ML17206A594

Loop Current Step Response Tests to Date Indicate That Time Constants of Resistance Temp Detectors Are All Less than 8.0 Second Limit Specified by Tech Specs.No Evidence of Generic Trend to Increase Time Constants for Sensors

ML17206A594
Person / Time
Site:	Saint Lucie
Issue date:	01/03/1979
From:	Robert E. Uhrig FLORIDA POWER & LIGHT CO.
To:	Reid R Office of Nuclear Reactor Regulation
References
L-79-2, NUDOCS 7901090199
Download: ML17206A594 (6)

Text

BEGULATQY INFOBNATION DISTBIBUTIOIYSTEII (BIDS)

ACCESSION NBR -7901090.1 99 DOC.DATE- 79/01/03 NOTARIZED- NO DOCKET Py FACIL:50-335 SAINT LUCIE Ol, FLORIDA POHER 8 LIGHT CO.. 05000335 AUTH. NAME AUTHOR AFFILIATION UHRIG,R.F. FLORIDA POWER 8, LIGHT CO.

RECIPE NAME RECIPIENT-AFFILIATION REID, B.W. '**OPERATING REACTORS BRANCH 4 SUBJECT- Loop Current Step Response tests to date indicate that time constants of RPS RTD's are all less that 8.0 second limit specified by Tech Spec Table 3.3-2, 8, there is no evidence of generic trend to increasing, time constants for sensors.

DISTRIBUTION CODE: A001S COPIES RECEIVED-LTB + ENCL ~ SIZE:

TITLE.- GENERAL DISTRIBUTION FOB AFTER ISSUANCE OF OPERATING LIC NOTES-RECIPIENT COPIES REC I PI ENT, COPIES ID CODE/NAME LTTB ENCL ID CODE/NAME LTTB ENCL

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FLORIDA POWER & LIGHT COMPANY January 3, 1979 L-79-2 Office of Nuclear Reactor Regulation Attention: Mr. R. W. Reid, Chief Operating Reactors Branch b4 Division of Operating Reactors U. S. Nuclear Regulatory Commissi on Washington, D. C. 20555

Dear Mr. Reid:

gTO~~ DD"'~t'.T Re: St. Lucie Unit 1 Docket No. 50-335 Resistance Tem erature Detectors This letter gives the status of the Florida Power & Light Company (FPL) veri fication program for the Loop'urrent Step Response (LCSR) technique of measuring Resistance Temperature Detector (RTD) time constants at St. Lucie Unit l.

In January, 1978, the surveillance required by Technical Specification 4.3.1.1.3 was performed by an FPL consultant on the Reactor Protection System (RPS) Channel A RTD's. The test results were discussed with members of the NRC staff during several telephone conversations. As a result of the discussions, and in accordance with our letter L-78-180 of May 19,'978, available spare RTD's were installed (in May) in place of the four Channel A RTD's and were tested by the LCSR method during the startup of Cycle 2. In further conformance with our May 19 letter, surveillance testing of all 16 RTD's supplying input to the RPS was performed in October, 1978. The results of these tests are tabulated below:

Time Constant seconds Ta No. Januar 1978 Ma 1978* October 1978 TE-1112CA 4.0 + 0.2 4.2 + 0.4 4.0 + 0.4 TE-1112HA 6.2 + 0.5 4.4 + 0.3 4.4 + 0.2 E-1122CA 5.5 + 0.2 5.7 + 0.3 6.0 + 0.6 E-1122HA 5.0 + 0.5 5.6 + 0.3 5.3 + 0.5 E-1112CB 5.0 + 0.5 E-1112HB 5.0 + 0.9 E-1122CB 5.9 + 0.3 E-1122HB 5.8 + 0.3 E-1112CC 4.5 + 0.7 E-1112HC 5.4 + 0.4 E-1122CC 5.4 + 0.3 E-1122HC 5.4 + 0.4 E-1112CD 4.8 + 0.3 ~0 E-1112HD 4.9 + 0.5 E-1122CD E-1122HD 5.7 + 0.5 4.3 + 0.5 ~0

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Office of Nuclear Reactor'Regulation Page Two Comparison of the May test results (replacement sensors) with the January test results (original sensors) shows an apparent improvement in only one of the four time constants. Comparis'on of the October test results with the May test results indicates that there was no significant change in the measured time constants of the four Channel A PTD's during the 5-month interval between tests.

In summary, the results to date of LCSR testing at St. Lucie Unit 1 indi cate:

1) The time constants of the RPS RTD's are all less than the 8.0 second limit specified by Technical Specification Table 3.3-2.

2) There is no evidence of a generic trend toward increasing time constants for these sensors.

Very truly yours, Robert E. Uhrig Vice President Advanced Systems and Technology REU/MAS/cpc cc: Mr. James P. O'Rei lly, Region II Harold F. Reis, Esquire

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