05000397/LER-1991-005, :on 910402,determined That Oxygen Concentration in Wetwell Not Being Verified Once Per Seven Days,Per TS Due to Inadequate Procedures.Contractor Hired to Review TS SRs Against Plant Procedures (Pp) & Pp 7.0.0 Revised

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:on 910402,determined That Oxygen Concentration in Wetwell Not Being Verified Once Per Seven Days,Per TS Due to Inadequate Procedures.Contractor Hired to Review TS SRs Against Plant Procedures (Pp) & Pp 7.0.0 Revised
ML17290A166
Person / Time
Site: Columbia Energy Northwest icon.png
Issue date: 04/01/1993
From: Fies C
WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17290A165 List:
References
LER-91-005, LER-91-5, NUDOCS 9304050198
Download: ML17290A166 (6)
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LER-1991-005, on 910402,determined That Oxygen Concentration in Wetwell Not Being Verified Once Per Seven Days,Per TS Due to Inadequate Procedures.Contractor Hired to Review TS SRs Against Plant Procedures (Pp) & Pp 7.0.0 Revised
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(i)
10 CFR 50.73(a)(2)(ii)
10 CFR 50.73(a)(2)(iii)
10 CFR 50.73(a)(2)(v), Loss of Safety Function
10 CFR 50.73(a)(2)(vii), Common Cause Inoperability
10 CFR 50.73(a)(2)(viii)(A)
10 CFR 50.73(a)(2)(viii)(B)
10 CFR 50.73(a)(2)(x)
10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3971991005R00 - NRC Website
v • d • e

text

ACILITY NAHE (1)

LICENSEE EVE%REPORT (LER)

Washin ton Nuclear Plant

- Unit 2 DOCKET NUHBER (

)

PAGE (3) 0 5

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I DF ITLE (4)

OXYGEN CONCENTRATION IN SUPPRESSION CHAMBER WAS NOT VERIFIED PER TECHNICALSPECIFICATION REQUIREMENTS EVENT DATE (5)

LER NUMBER ( 6)

REPORT DATE (7)

OTHER FACILITIES INVOLVED (B)

MONTH 0

4 DAY 0

2 YEAR YEAR 9

I 9

I SEQUENTIAL

,NUHBER 0

0 5

EVI5 ION NUHBER 0

1 MONTH DAY YEAR 0

4 0

1 9

3 FACILITY NAHES CKET 0 0 0 000 NUMBERS(S)

P ERAT ING ODE (9)

HIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5:

(Check one or more of the following) (11)

I OWER LEVEL (10) 20.402(b) 0.405(a)(1)(i) 20.405(a)(1)(ii) 20.405(a)(l)(iii) 20.405(a)(1)(iv) 20.405(a)(1)(v) 20.405(C) 50.36(c)(1) 50.36(c)(2)

X 50.73(a)(2)(i) 50.73(a)(2)(ii) 50.73(a)(2)(iii) 0.73(a)(2)(iv) 50.73(a)(2)(v) 50.73(a)(2)(vii) 50.73(a)(2)(viii)(A) 50.73(a)(2)(viii)(B) 50.73(a)(2)(x) 77.71(b) 73.73(c)

THER (Specify in Abstract elow and in Text, NRC orm 366A)

AHE LICENSEE CONTACT FOR THIS LER (12)

C. L. Fies, Licensing Engineer TELEPHONE NUMBER REA CODE 5

0 9

7 7

4 1

4 7

COHPLETE ONE LINE FOR EACH COHPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE

SYSTEH COMPONENT MANUFACTURER EPORTABLE 0 NPRDS

CAUSE

SYSTEH COHPONENT MANUFACTURER REPORTABLE TO NPRDS SUPPLEHENTAL REPORT EXPECTED (14)

YES (If yes, cerpiete EXPECTED SUBHISSION DATE)

NO 1RACI I1 OI EXPECTED SUBMISSION HONTN DAY YEAR ATE (15)

On April 2, 1991, a Plant Operations Engineer determined the oxygen concentration in the wetwell was not being verified to be within limits once per seven (7) days as required by the WNP-2 Plant Technical Specifications.

This condition was determined as a result of an evaluation of a previous event in which the technical specification limitfor oxygen concentration in the wetwell was exceeded.

The immediate corrective action was to implement a procedure deviation to include the technical specification oxygen verification requirements for the wetwell.

