ML20092N184
| ML20092N184 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 09/28/1995 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20092N179 | List: |
| References | |
| NUDOCS 9510050063 | |
| Download: ML20092N184 (6) | |
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20666 4 001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0.116 TO FACILITY OPERATING LICENSE N0 NPF-2 AND AMENDMENT NO. 108 TO FACILITY OPERATING LICENSE NO. NPF-8 SOUTHERN NUCLEAR OPERATING COMPANY. INC.
JOSEPH M. FARLEY NUCLEAR PLANT. UNITS 1 AND 2 s
DOCKET NOS 50-348 AND 50-364
1.0 INTRODUCTION
By letter dated August 17, 1994, as supplemented by letters dated June 15 and August 11, 1995, the Southern Nuclear Operating Company, Inc. (the licensee),
submitted a request for changes to the Joseph M. Farley Nuclear Plant, Units I and 2, Technical Specifications (TS).
The requested changes would eliminate periodic response time testing (RTT).from the TS requirements for pressure and differential pressure sensors in Reactor Trip System (RTS) and Engineered Safety Feature Actuation System (ESFAS) instrumentation channels.
The June 15 and August 11, 1995, letters provided clarifying information that did not change the August 17, 1994, application and the initial proposed no significant hazards consideration determination.
2.0 BACKGROUND
The proposed TS changes would eliminate periodic response time testing (RTT) surveillance requirements for the following pressure and differential pressure sensors in RTS and ESFAS channels:
Steam generator water level (Units 1 and 2) - Barton 764 Differential Pressure Transmitter Pressurizer pressure (Unit 1) - Foxboro N-EllGM Gauge Pressure Transmitter Pressurizer pressure (Unit 2) - Barton 763A Gauge Pressure Transmitter Steamline pressure (Units 1 and 2) - Foxboro EllGM Gauge Pressure Transmitter Containment pressure (Units 1 and 2) - Barton 764 Differential Pressure Transmitter /Barton 351 Sealed Sensor Reactor coolant flow (Units 1 and 2) - Foxboro E13DH Differential Pressure Transmitter i
9510050063 950928 PDR ADOCK 05000348 P
. 4 Specifically, the proposed TS amendments would revise RTS Instrumentation Surveillance Requirement 4.3.1.3 and ESFAS Instrumentation Surveillance l'
Requirement 4.3.2.3 to indicate that the response time of each RTS and ESFAS instrumentation channel shall be periodically " verified" versus " tested." The associated Bases section would be revised to state that the total channel i
response time may be verified by either actual response time tests of the entire channel in any series of sequential, overlapping or total channel 1,
measurements, or by summation of allocated sensor response times with actual tests on the remainder of tihe channel in any series of sequential or I
overlapping measurements. The use of allocated sensor response times would
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only apply to the specific sensors identified above.
Allocations for specific pressure and differential pressure sensor response i
times would be obtained from:- 1) historical records based on acceptable RTT (hydraulic, noise, or power interrupt tests), 2) inplace, onsite, or offsite 2
. (e.g., vendor) test measurements, or 3) utilizing vendor engineering i
specifications.
The revised Bases would also indicate that the allocations l
for the sensor response times must be verified prior to placing the sensor in i
operational service and re-verified following maintenance that may adversely j
affect response time, such as replacing the sensing assembly of a transmitter.
In support of these proposed TS changes, the licensee originally submitted Westinghouse Electric Corporation topical report WCAP-13632, Revision 1,
" Elimination of Pressure Sensor Response Time Testing Requirements," dated December 1993.
In response to the staff's request for additional information, Westinghouse Electric Corporation revised WCAP-13632, Revision 1.
The licensee transmitted WCAP-13632, Revision 2, dated August 1995, with its August 11, 1995 letter. The licensee's June 15, 1995 letter provided clarifying information in response to the staff's April 17, 1995 request for additional information.
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. Revision 2 of WCAP-13632 describes Westinghouse Owners Group (WOG) Program MVHP-3040, Revision 1, which was completed as an industry effort to demonstrate that TS requirements to perform periodic RTT of selected pressure i
and differential pressure sensors typically installed in RTS and ESFAS i
instrumentation loops at Westinghouse plants could be eliminated.
The staff approved WCAP-13632, Revision 2, for reference in_ license amendment applications for all Westinghouse pressurized water reactors as documented in the staff's Safety Evaluation (SE) dated September 5, l'995. Joseph M. Farley is the lead plant proposing sensor RTT elimination under WOG Program j
MUHP-3040, Revision 1.
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3.0 EVALUATION The lic' ensee noted that Institute of Electrical and Electronic Engineers (IEEE) Standard 338-1977, " Criteria for the' Periodic Surveillance Testing of Nuclear Power Generating Station Safety Systems,".as endorsed by Regulatory Guide 1.118, Revision 2, " Periodic Testing of Electric Power and Protection
' Systems," dated June 1978, defines a basis for eliminating RTT.
Section 6.3.4 of IEEE. Standard 338 states in part:
Response time testing of 411 safety-related equipment, per se, is not required if, in lieu of response time testing, the response j
time of the' safety system equipment is verified by functional testing, calibration check, or other tests, or both. This is
-acceptable if it can be demonstrated that changes in response time beyond acceptable limits are accompanied by changes in performance characteristics which are detectable during routine periodic i
i tests.
