05000387/LER-1985-001, :on 850213,Zone III (Refuel Floor) Isolated on High Radiation Signal & Standby Gas Treatment Sys & Control Room Emergency Outside Air Supply Sys Started.Cause Unknown. Procedures Revised to Initiate Sys

:on 850213,Zone III (Refuel Floor) Isolated on High Radiation Signal & Standby Gas Treatment Sys & Control Room Emergency Outside Air Supply Sys Started.Cause Unknown. Procedures Revised to Initiate Sys

ML20135H904
Person / Time
Site:	Susquehanna
Issue date:	09/19/1985
From:	Crimmins T, Kuczynski L PENNSYLVANIA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION (ADM)
References
LER-85-001, LER-85-1, PLAS-120, NUDOCS 8509240367
Download: ML20135H904 (3)

LER-1985-001, on 850213,Zone III (Refuel Floor) Isolated on High Radiation Signal & Standby Gas Treatment Sys & Control Room Emergency Outside Air Supply Sys Started.Cause Unknown. Procedures Revised to Initiate Sys

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv), System Actuation
3871985001R00 - NRC Website

text

J U S NUCLE AR KEGULATORY COMMISEtON NRCForm308

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P A U' 5 3' 8 ACILITY N AME til DOCKET NUMgER 821 Susauchanna Steam Electric Station - Unit 1 0151010 l 0 l 3lg l 7 1 lOFfg l9 (IYLE 14:

SGTS Start on Refuel Floor High Radiation Signal.

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On February 13, 1985, with the Unit shutdown for its first refueling outage, actions ccrmenced to remove the steam dryer frcm the reactor vessel. 'Ihe maintenance procedure used to move the dryer included steps for the installation of ju:rpers in the refuel floor wall duct trip units. 'Ihis would forestall a Zone III (Refuel Floor) ventilation isolation and conccmitant start of the Standby Gas Treatment System (SGTS) and Control Rocm Emergency Outside Air Supply System (CREASS) under circumstances where it is known that conditions other than airborne radiation would cause the-isolation or systems to start.

(SGIS and CREAOSS are Engineered Safety Features.)

Khen the steam dryer move was ccuplete, the jumpers were rmoved per the maintenance procedure. Within two minutes, Zone III had isolated on a high radiation signal and the SGTS and CPEASS started. The jumpers were replaced and all systm s restored to normal status. Station particulate, iodine and noble gas nonitor data showed no abnormal release rates for the day.

Procedure changes have been inplesmnted to initiate SGTS and CRE0 ASS prior to moving the steam dryer. Mditional actions will be evaluated.

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8509240367 850919 PDR ADOCK 05000387

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W.RC Form 386 89 831

I t%C form 364A U S NUCLEAR REGULATORY COMMISSiOm LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED 098 No U50-0W E R PIR E S 873111$

FACsuTV 4AME m DOCKET muuaER (21 LER NUMeER 133 PAGE(3)

Susquehanna Steam Electric Station

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W,W vEaa Unit 1 o ls to lo jo l 3l 8l 7 8l5 0l0j1 0l1 0l 2 or 0 l2 rm a mne, ass.nm On February 13, 1985, with the Unit shutdown for its first refueling outage, actions comenced to remove the steam dryer frun the reactor vessel. The nuintenance procedure used to move the dryer included steps for the installation of jumpers in the refuel floor wall duct trip units. (The corresponding sensors on Unit 2 rmained operable throughout the event.)

The intent of this action was to forestall a Zone III (Refuel Floor) ventilation isolation and concanitant start of the Standby Gas Treatment Systs (SGTS)

(EIIS Code: BH) and Control Roan Emrgency Outside Air Supply Systen (CRECASS)

(BH) under circumstances where it is known that conditions other than airborne radiation m uld cause the isolation or systems to start.

(The SGIS and CRECASS are Engineered Safety Features.) The strongback used to move the dryer has a sprinkling system installed on it and there is a sprinkling system in the dryer-separator pool to muumize airborne radiation.

Khen the steam dryer move was catplete, the jtrpers were removed per the maintenance procedure. Within two minutes, Zone III had isolated cn a high radiation signal and the SGTS and CREASS started. Operations personnel directed that the jumpers be reinstalled based on the deduction that the steam dryer was acting as a source large enough to affect the sensors in the_ Zone III exhaust duct. CRECASS was shutdown, nornal Zone III ventilation was re-established and SGTS was shutdown. Station particulate, iodine and noble gas monitor data showed no abnormal release rates for the day.

All systen logic functioned properly except that the Reactor Building Recirculation Fans did not start.

(These fans act to recirculate the air within the ventilation zones to reduce radioactivity concentrations by mixing the air before it is exhausted through the Standby Gas Treatment System.)

Investigation into the lack of fan start showed no problens and sinulated conditions resulted in correct logic sequencing including the start of the Fecirculation Fans.

The maintenance procedure used to control transfer of the steam dryer has been revised to initiate the SGTS and CREQASS in a controlled manner.

Additionally, engineering evaluations will be completed to determine the feasibility of shielding the radiation monitors or altering their trip function to assure their actuation on true high airborne radiation indication.

LER's 85-010-00 and 85-020 describe additional occurrences of SGTS and CRECASS actuations due to ' shine'.

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PPaL

.Pcnnsylvania Power & Light Company Two North Ninth Street

• Allentown, PA 18101 e 2151 7705151 September 19, 1985 4

U.S. Nuclear Regulatory Camission Document Control Desk washington, DC 20555 SUSQUEHANNA STF#1 ELECTRIC STATION

. LICENSEE EVENT REPORT 85-001-01 ER 100450 FILE 841-23 PIAS-120 Docket No.

50-337 License No. NPF-14 Attached is Licensee Event Report 85-001-01. This event was determined reportable per 10CFR50.73(a) (2) (iv), in that the Unit experienced an unanticipated start of the Standby Gas Treatment and Control Rocm Dnergency Outside Air Supply Systers, which are Engineered Safety Systens.

= = m e

T.M.

Irmins, Jr.

Superintendent of Plan -Susquehanna IAK/Pj9 cc:

Dr. Thcnus E. Murley Regional Adninistrator, Region I U.S. Nuclear Regulatory Ccamission 631 Park Avenue King of Prussia, PA 19406 Mr. R.H. Jacobs Senior Resident Inspector U.S. Nuclear Regulatory Ccamission P.O. Box 52 Shickshinny, PA 18655 ff l

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