The root causes for failing to routinely monitor the oxygen concentration in the wetwell per the Technical Specification surveillance requirements include: 1) the procedures were less than adequate because they did not require wetwell oxygen concentration be verified to be within limits, and 2) management direction was less than adequate to ensure that all technical specification surveillance requirements are included within the Plant procedures.

A contributing cause was a design deficiency in the containment monitoring system (CMS-CP-1301 and CMS-CP-1401).

9304050}98 930401 PDR ADOCK 05000397 8

PDR

LICENSEE EVENT REPORTER)

TEXl CONTINUATION ACILITY NAME (1)

Washington Nuclear Plant

- Unit 2 DOCKET NUMBER (2) 0 5

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ev.

No.

i 05 Ol LER NUMBER (8) ear umber PAGE (3) 2 F

6 1TLE (4)

OXYGEN CONCENTRATION IN SUPPRESSION CHAMBER WAS NOT VERIFIED PER TECHNICAL SPECIFICATION REQUIREMENTS

~Abstrnc (Continued)

Corrective actions include performing a complete review of technical specification surveillance requirements against Plant procedures, require logging of Reactor Building to wetwell vacuum breaker actuations and subsequent monitoring of wetwell oxygen concentration.

The safety significance of this event is minimal because the probability of occurrence of a design basis accident requiring low wetwell oxygen concentration to maintain containment integrity coincident with wetwell oxygen concentration high enough to actually challenge containment integrity is considered low.

Plant nditi ns Power Level - 100%

Plant Mode - 1 (Power Operation) vent De cri ion On April 2, 1991, a Plant Operations Engineer determined the oxygen concentration in the Primary Containment wetwell was not being verified to be within limits once per seven (7) days as required by the WNP-2 Technical Specifications.

This condition was determined as a result of an evaluation of a previous event in which the technical specification limitfor oxygen concentration in the wetwell was exceeded.

On March 30, 1991, at approximately 1215, with the Containment Monitor System normally lined up to monitor the Drywell, a Shift Manager (a licensed Senior Reactor Operator) temporarily realigned the system to monitor the wetwell, The recorder (CMS-02R-1) indicated, approximately 3.9 percent oxygen concentration in the wetwell. This exceeded the allowable limitof 3.5 percent in Technical Specification Section 3.6.6.2.

The oxygen concentration in the drywell was within the limits at approximately, 2.5 percent.

At 1225 hours0.0142 days <br />0.34 hours <br />0.00203 weeks <br />4.661125e-4 months <br /> on March 30, 1991, the Technical Specification Action Statement for Drywell and Suppression Chamber Oxygen Concentration, Section 3.6.6.2, was entered.

At 1411 hours0.0163 days <br />0.392 hours <br />0.00233 weeks <br />5.368855e-4 months <br />, PPM 7.4.11.2.1.2.1, Primary Containment Purge Sampling and Analysis, was initiated in preparation for purging primary containment to reduce the oxygen concentration in the wetwell. At 1525 hours0.0177 days <br />0.424 hours <br />0.00252 weeks <br />5.802625e-4 months <br />, PPM 2.3.1, Primary Containment Venting,- Purging and Inerting, was initiated to purge primary containment.

At 1617 hours0.0187 days <br />0.449 hours <br />0.00267 weeks <br />6.152685e-4 months <br />, the primary containment purge was completed.

At 1634 hours0.0189 days <br />0.454 hours <br />0.0027 weeks <br />6.21737e-4 months <br />, oxygen concentration in the wetwell was 0.6 percent and 2.5 percent in the drywell as indicated by CMS-02R-1 and CMS-02R-2 recorders.

With the oxygen concentration in primary containment less than the allowable 3.5 percent, the Technical Specification Action Statement 3.6.6.2 was exited.-

LICENSEE EVENT REPORTER)

TEXT CONTINUATION AC1LITY HAHE (1)

Washington Nuclear Plant

- Unit 2 DOCKET NUHBER (2) 0 5

0 0

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9 7

LER HUHBER (8) ear umber ev.

Ho.

1 05 1

ITLE (4)

OXYGEN CONCENTRATION IN SUPPRESSION CHAMBER WAS NOT VERIFIED PER TECHNICAL SPEC IFICATION REQUIREMENTS AGE (3) 3 F

6 r

Upon review of the March 30, 1991, event, a Plant Operations Engineer realized the Plant procedure for Shift and Daily Instrument Checks, PPM 7.0.0, contained no requirement to routinely monitor the oxygen concentration in the wetwell. The Technical Specification Surveillance Requirement Section 4.6.6.2 states that "The oxygen concentration in the drywell and suppression chamber shall be verified to be within the limitwithin 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after THERMALPOWER is greater that 15 percent of RATED THERMALPOWER and at least once per seven (7) days thereafter."

