Source: https://www.nrc.gov/reading-rm/doc-collections/event-status/part21/1999/1999470.html
Timestamp: 2020-04-09 17:05:58
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NRC: Part 21 - 1999-47-0
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LICENSEE: NUSI
SITE: SCIENTECH, INC. EN NUMBER: 36374
DOCKET: EVENT DATE: 10-22-99
RX TYPE: EVENT TIME: 12:00
VENDORS: NOTIFY DATE: 10-29-99
EMERGENCY CLASS: N/A REGION: 1 STATE: MD TIME: 16:05
OPS OFFICER: DOUG WEAVER
PART 21 REPORT
SCIENTECH, Inc.'s subsidiary NUS Instruments, Inc. (NUSI) has determined that a Basic Component, supplied to Carolina Power & Light Robinson Nuclear Plant under CP&L purchase orders 8Q3800CM and 9D3530CJ, contains a deviation that is reportable under 10 CFR Part 21. NUSI became aware of this potential deviation on October 22, 1999. SCIENTECH, Inc's. President was informed October 28, 1999. CP&L is aware of this problem and the components have been removed from service. A formal written report will be provided within 30 days of this notification. The components, Low Level Amplifier M/N:RTL850, P/N:NUS-A002PA-1/3, Rev. 1 (1 ea.) and P/N:NUS-A002PA-1, Rev. 0 (12 ea.), were manufactured by NUSI. These components have been supplied to no other utility for use in Safety Related Systems. NUSI has opened a 10 CFR Part 21 file concerning this component and has numbered it as 21-99-01.
***UPDATE ON 11/23/99 AT 1431 ET FROM PAUL LOCH TAKEN BY MACKINNON***
SCIENTECH, Inc.'s subsidiary NUS Instruments, Inc. (NUSI) formal report as a follow up to the above preliminary notice which was reported to the NRC on October 29, 1999.
AFFECTED FACILITY AND PRODUCT WHICH IS NON-COMPLIANT
The facility is Carolina Power & Light, Robinson Plant. The Basic Component is Low Level Amplifier used to process signals from resistance temperature detectors (RTD). Then module is NUS Instruments Model No. RTL850.
SUPPLYING FIRM IDENTIFICATION
NUS Instruments, Inc., a wholly owned subsidiary of SCIENTECH, Inc.
440 W. Broadway
DESCRIPTION OF DEFECT AND ASSOCIATED SAFETY HAZARD (INCLUDES THE DATE THAT INFORMATION WAS OBTAINED)
NUS Instruments Model RTL850 Low Level Amplifiers were installed in the Robinson Plant at Carolina Power & Light as replacement modules for Hagan Model 118 modules and NUS Instruments Model RTD850 modules due to the RTL's better temperature coefficients.
The modules were being used to monitor primary plant temperatures of the cold and hot logs to provide Tave and DeltaT indications for operators. The lead length compensation circuitry on the RTL converter PC board has its polarity inverted. This results in the output of the RTL, when configured in three wire mode, to read higher than it actually should. The magnitude is dependent upon the range configured, the RTD type, the lead resistance and other factors. This error can result in actions being taken to control the reactor based upon incorrect information. NUS Instruments became aware of this problem on October 2, 1999 and a 10 CFR PART 21 log entry was made with the number 21-99-01 assigned to it.
CORRECTIVE ACTION THAT HAS BEEN OR IS BEING TAKEN
Corrective action for the basic component is to replace the internal RTL, Personality Module (RPM, P/N: NUS-B003PA-3) in all RTL modules with a new RPM built to a revised schematic to correct for the inverted polarity in the PC board.
NUS Instruments has verified through testing that the units equipped with revision 3 RPMs properly compensated for lead length resistance and is confident no recurrence of this problem will occur. All affected utilities have been notified of this problem and all affected components have been recalled (including modules in Non-Safety Related applications)
ESTIMATE OF WHEN CORRECTIVE ACTION WILL BE COMPLETE:
The R2DO (Len Wert) and NRR (Vern Hodge) were notified by the NRC operations officer.