ML17303A433

Special Rept 2-SR-87-017:on 870604,reactor/turbine Trip Occurred Due to Low Level Condition in Steam Generator 2. Trip Caused Excessive Feedwater Flow Which Was Attributed to Delay in Closing Economizer Valves

ML17303A433
Person / Time
Site:	Palo Verde
Issue date:	06/09/1987
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00231-JGH-T, 192-231-JGH-T, 2-SR-87-017, 2-SR-87-17, NUDOCS 8706170329
Download: ML17303A433 (4)

Text

REGULA 'Y INFORMATION DISTR IBUTIO~SYSTEM (RIDS)

ACCESSION NHR: 8706170329 DOC. DATE: 87/06/09 NOTARIZED: NO DOCKE FACIL: STN-50-529 Palo Verde Nuclear Station> Unit 2> Arizona Publi 05000529

'UTH. NAME AUTHOR AFFILIATION HAYNES> J. G. Arizona Nuclear Poeer Prospect (formerly Arizona Public Serv RECIP. NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special rept: on 870604'eactor/turbine trip occurred while in Mode 1 due to low level condition in Steam Generator 2.

Notif ication of unusual event terminated at 1: 11 p. m.

Detailed r ept of event mill be submitted bg 870704.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR ENCL SIZE:

TITLE: 50. 73 Licensee Event Report (LER). Incident Rpti etc.

NOTES: Standard i zed p lant. M. Davis'RR: 1Cg. 05000529 RECIPIENT CQP IES REC IP IENT COP lES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 LICITRA E 1 DAVIS' 1 1 INTERNAL: ACRS MICHELSQN 1 ACRS MOELLER 2 AEQD/DQA 1 AEQD/DSP/ROAB AEOD/DSP/TPAB 1 DEDRO 1 NRR/DEBT/ADE 0 NRR/DEST/ADS 1 NRR/DEST/CEH 1 NRR/DEST/ELB 1 NR R /DE ST/ I C SB 1 NRR/DEST/MEB NRR/DEST/MTB 1 NRR/DEST/PSB 1 NRR/DEST/RSB 1 NRR/DEST/SGH NRR/DLPQ/HFB NRR/DLPQ/QAB 1 NRR/DOEA/EAH NRR/DREP/RAB NRR/DREP/RPH R+PM*S/ RH NRR/PMAS/PTSH 1 REG 02 1 RES DEPY GI 1 RGN5 F ILE 01 1 EXTERNAL: EGG.'G GROHt M 5 5 H ST LOBBY hlARD 1 LPDR 1 " NRC 'PDR 1 1 NSIC HARRIS' 1 1 NSIC MAYST G 1 1 NOTES:

TOTAL NUMBER OF COPIES REQUIRED: LTTR 44 ENCL 42

Arizona Nuclear Power Project P.O. BOX 52034 ~ PHOENIX, ARIZONA 85072-2034 192-00231- JGH- TRB/MJC June 9, 1987 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 2 Docket No. STN 50-529 (License NPF-51)

Special Report 2-SR-87-017 File: 87-020-404

Dear Sirs:

Attached please find a Special Report 2-SR-87-017 prepared and submitted a report of Notification of Unusual Event that occurred on June 4, 1987.

If you have any questions, please contact T. R. Bradish, Compliance Supervisor at (602) 932-5300, Ext. 6936.

Very truly yours, J. G. Hay es Vice President Nuclear Production JGH/TRB/MJC/cld Attachment ceo 0. M. DeMichele (all w/a)

E. E. Van Brunt, Jr.

J. B. Martin R. P. Zimmerman R. C. Sorenson E. A. Licitra A. C. Gehr INPO Records Center 870hl70329 870609 PDR ADQCK 05000829 8 PDR

PALO VERDE NUCLEAR GENERATING STATION UNIT 2 Emergency Core Cooling System Actuation Docket No. 50-529 License No. NPF-51 Special Report No. 2-SR-87-017 At approximately 1305 on June 4, 1987, the USNRC Operations Center was notified via the Emergency Notification System of the declaration of a NOTIFICATION OF UNUSUAL EVENT (NUE) for Palo Verde Nuclear Generating Station Unit 2. The NUE was declared pursuant to Emergency Plan Implementing Procedure EPIP-02 which also requires a report to the USNRC following a Safety Injection Actuation Signal (SIAS) generated by low pressurizer pressure due to assumed Safety Injection flow into the Reactor Coolant System.

At approximately 1300 MST on June 4, 1987, Palo Verde Unit 2 was in Mode 1 (POWER OPERATION) at 100 percent power when a reactor/turbine trip occurred due to a low level condition in Steam Generator (SG) 2. The low level in SG 2 resulted in an Auxiliary Feedwater Actuation Signal (AFAS) 1 and 2. A Containment Isolation Actuation Signal (CIAS) and SIAS were received due to low pressurizer pressure. The AFAS, CIAS and SIAS signals represent automatic actuations of Engineered Safety Features (ESF). The cause of the reactor trip has been attributed to erratic Feedwater Control System (FWCS) behavior following an equipment malfunction that occurred during troubleshooting that was being conducted under an authorized work document.

As designed, the reactor/turbine trip caused a Steam Bypass Control System (SBCS) Quick Open on all 8 SBCS valves. The Quick Open followed by an excessive feedwater flow caused the Reactor Coolant System to cooldown and resulted in the pressurizer pressure decreasing to the SIAS and CIAS trip setpoints. The excessive feedwater flow has been attributed to a delay in closing the economizer valves as a result of oscillations in valve position caused by perturbations in the Feedwater Control System.

In accordance with EPIP-02, an NUE was declared as 1305. The NUE was terminated at 1311. A detailed report of this event will be submitted by July 4, 1987 pursuant to the requirements of 10 CFR 50.73.