Therefore, it was determined the technical specification surveillance requirement for oxygen monitoring of the wetwell was not being satisfied.

On April2, 1991, PPM 7.0.0 was deviated to include a requirement to monitor and verify wetwell oxygen concentration is within acceptable limits.

Immediate C rrective Ac i ns The immediate corrective action was to implement changes to the shift and daily instrument surveillance procedure, PPM 7.0.0, to require daily verification that oxygen concentration in the wetwell is within acceptable limits.

Further Eval i n nd rrec ive A i n A. P~hE This event is reportable per 10CFR 50.73(a)(2)(i)(B) as a condition prohibited by the Plant's Technical Specifications.

Plant procedures did not require verifying the wetwell oxygen concentration is less than 3.5 percent at least once per seven (7) days.

As a result, the oxygen concentration in*the wetwell'as not being routinely monitored and recorded as required by Technical Specification Section 4.6.6.2.

2. The Containment Monitoring System was designed to automatically sample the drywell and the wetwell. This feature has not been utilized at WNP-2 since the system was installed because of excessive maintenanc'e needs to maintain this automatic feature.

There were no other structures, components, or systems inoperable prior to the event which contributed to the event.

3. The root causes of failing to routinely monitor the oxygen concentration in the wetwell per the Technical Specification surveillance requirements include: 1) the procedures were less than adequate because they did not'require wetwell oxygen concentration be verified to be within limits, and 2) management direction was less than adequate to ensure that all Technical Specification surveillance requirements are included'within the Plant procedures.

A contributing cause was a design deficiency of the Containment Monitoring System (CMS-CP-1301 and CMS-CP-1401).

The rationale for each root cause and contributing cause is provided in the following subparagraphs, respectively.

LICENSEE EVENT REPORTkR)

TEXT CONTINUATION AGILITY NAME (I)

Washington Nuclear Plant

- Unit 2 DOCKET NUMBER (2)

LER NUMBER (6) ear umber ev.

No.

AGE (3) 1 05 01 TITLE (4)

OXYGEN CONCENTRATION IN SUPPRESSION CHAMBER WAS NOT VERIFIED PER TECHNICAL SPECIFICATION REQUIREMENTS 4

F 6

a.

During the Power Ascension Testing Program (PATP) of WNP-2 from December 20, 1983, to December 13, 1984, the provisions of Technical Specification 3.6.6.2 were suspended per Special Test Exceptions in Technical Specification Section 3. 10.5.

As a result, there were no procedural requirements to verify oxygen concentration in primary containment during the initial phases of PATP.

When the Plant went into commercial operation on December 13, 1984, procedural requirements were in PPM 7.0.0 to verify oxygen concentration in primary containment.

The drywell and the wetwell are physically separated by the drywell floor. This requires separate gas sampling of each volume.

However, the procedure required only one measurement, and it did not specify which one was required.

Later the procedure was revised to require a drywell measurement only.

b. A systematic overview of the technical specification surveillance. requirements was completed September 6, 1989, which verified there was a Plant procedure for every technical specification requirement paragraph.

However, multiple requirements within a paragraph were not reviewed for procedural compliance.

Therefore, this review would not have identified omission of the technical specification requirement to verify oxygen concentration in the wetwell because the paragraph contained requirements for both the drywell and wetwell.

c.

The current Containment Monitor System control panels (CMS-CP-1301 and CMS-CP-1401) for monitoring oxygen concentration in the primary containment has an automatic sequencing feature that willcontinually sequence through selected sample points within the drywell and wetwell.

The CMS analyzes for both H~ and 0, concentrations and provides output to the Division 1 and 2 recorders, CMS-02R-1 and CMS-02R-2, respectively.

However, the software and related hard-ware that governs that function contain deficiencies that have precluded that feature from being selected since the system was installed in the R-1 Refueling outage in 1985 due to unacceptable maintenance requirements.

Had the software been updated and hardware design deficiencies been corrected to enhance the monitors'perability and ifthe system would have been operated in the automatic sequencing mode, complete primary containment oxygen concentration monitoring would have taken place despite the Technical Specification surveillance omission in the Plant procedures.

