PNO-V-88-015, on 880221,safety Injection & Containment Isolation Actuation Signals Received Due to Low Pressurizer Pressure Signal.Caused by Incorrect Bypass of Pressurizer Low Pressure Protection When Unit Entered Mode 5

PNO-V-88-015:on 880221,safety Injection & Containment Isolation Actuation Signals Received Due to Low Pressurizer Pressure Signal.Caused by Incorrect Bypass of Pressurizer Low Pressure Protection When Unit Entered Mode 5

ML20149M922
Person / Time
Site:	Palo Verde
Issue date:	02/22/1988
From:	Polich T, Richards S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-88-015, PNO-V-88-15, NUDOCS 8802290265
Download: ML20149M922 (1)

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L PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-88-15 Dat /22/88-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 c.n this date.

FACILITY: ARIZONA NUCLEAR POWER PROJECT Emergency Classification PALO VERDE UNIT 2 XX Notification of Unusual Event DOCKET NO. 50-529 Alert WINTERSBURG, AZ. Site Area Emergency General Emergency Not Applicable

SUBJECT:

UNUSUAL EVENT / REFUELING SHUTDOWN On February 21, 1988, at approximately 0719 MST, with the unit in Mode 5 and cooling down to enter a refueling outage, safety injection (SI) actuation and containment isolation _ actuation signals were received due to a low pressurizer pressure signal.

Th] Safety Injection Tanks (SIT) were isolated, however, the SI signal opened these valv;s, as designed. The SITS injected approximately 10% of the tank volumes'. No pumped injection occurred as all active components were removed from service. No pressure-temperature limits were exceeded nor was the low temperature overpressure prot:ction features challenged. An Unusual Event was declared and terminated at 0802 MST due to the safety injection.

The event occurred because the pressurizer low pressure protection was not correctly bypassed when the unit entered Mode 5.

1 The refueling outage is expected to last 85 days.

\Localmediainteresthasbeexperienced, This information is current as of 11:00 am (PST), February 22, 1988.

CONTACT: S. Richards T. Polich FTS 463-3853 (602)386-3650 DISTRIBUTION BY 5520: FAX T0:

i Date .227A Time , / : J 9' Date Time

! Chairman Zech E00 RI INP0 /19 /

l Conn. Roberts AE0D RII NSAC /1.Fr l

Comm. Bernthal PA0 RIII LICENSEE %' 27 Comm. Carr SLITP RIV RESIDENT INSPECTOR IN Comm. Rogers NRR HQS. OPERATIONS OFFICER /Y

! SECY' NMSS l CA ARM MAIL T0:

l PDR OI DCS(Original) l OGC OIA DOT:(Trans. Only, Applicable S= 'e'

! ACRS RES l GPA l

RV FORM 211 Revised: 8/19/87 8802290265 000222 E-VN-015 PDR ,g ff-3Y