ML20141P124

Incident Rept DPC-86-1:on 860104,seal Inject Supply Line Separated at Swagelock Fitting,Spraying Water & Resulting in Reactor Shutdown.Cause Unknown.Mechanical Seal on CRD 2 Reworked

ML20141P124
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	03/06/1986
From:	Parkyn J, Taylor J DAIRYLAND POWER COOPERATIVE
To:	NRC OFFICE OF ADMINISTRATION (ADM)
References
DPC-86-1, LAC-11452, NUDOCS 8603190035
Download: ML20141P124 (4)

Text

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's D DA/RYLAND h k COOPERAT/VE LA CROSSE BOILING WATER REACTOR (LACBWR)

• P.O. BOX 275 GENOA, WISCONSIN 54632 + (608) 689-2331 March 6,1986 In reply, please refer to LAC 11452 DOCKET NO. 50-409 Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

DAIRYLAND POWER COOPERATIVE LA CROSSE BOILING WATER REACTOR (LACBWR)

PROVISIONAL OPERATING LICENSE NO. DPR-45 INFORMATIONAL INTERNAL INCIDENT REPORT l

Gentlemen:

Enclosed is an information copy of LACBWR Internal Incident Report No. 86-1. The circumstances of the incident do not meet the criteria for a Licensee Event. The Resident Inspector, however, requested that we submit a copy of our Internal Incident Report for information only. Therefore, this report is being submitted. It is not a Licensee Event Report.

If there are any questions, please contact us.

Sincerely, DAIRYLAND POWER COOPERATIVE

///VS

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8o03190035 DR 860306 .

James W. Tayh r' ADDCK 05000409 General Manager PDR i

JWT/LSG/ lam

! Attachment cc: J. G. Keppler, NRC Reg. III NRC Resident Inspector b l N j J. Stung pc2-6.7

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DA!RYLAND POWER COOPEPATIVE CORPORATE HEADOUARTERS.P O BOX 817 LA CROSSE WISCONSIN 54601 *(608J 788 4000

LACBWR INCIDENT REPORT 1.0 Report No. DPC-86-1 2.0 Date and Time of Incident 01/04/86 at 2059 3.0 Incident Subject Upper Control Rod Drive No. 2/ Seal Inject Leak Resulting in Reactor Shutdown 4.0 Component that Failed Swagelock Fitting Seal Inject Supply to #2 CRD and Upper Control Rod Drive (UCRD) #2 Mechanical Seal 5.0 Similar Occurrences None 6.0 Operating Conditions at Time of Incident Condition I Reactor Power 94% Generator Output 49 MWe other:

7.0 Description of Incident Prior shifts had experienced sharp increase in #2 CRD effluent temperature and excessive seal water leakage from its malfunction leakoff. The swing shift crew was able to reduce temperature to as low as 210o F, but leakage would not stop. Reducing temperature involved cycling seal inject (SI) supply valves, adjusting other rod temperatures, increasing SI flow to rods and tapping on SI supply line to #2 CRD which redistributed crud in the line and affected seal water flow. It was while tapping on the supply line that the line separated at a Swagelock fitting, spraying seal inject water.

8.0 Immediate Evaluation, Corrective Action and Results The Shift Supervisor called the Control Room and told them to commence reactor shutdown using all rod insert. He called the Health Physics (HP) Technician and had the technician bring a wetsuit to sub-basement. He put wetsuit on and was able to shut seal inject supply valve to #2 CRD. The leak stopped immediately. Reactor power was held at 30 percent. The auxiliary operator isolated #2 CRD j

j effluent valve. A mechanic was called in. He repaired the Swagelock fitting. No primary water leaked from the separated line. There is a check valve in each seal inject supply line.

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e Seal inject supply was cut back into #2 CRD slowly over a matter of hours to limit the cooldown effects on the CRD upper flange. The leakage from CRD #2 was monitored closely. No flange leak developed.

The reactor engineer was called regarding control rod programming. The rods had been inserted to approximately 40 inches (18 and 12/16 inches

- Rod 1) with the all rod insert pushbotton, except for Rod 2, which was electrically disabled. Rod 2 had been energized and driven to approximately 40 inches following the all rod insert. He recommended that power be reduced to less than 25 percent for the return to rod programming. He authorized a withdrawal rate of greater than one inch per hour per procedure. Conttol rods we re moved within procedure limitations to start re establishing rod programming. On January 5, '

the Reactor Engineer further authorized a withdrawal rate for the return to rod programming of I 8 inches /haur, as long as power remained below 25 percent.

On January 5. CRD 2's effluent temperature and leakage increased. A trough was rigged to divert some water from splashing other control rod drives. The seal wccer leak rate was approximately 1.2 gpm on the morning of January 5. It was decided to proceed with reactor shutdown.

At 1050, the shutdown commenced from 23 percent power. The plant was off the line at 1305, with all control rods in at 1309. The activity of a sample of the water leakage demonstrated that it was essentially seal inject water.

9.0 Abnormal System or Fouipment Response None Is the incident radiological in nature? YES X NO 10.0 {E] Supt. or Desig. Alternate Notified Paul C. Moon 01/04/86

_ S/S Date

[_] NRC Report Not Required

_ S/S Date

[_] Requires Ops. Engr. Determination

_ S/S Date

[X] NRC Report Not Required L.S. Goodnan 01/05/86 except for >152/ hour Operations Eng. Date spectat report

((]NRCReportRequired: 1 Hour 4 Hours 30 Days Part 21

((]l-or4-HourNotif.Made: Date Time Notification Made By

[E] Public Service Date 01/06/86 Poon Commission Report: Time 0850 Individual Contacted pc2-6.6

9 11.0 Perlmanent Corrective Action An analysis was perforised which verified that power distribution limits were not exceeded following the all rod insertion.

The mechanical seal on CRD #2 was reworked.

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J..D./ Parkyn, LA6BWR Superintendent Reviewed by ORC 2 5 16 Date JDP:LSG: lam DISTRIBUTION: SRC ORC (Ltd.) NRC Resident Inspector INPO File R5g 1

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