PNO-V-89-030, on 890518,airborne Process Monitors for Reactor Bldg Stack,Auxiliary Bldg Stack & Auxiliary Bldg Grade Level Vent Inoperable.Caused by Computer Controlled Svc Air Purge Valves in Open Position.Possibly Caused by Software Errors

PNO-V-89-030:on 890518,airborne Process Monitors for Reactor Bldg Stack,Auxiliary Bldg Stack & Auxiliary Bldg Grade Level Vent Inoperable.Caused by Computer Controlled Svc Air Purge Valves in Open Position.Possibly Caused by Software Errors

ML20247E910
Person / Time
Site:	Rancho Seco
Issue date:	05/19/1989
From:	Fish R, Garcia E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-89-030, PNO-V-89-30, NUDOCS 8905260371
Download: ML20247E910 (2)

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• O' O PRELIMINARY NOTIFICATION OF EVENT:OR UNUSUAL'0CCURRENCE--PN0-V-89-30 Date: 5/19/89 This preliminary notification constitutes EARLY' notice of events 'of POSSIBLE safety 2or;public interest significance'. The information presented is as initially received lwithout. verification or evaluation, and is basically all that is known by Region V ~

staff.o'n this date..

FACILITY: Sacramento Municipal Utility District ' Licensee Emergency Classification-Rancho Seco Nuclear Generating Station Notification of Unusual Event 14440 Twin Cities Road Alert Herald, CA. 95638-9799 Site Area'. Emergency General' Emergency DOCKET NO. 50-312- X Not Applicable

SUBJECT:

AlkBORNE PROCESS EFFLUENT MONITORS h0T OPERABLE Region V was informed at 1:00 p.m.'PDT, May 18, 1989,-by the licensee's Chemistry Manager that the airborne process monitors for the Reactor. Building Stack (15044), Auxiliary Building Stack (15045),-and Auxiliary Building Grade Level Vent:(15046) were identified as.not being

. operable. When looking for the cause of why one grab sample analysis was reading unexplainably-low, the. licensee found:that the computer controlled service air purge valves for all1three 4

monitors were in the open position. With the purge valves open, the. sample lines are isolated.-

Review of computer stored data indicates that this condition may have existed since a surveillance was performed on April' 25, 1989. Weekly gaseous grab samples are also suspect.

According to the licensee's preliminary evaluation, there~ were no airborne operational releases

.of radioactivity to the environment and no indications of changes in the. radiological operating

. conditions of the plant during this period. The licensee declared the monitors inoperable per Technical Specification 3.16, and initiated compensatory, measures. 'A " Potential Deviation from-

. Quality',' form has been initiated ~ to determine tle root cause of the failed'open valves. At 3:30 p.m. PDT on May.18. 1989, the licensee informed Region V that they have concluded that

the problem is not hardware related and that they believe that it may be software related.

, -The licensee also believes that a contributing cause may be personnel deviation from the procodure.. The licensee repeated the surveillance..and has placed the monitors back in

. service. Additional tests are being planned to determine root cause.

The licensee does not intend to issue 'a press release at this time.

This information is current as of 8:00 a.m. PDT, May 19, 1989. l CONTACT: E. M. Garcia (FTS 463-3750) or R. Fish (FTS 463-3761)

DISTRIBUTION BY 55E0: L' FAX T0: /' '

L Date 05 89 Time 8:157.M. PDT Date 05-19-89 Time 9:00 f.M PDT Chairman Zech EDO RI INPO Comm. Roberts AE0D RII NSAC Comm. Carr PA0 RIII LICENSEE Comm. Rogers SLITP RIV RESIDENT INSP.ECTOR Comm. Curtis NRR HQS. OPERATIONS OFFICER ,,

SECY. NMSS /g l C A'. ARM MAIL TO:

DCS (Original) #

PDR- 01 /

OGC OIA DOT: (Trans.Only, Applicable / ,

ACRS RES State)

GPA- OIE RV FORM 211

• i 8905260372 890519

. sed W M PDR ILE PND-V-89-030 PNU a.

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PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-89-30 Date: 5/19/89 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation, and is basically all that is known by Region V staff on this date.

FACILITY: Sacramento Municipal Utility District Licensee Emergency Classification Rancho Seco Nuclear Generating Station Notification of Unusual Event 14440 Twin Cities Road Alert Herald, CA. 95638-9799 Site Area Emergency General Emergency DOCKET NO. 50-312 X Not Applicable

SUBJECT:

AIRBORNE PROCESS EFFLUENT MONITORS NOT OPERABLE Region V was informed at 1:00 p.m. PDT, May 18, 1989, by the licensee's Chemistry Manager that the airborne process monitors for the Reactor Building Stack (15044), Auxiliary Building Stack (15045), and Auxiliary Building Grade Level Vent (15046) were identified as not being op::rable. When looking for the cause of why one grab sample analysis was reading unexplainably low, the licensee found that the computer controlled service air purge valves for all three monitors were in the open position. With the purge valves open, the sample lines are isolated.

Review of computer stored data indicates that this condition may have existed since a surveillance was performed on April 25, 1989. Weekly gaseous grab samples are also suspect.

According to the licensee's preliminary evaluation, there were no airborne operational releases of radioactivity to the environment and no indications of changes in the radiological operating conditions of the plant during this period. The licensee declared the monitors inoperable per Technical Specification 3.16, and initiated com>ensatory measures. A '" Potential Deviation from Quality" form has been initiated to determine tle root cause of the failed open valves. At 3:30 p.m. PDT on May 18, 1989, the licensee informed Region V that they have concluded that the problem is not hardware related and that they believe that it may be software related.

The licensee also believes that a contributing cause may be personnel deviation from the procedure. The licensee repeated the surveillance and has placed the monitors back in service. Additional tests are being planned to determine root cause.

The licensee does not intend to issue a press release at this time.

This information is current as of 8:00 a.m. PDT, May 19, 1989.

CONTACT: E. M. Garcia (FTS 463-3750) or R. Fish (FTS 463-3761)

DISTRIBUTION BY 5520: FAX T0:

Date 05 89 Time 8:15 A.M. PDT Date 05-19-89 Time 9:00 A.M PDT Chairman Zech EDO RI INPO Comm. Roberts AE0D RII NSAC Comm. Carr PA0 RIII LICENSEE Comm. Rogers SLITP RIV RESIDENT INSPECTOR Comm. Curtis NRR HQS. OPERATIONS OFFICER SECY. NMSS CA. ARM MAIL T0:

PDR 01 DCS (Original)

OGC OIA DOT: (Trans. Only, Applicable ACRS RES State)

GPA OIE RV FORM 211 Revised 8/19/87