ML20085L707

AO 50-267/75-4-A:on 750125,tritium Leaked from Secondary Closure of Refueling Region 1.Caused by Normal Presence of Tritium in Pressurizing Gas

ML20085L707
Person / Time
Site:	Fort Saint Vrain
Issue date:	03/14/1975
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20085L708	List: ML20085L707 ML20085L712
References
AO-50-267-75-4A, NUDOCS 8311020361
Download: ML20085L707 (4)

Text

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public Service Company It' CdandD

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i March 14, 1975 Mr. E. Morris Howard, Director Nuclear Regulatory Commission Region IV Office of Inspection & Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012

Dear Mr. Howard:

REF: Facility Operating License No. DPR-34 Docket No. 50-267 Enclosed please find a copy of Abnormal Occurrence Report No. 50-267/75/4-A, submitted per the requirements of the Technical Specifications.

Very truly yours,

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H. Larry Brey Superintendent-Operations Fort St. Vrain Nuclear Generating Station HLB:il cc: Mr. Angelo Ciambusso 1

d, 8311020361 750314 I PDR ADOCK 05000267 [4 {

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Lj nJ February 5, 1975 ABNORMAI. OCCURRENCE

• REPORT DATE:

• Subsequently determined not OCCURRENCE DATE: January 25, 1975 _

to be an Abnormal Occurrence FORT ST VRAIN NUCLEAR CENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO  :

P. O. BOX 361 PLATTEVILLE, COLORADO S0651 REPORT No. 50-267/75/4-A

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Final IDENTIFICATION OF OCCURRENCE: .

When the secondary closure of refueling region #1 was loosened, Health indicating

-Physics personnel detected Tritium leaking from the penetration, a possible breach of the primary closure.

SuchS a breach would be a violation of paragraph 2.1.c of the Technical

. Specifications.

C0!OITICMS 22:CR Steady State Power Routine Shutdown TO OCCURRENCE:

Routine Load Change llot Shutdown Other (specify)

X Cold Shutdown Refueling Shutdown Routine Startup The major parameters at the time of the event were as follows:

Rtr 0 Wth Power Elect. # 0 We N/A psis

- -Secondary Coolant Pressure .

N/A *F Temperature Flow N/A #/hr.

87 psig

., Primary Coolant Pressure Temperature 275 *F Core Inlet 260 ,

• F Core Outlet

' 7 1ov Less than 100,000 _ #/hr.

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.'f- . Page:2 Note: Average core temperature is lower than core inlet because the Prinary Coolant was being heated by passing steam through the"rchcat section of the steam generators.

DESCRIPTION OF OCCURRENCE:

Testing of the operability of Reserve Shutdown Hoppers after modifying the pressurizing supply lines to a " soft seat" type revealed the inability

. to trip the test switch in No. 1 CRD with 35# pressure. It was decided to check the pressurizing line in No. I r.cfueling penetration.

The secondary closure plate on refueling penetration #1 was being removed to examine the Reserve Shutdown pressurizing line. Routine Health Physics coverage established that tritium levels around the secondary seal vent to approximately twice background when the cover hold down bolts were loosened.

This indicated a possible communication of the penetration interspace with the primary coolant (i.e.; a breach of the primary closure).

The secondary cover plate was retightened to stop any outleakage and Tritium -

levels dropped to the previous background level.

The leak, if any, through the primary closure, is less than the allowable for the group, as shown on flow gauges.

APPARENT CAUSE

. DF OCCURRENCE:

1 The helium used to pressurize the intersp' aces on all refueling penetrations is obtained from the high pressure helium storage bottle. This source of

-helium is replenished from the helium storage system. During depressurization of the primary coolant system, helium is bled from the purification system ahead of the hydrogen getter unit to storage. ; This helium would, therefore, contain hydrogen and tritium above background -levels. Therefore, when the -

secondary closure plate was lifted and an increase in tritium levels was noted, the increase above background was due to the normal presence of tritium in the pressurizing gas.

ANALYSIS OF

• OCCURRENCE:

There was no Abnormal Occurrence. Examination of the primary closure seals and pressurization of the interspace revealed no. leakage.

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CORRECTIVE .

ACTION:

Not necessary.

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SIMILIAR REPORTED OCCURRENCES:

None PROGRA>DIATIC IMPACT: .

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Nonc expected due to concurrent maintenance requirements.

CODE IMPACT: i' None i'

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. APPROVED:

- REC 01DfENDED:

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Frank Mathie F/edericE. Swart Superintendent Nuclear Production Superintendent-Maintenance -Public Service Co=pany Fort St. Vrain Nuclear Generating Station of Colorado O

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