ML20073F585
| ML20073F585 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom, Limerick  |
| Issue date: | 09/22/1994 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-90-001, IEB-90-1, NUDOCS 9410030181 | |
| Download: ML20073F585 (5) | |
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8 st:tian eupport osparimint l
NRCB 9041, Supplement 1 a
v-PECO ENERGY c
ecco e"e'ov ama "> -
h Nuclear Group Headquarters 965 ChesterDrook Boulevard I
Wayne, PA 19087 4 691 September 22,1994 Docket Nos. 50-277 50-278 50,352 50-353 License Nos. DPR-44 i
DPR-56 NPF-39 NPF85 U.S. Nuclear Regulatory Commission Attn: Document Control Desk i
Washington, DC 20555 Subject Peach Bottom Atomic Power Station, Units 2 and 3 Limerick Generating Station, Units 1 and 2 Supplemental Response to NRC Bulletin 9041, Supplement 1,
' Loss d Ful-OH in Transmitters Manufactured by Rosemount" Gentlemen i
On March 9,1990, the NRC issued Bulletin 9041, " Loss of Ful-OH in Transmitters Manufactured l
by Rosemount,' requesting that holders of operating licensees for nuclear power reactors promptly identify and take appropriate corrective actions for Rosemount Model 1153, Series B and D, and Model 1154 transmitters that may be or have the potential for leaking ful-ou. PECO Energy Company responded to this NRC Bulletin (NRCB) for Peach Bottom Atomic Power i
Station (PBAPS), Units 2 and 3, and Limerick Generating Station (LGS), Units 1 and 2, by letters dated July 13,1990, October 16,1990, and AprH 30,1991.
On December 22,1992, the NRC issued NRCB 9041, Supplement 1 " Loss of Ful.OB in Transmitters Manufactured by Rosemount," to inform addresses of activities taken by the NRC and the industry in evaluating Rosemount transmitters, and to request licensees to take additional action to resolve the Rosemount transmitter loss of ful-og issue. Supplement I to NRCB 9041 requested that recipients review the information contained in the Supplement for l
applicability to their faclities and modify, as appropriate, their actions and enhanced monitoring l
programs as described in NRCB 9041, Supplement 1. This Supplement also required that licensees provide a written respo,me within 60 days after receipt PECO Energy responded to NRCB 9041, Supplement 1, for PBAPS, Units 2 and 3, and LGS, Units 1 and 2, by letter dated March 5,1993, indicating that the Requested Actions delineated in Supplement I have been completed, and that the enhanced monitoring programs at PBAPS and LGS have been modified in response to NRCB 90-01, Supplement 1.
f a n,i n 9410030181 940922 PR ADOCK 05000277 I
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,o September 22,1994 Page 2 NRC8 90-01, Supplement 1, Paquaatad Action 1.c, requested that Bouing Water Reactor (BWR) licensees replace or monitor Rosemount transmitters within the scope of the Bulletin on a i
montNy basis using an enhanced survallance monitoring program, unti the transmitter reaches i
the appropriate pel-month threshold criterion recommended by Ron,emount. However, the NRC l
Indicated that on a case-by-case basis (with some exceptions), licensees may monitor i
transmitters using an enhanced surveulance program at least once per refueling cycle, provided the licensee afford sufficient justification based on transmitter performance in service and its intended safety function This justification should show that a sufficiently high level of reliabilty i
for the function is provided by the redundancy or diversity of the applicable instrumentation and control systems. In addition, the NRC requested that licensees provide a copy of the i
justification for extending the enhanced surveRiance program.
i There are several transmitters installed at PBAPS and LGS that are included in the enhanced monitoring program in which only calibration data is collected, since during normal plant operations, these transmitters operate under saturated conditions and meaningful data cannot be obtained during the routine surveRiances. These specific transmitters are monitored using zero drift trending of calibration data and extended span response checks (except those transmhters that are reverse calibrated).
Subsequently, the NRC conducted plot inspections of the monkoring program being implemented at PBAPS and LGS in response to NRCB 90-01, and requested that we submit tlw appropriate technical justification for extending the enhanced surveRiance monitoring program for the transmitters not being monitored on a montNy basis, as requested in NRCB 90-01, Supplement 1, Requested Action 1.c.
Therefore, in response to the NRC's request and as specified in NRC 90-01, Supplement 1, we are providing the following justification to support extending the enhanced survealance program beyond the montNy test interval to once every refueling cycle for the following Rosemount transmitters designated below which are currently installed at PBAPS and LGS. This justification addresses the applicable transmitters installed at PBAPS and LGS which satisfy the classification criteria delineated in NRCB 90-01, Supplement 1.
PBAPS, Unit 2 and 3 Transmitters System LT-(2)(3)-2-3-73A-D Nuclear Bouer Vessel Instrumentation The A, B, C, and D transmitters, identified above, provide a signal cori.6poriding to i
reactor pressure vessel water level for indecation, and the A and B transmitters provide a signal corresponding to reactor pressure vessel water level in order to generate an interlock to prevent inadvertent operation of the containment spray / cooling during an accident condtion untN such time that sufficient reactor pressure vessel water level is i
restored (i.e., approximately 2/3 core coverage). Two (2) redundant trains provide containment spray / cooling capabuty. Containment spray / cooling is manuaNy initiated and provisions are provided to override the low-level interlock.
