L-76-381, Response to Request of 9/30/1976 for Information on Operating Experience with Loose-Parts and Loose-Parts Monitoring System

Response to Request of 9/30/1976 for Information on Operating Experience with Loose-Parts and Loose-Parts Monitoring System

ML18127B141
Person / Time
Site:	Saint Lucie
Issue date:	11/02/1976
From:	Robert E. Uhrig Florida Power & Light Co
To:	Ziemann D Office of Nuclear Reactor Regulation
References
L-76-381
Download: ML18127B141 (7)

Text

NRC FORM 195 U.Q. NUCLEAR REGULATORY Coi'SSION DOCVET NUMBER I2 7GI 50-335 FILE NUMOEA NRC DTSTRIBUTION FoA PART 50 DOCKET MATERIAL FROM: DATE OF DOCUMENT Hr. Dennis L. Ziemann Florida Power &

1fiami, Florida Light Company ll 2 76 DATE AFCEIVED Mr. Robert E. Uhrig 11 5 76 ETTEA QNOTORIZED PROP INPUT FOAM NUMOEA OF COPIES RECEIVED A IG INAI PfUNC LASSIF I ED, One signed COPY DESCRIPTION ENCLOSURE Ltr. re our 9/30/76 ltr....concerning loose-par ts and loose-par ts moni toring sys tems a t Unit No.'l.

(3-P) ACKNOWLEDGED PLANT N@IE:

St. Lucie 'l DO NOT RZMOVZ SAFETY FOR ACTION/INFORMATION 11 8 76 RJL hscTAML'A /tD ~ ASS .NED AD ~

BRANCH CHIEF: Ziemann PROJECT IIAMGER: Silver PRO fANA ~

LIC. ASST.: Diggs INTERNAL 0 ISTRI BUTION REG FIL SYSTEMS SAFETY SITE A HEINEMAN F.NV 0 NA I&E 'CHROEDER BENAROYA OELD JABBOUR GOSSICK & STAFF ENGINEERING IPPOLITO MIPC MACCARRY K RKWOO KNIGHT HANAUER SIIMEIL OPERAT N REACTO S IAQ.E PAfILICKI D JAP FE HILLMAN PRO EC I&NA .EIIEN REACTOR SAFE'IIY OPERA N BOYD ROSS 'F.ISENII P COLLINS NOVAK SHAO HOUSTON ROSZTOCZY BAER PrTrRsON CHECK BUTLER HELTZ If'NDERSON RDfES I IELTEMES AT & I SKOVIIOLT SALTZMAN ~QLLIN RUT13ERG EXTERNAL DISTR IIIUTION CONTROL NUMBER LPDR:Ft. Pierce Fla. HAT IJLB: BROOKIIA~~Q' TIC:

NOMIC.:.

ASI.B:

ACIISJ+CYS 4%4QXAII /. I',N REG, VIE LA PDR CONSULTANTS

~

o ~

ULRIKSONLOINI.

jj 6M PI; /,

Nflc I'OIIM IOII I2 7GI

~ ~ 0 ~

~ + ~

'.O. IIOX 013100, MIAMI, FLORIDA 33101 golgi FLORIDA POWER SI LIGHT COMPANY November 2, 1976 L-76-381

~pl I~r/

Office of Nuclear Reactor Regulation Attention: Mr. Dennis L. Ziemann, Chief Operating Reactors Branch 52 Division of Operating reactors yqO>

U. S. Nuclear Regulatory Commission ~Yo'oi r~

Washington, D. C. 20555 OP'o 9,bio

Dear Mr. Ziemann:

Re: St. Lucie Unit. 1 Docket No. 50-335 Loose-Parts Monito'rin S stem Your letter of September 30, 1976 requested that Florida Power G Light Company provide you with information on operating experience with loose-parts and loose-parts monitoring systems at St. Lucie Unit l. The requested information is attached.

Very truly yours, Vice President REU/MAS/cpc Attachment cc: Mr. Norman C. Moseley Robert Lowenstein, Esquire

/ I/~~ <~5

$g+ISSI0~I1 j'Iato X9 868 HELPING BUILD FLOR IDA

ATTACHMENT LPMS 0 eratin Ex erience at St. Lucie Uni't 1

1. No known events have occurred in which a loose-part was found in our primary loop.

2. The LPMS consists of 8 transducers (2 on the reactor head, 2 on the reactor bottom, and 2 each on the steam generators) and associated charge amplifier and main amplifier modules.

A central control console, located in the control room, has the capability of selecting audio monitoring of any single channel. The full scale sensitivity range is selectable from 1.0 to 10.0 "g's" on each main amplifier.

Alarm setpoints are adjustable as a fraction of full scale sensitivity. An eight channel oscillographic strip chart recorder is available for simultaneous hard copy recording of the output from all installed channels. The recorder can be set to automatically actuate when any setpoint is exceeded. The LPMS has been in continuous monitoring operation since late March, 1976. However, Unit 1 has been shutdown since early July, so a large part of the LPMS operating experience has been with a primary system in the refueling mode. Also, one channel was inoperable for practically all of the March-July period due to excessive signal noise, even though attempts were made to repair the channel.

3. Due to the abbreviated period of Unit 1 power operation (none of which was at 100% power), suitable LPMS alarm setpoints have not been developed. Also, there are several indications that the selection of appropriate alarm setpoints will be difficult:

(a) preliminary vendor review of impact test data indicates that alarm setpoints need to be low

(+0.5 g above background noise) to be meaningful, (b) setting alarms just above observed background noise levels (per manufacturer's recommendations) has resulted in frequent spurious alarms, and (c) it has been observed that background noise varies with power level.

There have been no known events which should have but did not cause an indication of loose parts in the primary loop.

1 h

l

(

fi II

The initial cost of our LPMS was approximately $ 50,000, not including the cost of installation. To date we have derived no specific benefit from the LPMS. Based on our operating experience, we feel that the current LPMS does not provide worthwhile additional protection to the public health and safety and that further work is needed to develop an operationally useful LPMS sufficiently free of maintenance and spurious 'alarms.