Also, an alarm would have actuated in the control room alerting the reactor operator to a high oxygen concentration in the wetwell of three percent, prior to reaching the Technical Specification limitof 3.5 percent.

The primary containment oxygen monitoring system used prior to the current system had a feature to automatically select between the drywell and wetwell. However, the automatic feature was not used.

LICENSEE EVENT REPORTER)

TEXT CONTINUATION AGILITY NAME (I)

Washington Nuclear Plant

- Unit 2 DOCKET NUMBER (2) 0 5

0 0

0 3

9 7

LER NUMBER (6) ear umber ev.

No.

I 05 1

. AGE (3) 5 F

6 TITLE (4)

,OXYGEN CONCENTRATION IN SUPPRESSION CHAMBER WAS NOT'VERIFIED PER TECHNICAL SPECIFICATION REQUIREMENTS

4. As part of the Residual Heat Removal (RHR) System operability surveillance, the suppression pool sprays for RHR Loop B were initiated at approximately 10:25 hours on March 29, 1991.'he sprays were terminated at approximately 11:31 hours on March 29, 1991.

During the period the sprays were operating, the reactor operators acknowledged an annunciator indicating the Reactor Building to Suppression Chamber vacuum breakers, CSP-V-6 and CSP-V-8, were open.

The vacuum breakers open at 0.5 psid.

The operators indicated the vacuum breakers were open only a short time.

Opening of these valves would.have provided the source of oxygen necessary to increase the oxygen concentration in the wetwell. This is the most likely source of oxygen.

Reactor operators have indicated that the vacuum breakers have opened during previous testing of the suppression pool sprays.

B.

her rr ive Ac i n

1. The Supply System has hired an outside contractor to review the Technical Specification surveillance requirements against Plant procedures.

This effort is currently u'nderway and willbe completed in an expeditious manner.

2. Plant Procedure 7.0.0, Shift and Daily Instrument Checks, has been revised.

The CMS is operated with one division continuously monitoring the drywell and other division monitoring the wetwell.

Once each day the channel monitoring the wetwell is selected to the drywell for the required channel check.

Likewise, on a daily basis the channel normally monitoring the drywell is selected to wetwell.

3. Plant procedures were revised to require the reactor operator to log all Reactor Building to wetwell vacuum breaker actuations and specifically monitor wetwell oxygen concentration following an actuation.

S~fi ih The safety significance of this condition is minimal from the standpoint that no accident condition actually existed that required the wetwell oxygen concentration to be less than 3.5 percent.

The probability of occurrence of a design basis accident requiring low wetwell oxygen concentration to maintain containment integrity coincident with wetwell oxygen concentration high enough to actually challenge containment integrity is low.

LICENSEE EVENT REPORT+'R)

TEXT CONTINUATION ACILITY NAME (I)

Washington Nuc1ear P1ant

- Unit 2 00CKET NUMBER (2) 0 5

0 0

0 3

9 7

LER NUNBER (6) ear lumber ev.

No.

I 005 01 AGE (3) 6 F

6 TITLE (4)

OXYGEN CONCENTRATION IN SUPPRESSION CHAMBER WAS NOT VERIFIED PER TECHNICAL SPECIFICATION REQUIREMENTS Similar Fvents There have been several WNP-2 LERs associated with Technical Specification violations.

The most recent similar event was reported in LER 90-007, "Noncompliance with Technical Specification Requirements to Sample for Water in the Diesel Generator Fuel," reported that there was no Plant procedure requirement to check for water in the Diesel Generator Fuel Oil Day Tanks (DO-TK-3A, DO-TK-3B, and DO-TK-3C).

The corrective action from LER 90-007 indicated that reverification of the adequacy of our procedural compliance with Technical Specification requirements will occur as part of the Technical Specification Improvement Program (TSIP).

Implementation of the TSIP Program has been delayed which is the reason for implementing a new corrective action (See Corrective Action No. 2 of this LER).

EII Inform tion R f

~l!<<

f

$gstem

~om onen Wetwell Drywell Containment Monitoring System Control Panels (CMS-CP-1301 and CMS-CP-1401)

Containment Monitoring System Recorders (CMS-02R-1 and CMS-02R-2)

, Diesel Generator Fuel Oil Day Tanks (DO-TK-3A, -3B, and -3C)

Residual Heat Removal System Suppression Pool Vacuum Breakers (CSP-V-6 and CSP-V-8)

Suppression Pool Sprays Seismic Recorder Transmitter (SEIS-RSRT-1)

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