of connections at the connection box, cleanliness of the motor, and the condition of the ground leads. The only item that vould involve the motor heater is inspection of the connections at the connection box. The connections are inspected to ensure that they are tight and the insulation is not charred.

there vere no The heate- breater was identified on the work Blueorder tags but vere requested for requirements specified to tag the breaker.

the motor breaker.

The motor heaters are not required to be de-energized and tagged to perform the motor breaker PMs. In this case, the motor breaker PMs vere performed safely using the proper safety equipment without tagging the motor heaters.

All electricians have been trained to check for voltage potential before touching any connections. If a lov voltage circuit, such as a motor heater the Job Supervisor has the or portion of a control circuit, is energized, following options to ensure that the job is done safely:

  • Return the AVO to the Control Room and request Operations to provide additional tagging to isolate the circuits. ,

' Using proper safety equipment, such as lov voltage gloves and safety.

glasses, complete the inspection with the motor heaters energized.

Based upon the above, NNECO concludes that no personnel safety hazard existed. l

)

. Mr. Ch:rles V. B:bl, Dirceter

} U. S. Nuclear Regulatory Commission i

A09658/Page 3 August 16, 1991 ISSUE 3:

On June 3, 1991, during preventive maintenance on the "A" acid feed pump motor in the Condensate Polishing Facility, it was discovered that the component tagout was incorrect and a personnel safety hazard existed. The Vork Ordar M2-90-05941 vas assigned tag clearance 2-1107-91 (see page 1 of the AVO, blocks 1 and 4 of tag clearance sheet SF 210C) however, the blue tag was placed on HCC1B1-3K vhich is the breaker that controls 2CND-P118.

When P11A vas checked, red tags were found on the breaker, recirculation valve, and pump discharge valve using tag clearance 2-1116-91 per Vork Order H2-91-05675.

Responset The opetator creating t'.ie clearance ande an error. He inadvertently identified the breaker for the "B" pump on the tagout. The Job Supervisor detected the error and it was corrected. This second verification of safety tagging prevented a potential personnel safety hazard from being created. The operator has been counseled on this error.

ISSUE 4:

On June 7, 1991, inadequate tagging was identified during Vork Order M2-91-05870. The specific work for which the tagging was incomplete involved adjusting the limit switch for the closed valve position on the "D" Condensate Demineralizer inlet isolation motor operated valve (2-CND-170 or MOV23D). The only electrical tag in place was on the breaker for 2-CND-23D. Operations' records and the P&ID show that additional electrical tags arc required at the outlet valve breaker (2-CND-192 or MOV-37D) as it is interlocked with the inlet valve, at the deminerallrer inlet isolation solenoid bypass valve (2-CND-171 or SOV 221D), and at the liuit switch fuses in Cubicle 1.

Response

The P&ID indicates that there may be an interlock betveen the valves.

Additional investigation is required into the electrical circuits involved.

Corrective action vill be taken when the investigation is complete. This is expected to be e?=pleted by September 15, 1991. A follow-up response vill be provided a. that time.

ISSUE 5:

On June 10, 1991, inadequate tagging and a personnel safety hazard was identified during a motor breaker PM (AVO M2-90-06240) performed on a non-vital chiller (X 196B). It was discovered that the non-vital chiller was energized by the compressor sequencer and the unloader valves.

Response

The AVO required the annual motor breaker PMs to be performed on the 'B' Turbine Room chiller. This chiller is paired with another' chiller and both are controlled through a single sequencer unit which also provides the power for the solenoid valves associated with each chiller. In order to

Mr. Charles V. Behl, Dir0ctor U. S. Nuclear Regulatory Commission A09658/Page 4 August 16, 1991 completely isolate either chiller electrically, both units vould have to be shut down, which is not practical due to operating requirements.

Therefore, the sequencer remained energized and the PMs to the motor and )

breaker vere completed safely without additional tagging. A caution note  :

I has been added to future AVos associated with these units to indicate that multiple pover sources exist for this circuit. Ve do not consider this 1 vork evolution as creating a safety hazard. l 155tm 6:

On June 14, 1991, during work on 4160 volt bus 24A, there was incomplete tagging and extremely dangerous personnel safety condition regarding incomplete tagging and non-conformance with procedures. The work involved removing vorkman grounds from A107, A103, and A104 on the "A" bus and from A504 on the "C" bus. The procedures to install and remove workman grounds were not in the work order. The workman grounds on A304 had been removed with no notation in the AVO and no signature on HP272005. Operations informed Electrical Maintenance that grounds were to remain on A102 as it vould be part of the 24B tagout but no notation of this action was in the AVO. The AVO was signed as complete even thought the grounds were being removed fron A103 and A104; blue tags . existed on the elevator mechanisms breakers -A304A, A102, A103, A104 vere removed from the cubicles with red tags' attached to A304, and no tags on the others and no record existed of workman grounds being removed from-A304. Additional deficiencies includes there. van no copy of MP272006 (metal clad switchgear maintenance) in the work folder as required before the start of work and before department approvals the material accountability sheets were not in the AVO package, the retest was signed off before the grounds vere removed and the bus energized -the DC control power was not tagged during the performance of work on the bust and a red tag on A304 vas removed without proper authorization.