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September 22,1994 Page 3 Only the A and B transmitters provide information for automatic trip signals for containment spray / cooling A sufficiently high level of reliablity of the associated function is maintained and a high degree of confidence in detecting falure of a transmitter is allorded through a combination of transmitter calibration data monitoring, plant staff awarenees of transmitter loss of fiu-ol symptoms, demonstrated acceptable performance of the transmitters, and the overall performance and redundancy of the associated systerro Transmitter calibration data are monitored as discussed in our original response to Bulletin 90-01, submitted by letter dated July 13,1990. The transmitter calibration data are evaluated to determine if any transmitters are exhibiting symptoms indicative of a i
l loss of ful-ol. The transmitter calibration data is also evaluated to predict, haeart on historical performance, if any transmitter may exceed established criteria prior to the next scheduled surveillance. Plant personnel have been trained and have demonstrated a keen ability to identify potentially failed transmitters, based on sluggish response i
during transmitter survealance. Consequently, we are confident that potential transmitter falures due to loss of ful-oM wHi be detected in a timely manner.
The actual calibration data trends for the four (4) transmitters identified above have been reviewed and no adverse trends indicative of a loss of ful-ol are evident. Each of the transmitters has been in service for approximately 40,000 psi-months. Maximum cumulative drift for each transmitter is less than half of the calculated drift limit.
Consequently, the past performance of these transmitters indicates acceptable performance and transmitters exhibit no symptoms indicative of loss of ful-ol.
System redundancy is provided, since two (2) trains of containment spray / cooling provide this capahulty. Provisions to manually override the low-level signal and manuaHy actuate containment spray / cooling are provided As a result, the overaH redundancy of the containment spray / cooling systems and the manual provisions induded in the j
design, provide a high degree of reliability for the containment spray / cooling system capability.
t LGS, Units 1 and 2 t
Transmitters System PDT-51-2N058A-D Residual Heat Removal System - Low Pressure Coolant injection i
PT-40-2N051B, F. K, and P Main Steam isolation Valve Leakage Contrd System PT-40-1N056 Main Steam isolation Valve Leakage Contrd System PT-40-2N056 Main Steam isolation Valve Leakage Contrd System 4
September 22,1994 Page4 i
The transmitters installed in the Low Pressure Coolant injection (LPCI) system identNied above, function to provide a permissive for the LPCI injection valve to open to support automatic arwinn of the LPCI system, an Engineered Safety Feature (ESF). The transmitters instaRed in the Main Steam isolation VaNo (MSIV) Lankage Contrd System identWied above, function to provide p.. ' 5:: for the manual actuation of the MSIV Lankage Control System. Therefore, these transmitters fan within the criteria specNied in Requested Action 1.c of NRCB 90-01, Supplement 1. During normal plant operations, the output of these transmitters is drfven to saturation and meaningful data cannot be obtained between routine survellances.
A sufficiently high level of reliablity of the amarelated actuation function is maintained and a high degree of confidence in detecting the falure is provided through a combination of transmitter calibration data monitoring, plant monitoring, plant staff awareness of transmitter loss of fill-ol symptoms, demonstrated acceptance performance of the transmitters, and the overaX performance and redundancy of the associated systems.
Transmitter calibration data are monitored as discussed in our original response to Bulletin 90-01, submitted by letter dated July 13,1990. The transmitter calibration data are evaluated to determine if the transmitters are exhibiting symptoms indicative of a loss of fHiel. The transmitter calibration data are also evaluated to predict, based on historical performance, N the transmitter may exceed established criteria prior to the next scheduled survellance. Plant personnel have been trained and have demonstrated a keen abBity to identify potentially fared transmitters, hamad on sluggish response during transmitter surve83ance. In addition, the trip units for the associated channels are observed daly during operator rounds to verNy expected operation of the channel.
Gross faRure d the pressure transmitters can be detected during operator rounds.
Therefore, we are confident that potential transmitter faRure due to loss of fil-ol wil be detected in a timely manner.
The actual calibration data trends for the ten (10) transmitters identified above have been i
reviewed and no adverse trends indicative of a loss of FBI-ol are evident. Each of the transmitters has been in service for approximately 60,000 psi-months. Maximum cumulative drift for each transmitter is approximately half of the calculated drift limit.
Consequently, the past performance of these transmitters indicate acceptable performance and these transmitters exhibit no symptoms indicative of loss of fNiel.
i Four (4) trains of LPCI and two (2) trains of the low pressure Core Spray (CS) system l
are avalable to provide reactor core cooling capablity. A minimum of one (1) train of CS or one (1) train of LPCI wil provide the necessary core cooling capabilty.
Consequently, the overall redundancy of these systems provides a high degree of reliab8lty to ensure automatic actuation d the low pressure core cooling capabRity (i.e.,
FNe (5) trains of the MSlV Leakage Control System are provided to direct leakage past closed MSIVs to the Standby Gas Treatment System (SGTS). One (1) train is provided for each inboard MSlV, and one (1) is provided for aN outboard MSIVs. As a result, the overal redundency of the MSIV Leakage Control System provides a high degree of i
reliability for nanual actuation of the MSIV Leakage Control System.
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September 22,1994 Page5 In summary, we are confident that the enhanced monitoring program being implemented at PBAPS and LGS is capable of providing the necessary operational data for predicting and detecting whether or not any Rosemount transmitter included in the program is experiencing symptoms indicative of a loss of fill-ol.
If you have any questions or require additional information, please do not hesitate to contact us.
Very truly yours, I 1 G. A. Hunger, Jr.
,d Director - Licensing cc:
T. T. Martin, Administrator, USNRC, Region l N. S Perry, USNRC Senior Resident inspector, LGS W. L Schmidt, USNRC Senior Resident inspector, PBAPS b
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