ML17300A868

Special Rept 2-SR-87-014:on 870426,radioactive Gaseous Effluent Monitors RU-144 Inoperable for More than 72 H. Caused by Test Performance & Subsequent Gm Detector Failure. Monitor Will Be Returned to Svc by 870529

ML17300A868
Person / Time
Site:	Palo Verde
Issue date:	05/22/1987
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00216-JGH-T, 192-216-JGH-T, 2-SR-87-014, 2-SR-87-14, NUDOCS 8706010081
Download: ML17300A868 (4)

Text

<$ ACCESSION NBR: 8706010081 DOC. DATE.: 27/05/22 NOTARIZED: NO DOCKET FAC IL: STN-50-529 Pal o AUTHOR AFFILIATION i

Verde Nuc 1 ear Stat on> Uni t 2> Ari zona Pub 1 i 05000529 AUTH. h}Ah}E HAYNES> S. G. Ari z ona Nuc 1 ear Pouer Pro Ject ( f ormer lg Ari zona Public Serv RECIP. NANE RECIPIENT AFFILIATION Document Control Branch (Document Control Desk )

SUBJECT:

Special Rept 2-SR-87-014: on 870426 Radi oactive Qase ous Effluent Nonitor RU-144 exceeded 72 h limit for inoperability. Caused bg performance of surveillance test.

RU-144 vill be returned to svc bg 870529.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR ENCL SIZE:

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

NOTES: Standardized plant. h}. Davis> NHR: 1Cg. 0500052C>>

RECIPIENT COP I EB REC IP I ENT COPIES ID CODE/NANE LTTR ENCL ID CODE/NA}'}E LTTR ENCL PD5 LA 1 PD5 PD 1 LICITRA, E 1 DAVIS> h} 1 I tdTER NAL: 'CR B NI CHELBON 1 ACRS NOELLER 2 2 AEOD/DOA 1 AEOD/DSr /RO*B 2 2 AEOD/DSP/TPAB 1 1 DEDRO 1 h!RR/DEBT/ADE 0 NRR/DEBT/*DB 1 0 RR/DEBT/CFB t!RR/DEST/ELB 1 1 NRR/DEBT/ ICBM 1 t!RR/DEBT/NEB 1 NRR/DEBT/NTB NRRIDEST/PSB 1 NRr(/DEBT/RBB 1 1 NRR/DEST/SGB 1 1 NRR/DLPG/HFU 1 t-RR/DLPG/GAB 1 1 NRR/DOEA/EAB 1 1 t:.RR/DREP/RAB 1 1 l!RR/DREP/RPB 2 2 LRB 1 1 hjRR/P! }AS/PTSB 1 1 REG FILE 02 1 1 rgEB DEP Y G I 1 I LE 01 1 1 EXTERNAL: EQ8!'} 5 5 H ST LOBB Y WARD 1 LPDR 1 NRC PDR 1 NSIC HARRIS S 1 MSIC NAYS> G 1 1 NOTES:

TOTAL NUNBER OF COP IEB REQUIRED: LT } R 44 ENCL 42

Arizona Nuclear Power Project P.o, BOX 52034 ~ PHOENIX, ARIZONA 85072-2034 192-00216-JGH/TRB/JEM May 22, 1987 NRC Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Palo Verde Nuclear Generating Station Unit 2 Docket No. STN 50-529 (License NPF-51)

Special Report 2-SR-87-014 File: 87-020-404

Dear Sirs:

Attached please find a Special Report 2-SR-87-.014 prepared and submitted pursuant to Technical Specifications 3.3.3.8 and 6.9.2. This report discusses a Radiation Monitoring Unit inoperable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

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

Very truly yours, J. G. Haynes Vice President Nuclear Production JGH/TRB/JEM/cld Attachment cc: 0. M. DeMichele (all w/a)

E. E, Van Brunt, Jr.

J. BE Martin R, P. Zimmerman R. C. Sorenson E. A. Licitra A. C. Gehr INPO Records Center 870601008i 870522 05000529 PDR ADOCK PDR

PALO VERDE NUCLEAR GENERATING STATION Radiation Monitoring Unit Inoperable for Greater Than 72 Hours License No. NPF-51 Docket No. STN 50-529 Special Report 2-SR-87-014 "

This Special Report is being submitted pursuant to Technical Specification 3.3.3.8 ACTION 42b and Technical Specification 6.9.2 to report an event in which Radioactive Gaseous Effluent Monitor (Plant Vent System High Range Monitor) RU-144 was inoperable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limit for operability was exceeded at approximately 0838 MST on April 26, 1987. Pursuant to Technical Specification 3.3.3.8 ACTION 42a the Preplanned Alternate Sampling Program was initiated to monitor the Condenser Evacuation System.

At approximately 0838 MST on April 23, 1987, Palo Verde Unit 2 was in Mode 1 (POWER OPERATION) when the Radioactive Gaseous Effluent Monitors Plant Vent System, low range RU-143 and high range RU-144, were declared inoperable for performance of Surveillance Test 36ST-9SQ07 (Radiation Monitoring Calibration Test for New Scope Process Monitors).

During the performance of 36ST-9SQ07, RU-143 channel 1 detector could not be adjusted to required specifications and the check source did not satisfy the requirements of the surveillance test.

Monitors RU-143 and RU-144 work as a pair with RU-143 being the low range monitor and RU-144 being the high range monitor. Normal configuration consist of RU-143 operating and RU-144 in standby. When RU-143 reaches it's maximum range, RU-144 starts and RU-143 goes to standby. Since RU-143 and RU-144 work in tandem, both monitors must be declared inoperable if the other malfunctions.

Troubleshooting and repair was performed in accordance with an approved work control document. The RU-143 detector was calibrated and returned to its cave assembly in RU-143 at which time the background counts increased beyond specification. Further troubleshooting revealed a difference in resistance from the chassis'round to the signal ground. A temporary modification was installed which lowered the background counts. The temporary modification consists of a jumper from chassis ground to signal ground. This jumper will have no abnormal effects on this monitor's operation or other equipment.

An isolated grounding system for the Radiation Monitoring system is currently being installed in Unit 1 as a corrective measure in response to other events which have occurred at Palo Verde. An evaluation of the effectiveness of the grounding system will be conducted and a decision made at the conclusion of the evaluation for feasibility of installation into Units 2 and 3.

Troubleshooting of the check source did not reveal any problems. The check source was activated and data was satisfactory for completion of the surveillance test.

Special Report 2-SR-87-014 Page 2 When Surveillance Test 36ST-9Sg07 was continued, it was found that RU-144 channel 4 detector would not read the minimum counts per minute when exposed to an 80 microcurie source. The detector was replaced and now reads satisfactorily.

Subsequent to the completion of the Channel Calibration, during the channel functional check RU-144 channel 2 failed to respond to the check source. Investigation revealed that the G-H detector had failed. Parts are currently on order for rework of the detector for RU-144. RU-144 will be returned to service upon completion of the rework.

RU-143 is expected to be returned to service by May 29, 1987.