Additionally, a programmatic problem with tagging has been identified for work on the 24A bus. Breaker A304 (tie from 24A to 24C) is physically removed from the cabinet and red tagged. Vorkman grounds are hung on the

! load side and a blue tag is on the elevator mechanism. The RSST side of -

A304 remains hot even with the breaker removed. Therefore, both blue and red tags are being used in the same circuit. If a wrong breaker is installed and closed or a ground cart with the stabs in the wrong position L

is . racked into A304, the hot side of the RSST would be grounded. The l . supposed ground cart scenario occurred at Unit 2 in the past.- Similar but

!- not exactly the same problem exists with breakers A104'and A102 when the breakers are removed and no tags are hung on the breakers.

Response

This issue has been identified to us via internal correspondence from one of our employees. Ve have responded to the employee and continue to.  :

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address the issue with him. AVO M2-90-09797 vas prepared to perform inspections on 4160V bus 24A. Tagging was required and a recommended tagging. list was included with the AVO. The tagging and grounding, including the tagging of the control power and elevator mechanisks, vere reviewed by Operations, the Job Supervisor and Maintenance Supervisor and were determined to be-safe. As in al'. the cases where tagging is required, t

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i Mr. Charles V. Nehl, Dirceter U. S. Nucicar R:gulatory Ccesissien A09658/Page 5 August 16, 1991 3 i

placement of tags,- and in this case grounds, is a prerequisite for i operations -to'authorire commencement of work, which is consistent with

- ACP-QA-2.02C. f The work was completed and the dVO van returned to Operations. Removing  ;

i grounds is a task that Millstone Unit No. 2 Electricians perform under the direction of Operations to assist Operations.in the removal of tags. In order to clear tags, Operations requires that all vork packages associated '

vith- a specific Tag Clearance be in their possession. This procedure is consistent with ACP-QA-2.06A and was followed in the removal of tagging for ,

the 24A bus.- Documents required to support the renoval of grounds and l

associated tagging are:

1. All AV0s on the Tagging Clearance must be-in Operations' possession.
  • AVO M2-90-09797 was the only AVO listed on the Tagging Sheet and it was in the possession of Operations. The AVO was not required to be at the .

job site to remove tags / grounds..

2. Tagging Sheets relating to the Tag Clearance for which tags / grounds are being removed are required to be at the job site with the operator who is removing the tags.- -

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3. If Millstone- Unit No. - 2 Electricians are removing the grounds,
  • Maintenance Procedure MP 272005 for each of *he breakers for which

. grounds are to be removed must be at the job i:Sv.

cordance with ACP-0A-2.02C, the After the work was complete and, in .l procedure. (MP 2720C6) and accountability log associated with the'vork was  !

included in.the work package for historical information.

After the AVO was returned to Operations, the tags associated with breaker A304- were changed, in accordance with ACP-0A-2.06A, to facilitate testing by Generation Test under AVO M2-91-06047. After Generation Test completed ,

the Doble testing 'of the .24A bus,-AVO- M2-91-06047- vas returned to Operations and the ass associated with that work order were cleared. At

-this time, the A304 braaker should have been returned to its cubicle and the ' Red' tag transferred from the breaker to the elevator sechanism.

.The Tagout Sheet clearly indicated that the grounds for breaker A304 had been ~ removed and tags for the p ounds cleared. The Job Supervisor stated l that the cover panelsLto breaker A304 were removed just'to be sure that the >

grounds- vere removed.as indicated on the tag sheets. The other grounds '

associated with the 24A bus were all located such that the associated breaker. vas between the bus and the grounds. Therefore, the 24A bus was isolated but not grounded. Since-Operations held the work orders for the 24A bus and associated breakers, no work vas authorized. If an individual .

violated) the procedures and racked in and closed a breaker into the A304 cubicle,-the 24A bus would become energised, but there would be no short to ground. The procedure for removing grounds is written assuming the- ,

associated bus is energized. Removing grounds from breakers A103 and A104 ,

in accordance with Maintenance Prc.cedure MP 272005 vas safe regardless of i l

L whether the 24A bus was energized or not.

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Mr. Ch rles V. Nehl, Dir cter U. S.: Nuclear Regulatory Commission A09658/Page 6 August 16, 1991 ISSUE 7:

On June 14, 1991, while performing preventive maintenance on SG1 MSIV bypass valve, 2-MS-65A motor operator (Vork Order M2-90-13990) a tagout deficiency related to tag clearance 2-1093-91 vas identified. The clearante authorized only one safety tag (B5207) although power was being fed from ESAS panel RCO2B for an MSI signal and from C01X and C06% for 43X

relay for MSI override. None of these lines vere safety tagged and a personnel safety hazard existed.

Responses AVO M2-90-13990 was prepared to replace damaged seal tite on 2-MS-65A.

Upon inspection it vat. revealed that the seal tite contained no vires.

Tagging the 480V breaker prevented-the valve fros operating, and since there vere rio additional viring involved, the tagging was adequate. l Atter our review and evaluation, we find that these issues did not present

-any indication of a compromise of nuclear tr..~ety. Industrial safety issues identified in these concerns have been adequately addressed by current i plant procedures and safety manuel requirements. Ve continue to strive for a

higher performance in-safety tagging. In the case of-Issue 3, an error was clearly made and identified by the job leader. This is an example of the value in having the person responsible for the safe completion of a job verify safety tagging before the job. is started. Ve appreciate the opportunity to respor.d 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 NUC1. EAR ENERGY COMPANY j FOR: E. J. Mroczka Senior Vice President BY: .

V. D. Romberg Vice President ,

L J. Raymond,' Senior Resident Inspector, Millstone Unit Nos. 1, 2, cc V.

and 3 E. C. Venzinger, Chief, Projects Branch No. 4, Division of Reactor .

Projects E. M. Kelly, Chief, Reactor Projects Section 4A ,

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