05000368/LER-1980-037-01, During Mode 1 Operation, Safety Injection Tanks (SIT) C & D Were Found to Have Boron Concentrations of 1711 Ppm & 1620 Ppm.Probably Caused by Dilution of SIT Makeup Path by Reactor Coolant

During Mode 1 Operation, Safety Injection Tanks (SIT) C & D Were Found to Have Boron Concentrations of 1711 Ppm & 1620 Ppm.Probably Caused by Dilution of SIT Makeup Path by Reactor Coolant

ML19331D651
Person / Time
Site:	Arkansas Nuclear
Issue date:	08/27/1980
From:	Shively C ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19331D649	List:
References
LER-80-037-01X, LER-80-37-1X, NUDOCS 8009030425
Download: ML19331D651 (4)

LER-1980-037, During Mode 1 Operation, Safety Injection Tanks (SIT) C & D Were Found to Have Boron Concentrations of 1711 Ppm & 1620 Ppm.Probably Caused by Dilution of SIT Makeup Path by Reactor Coolant

Event date:
Report date:
3681980037R01 - NRC Website

text

A Ci Revised Report - Previous Report Date 6/17/80 NRC F ORM 366 U. S. NUCLE AR REGULATORY COMMISS60N (7 77)

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74 76 HFPoRT DATE 80 EVENT DESCRIPTION AND PROBA8LE CONSEQUENCES h i o 12 i f Durina Mode 1 operation, Safety In.iection Tanks (SIT) "C"

& "D" were i

i found to have boron concentrations of 1711 ppm and 1620 ppm boron con-1 io i3 i go i. i i centration, which is below the 1731 ppm boron concentration as per i

inisii T.S. 3.5.1.c.

The SIT "A"

& "B" boron concentrations were verified to i

io gi i be at acceptable levels.

Prompt reportable per T.S.6.9.1.8.b due to i

,,,,, i simul taneous out of spec SIT's.

No similar occurrences.

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i,io,i the reactor coolant during extended Shutdown Cooling System operation.

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Reportable Occurrence Report No. 50-368/80-037 2.

Report Date:

3.

' Occurrence Date: 6/3/80 4

Facility: Arkansas Nuclear One - Unit II Russellville, Arkansas 5.

Identification of Occurrence:

Operation of the Emergency Core Cooling System with the Safe +y Injection Tanks (SIT) operability less conservative than tk least conservative aspect of the limiting condition for operation defined in T.S. 3.5.1.c.

6.

Conditions Prior to Occurrence:

Steady-State Power X

Reactor Power _ 2815 Knth 4

Hot Standby Net Output

=925 Kwe Cold Shutdown Percent of Full Power 100

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Refueling Shutdown Load Changes During Routine Power Operation Rcutine Startup Operation i

Routine Shutdown i

Operation Other (specify) i

(

l Description of Occurrence:

l Two SIT's boron concentration simultaneously out of specification for less than one hour.

During routine sampling of the SIT's, it was discovered that SIT "C" and "D" had boron concentrations less than 173:

m boron specified r

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in T.S. 3.5.1.c.

SIT "A" and "B" boron concentrations were verified to be greater than 1731 ppm boron.

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Reportable Occurrence Report No.

8.

Designation of Apparent Cause of Occurrence:

l 3esign Procedure Maniufactu.e Unusual Service Condition Including Environmental Insta11at: ion /

Construction Component Failure (See Failure Data)

Operator Other (specify)

Boration path dilution Based on local sampling tests, a portion of the SIT fill path may be diluted (from the RWT concentration) by reactor coolant during extend.

Shutdown Cooling System operation. With such dilution occurring during the snall makeup operations, the SIT boron concentration is decreased.

9.

Analysis of Occurrence:

The SIT's renuire periodic makeup to maintain T.S. required levels due to volume contraction during unit cooldowns and volume reductions dur ir,g ncrmal operation.

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Reportable Occurrence Report No.

10.

Corrective Action

2 The SIT fill path and fill method is being evaluated to ensure undiluted boration. Boron stratification in the SIT is also being studied.

SIT "C" and "D" were returned to the Tech Spec required boron concentrations utilizing the feed-and-bleed method.

1 11.

Failure Data:

There have been no similar occurrences.

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Failure Data:

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