'The licensee stated that WCAP-13632, Revision 2, providas the technical basis for the deletion of periodic RTT of the subject pressure and differential pressure sensors. WCAP-13632, Revision 2, utilized the Electric Power Research Institute (EPRI) failt~e modes and effects analyses (FMEA) as 4
documented in EPRI Report NP-7f43, Revision 1, " Investigation of Response Time Testing Requirements," and WOG similarity analyses to justify the elimination of RTT surveillance requirements for numerous pressure and differential
. pressure sensors, including the specific sensors identified in Section 1.0 of i
this evaluation.
As indicated in WCAP-13632, Revision 2, the basic premise for the elimination of periodic.RTT of pressure and differential pressure sensors installed in RTS and ESFAS channels is that pressure sensor component failures that can cause
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response time degradation will also affect sensor output and, therefore, can be detected during other TS surveillance tests, such as channel checks and calibrations.
In addition, these other surveillance tests are performed more frequently than current response time tests.
Based on this information, WCAP-13632, Revision 2, concludes that RTT is redundant to other TS surveillance i
requirements.
J By SE dated September 5, 1995, the staff approved WCAP-13632, Revision 2, as a basis for the elimination of TS RTT requirements for each of the pressure sensors identified in WCAP-13632, Revision 2.
As described in the staff's SE, the results of the EPRI FMEAs and the WOG sensor analyses indicated that, in 4
general, potential sensor component failure modes associated with sensors identified in WCAP 13632, Revision 2, would not affect sensor response time
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independently-of-sensor output. Therefore, sensor failure modes that have the 1
-potential to affect sensor response time would be detected during the
-performance of other TS surveillance tests.
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' I However, the EPRI results did identify several potential failure modes in l
certain pressure sensors that could. affect sensor response time without-concurrently affecting sensor output. To address these failures modes and i
other generic concerns, the staff stipulated four actions that licensees must i
comit to take, if applicable, when eliminating sensor RTT.
First, the staff's SE stated that licensees must perform a hydraulic RTT prior to installation of. a new transmitter / switch or following refurbishment of the
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transmitter / switch to determine an initial sensor-specific response time value.
In response, the licensee has comitted-to revise applicable plant surveillance test procedures-to stipulate that allocations for pressure sensor response times must be verified by performance of an appropriate RTT prior to placing a sensor in operational service and re-verified following maintenance that may adversely affect sensor response time, such as replacing the sensing assembly of a transmitter. When sensor RiT is required, the resultant pressure sensor response times will be documented in the plant procedure data l
packages. The staff finds this comitment acceptable.
- Secondly, the EPRI FMEAs identified crimped capillaries as a manufacturing /
handling defect that has the potential to affect response times of sensors containing capillaries. As a result, the staff's SE stated that for transmitters and switches with capillary tubes, a RTT must be performed after initial installation and after any maintenance or modification activity that could damage the capillary tubes.
In response, the licensee has comitted to i
revise plant procedures and other appropriate administrative controls to stipulate that pressure sensors utilizing capillary tubes, e.g., containment pressure, must be subjected to RTT after initial installation and following any maintenance or modification activity which could damage the capillary
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tubes. The staff finds this comitment acceptable.
The third and fourth stipulated actions in the staff's SE were included as a I
result of identified failure modes associated with transmitters that have j
variable damping potentiometers and with Rosemount pressure and differential pressure transmitters, respectively. However, these two actions are not c
applicable to the Farley plant because the licensee does not have any variable j
damping transmitters or Rosemount transmitters installed in any RTS or ESFAS application for which RTT is required.
For-systems with a history.of sensing line degradation (e.g., blockage), the licensee stated that the sensing lines will be flushed during each refueling outage as recommended by NUREG/CR-5851, "Long-Term Performance and Aging 4
Characteristics of Nuclear Plant Pressure Transmitters," to mitigate sensing line response time degradation due to blockage that noise analysis RTT techniques would have previously detected.
In addition, the licensee noted that extensive pressure sensor sensing line degradation can be detected by
- channel checks.
The staff. finds the above to be acceptable.
4 The licensee has proposed using allocated sensor response times in accordance with the methodology contained in Section 9.0 of WCAP-13632, Revision 2, to verify total RTS or ESFAS channel response time. Allocations for sensor response times would be'obtained from: 1) historical records based on i
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acceptable RTT (hydraulic, noise, or power interrupt tests); 2) inplace, onsite, or offsite (e.g., vendor) test measurements; or 3) vendor engineering specifications. ' There is no specific recommendation regarding which of these methods to use, although the value will be increasingly more conservative progressing through these methods. Available manufacturer supplied and Westinghouse engineering specification response time values for the subject.
pressure. sensors are shown in Table 9-1 of WCAP-13632, Revision 2.
The total channel response time is obtained by summing the allocated sensor response -
time with the measured response time of the remainder of the channel. This methodology, as described in WCAP-13632, Revision 2, was previously approved in the staff's SE dated September 5, 1995.
4.0 SUP9tARY To meet the guidance of Regulatory Guide 1.118, Revision 2, and IEEE 338-1977, Section 6.3.4, RTT is needed unless it has been shown that changes in the response time of a sensor will be accompanied by changes in performance characteristics which are detectable during routine periodic surveillance
- tests.
The sensor analyses results as referenced by WCAP-13632, Revision 2, concluded that RTT is redundant to other periodic surveillance tests, such as channel checks and calibrations, because these other surveillance tests will detect sensor component failures that cause response time degradation.
Furthermore, these other surveillance tests are performed more frequently than current response time tests.
Based on its review of the plant specific commitments and information presented by the licensee as well as the previous approval of WCAP-13632, l
Revision 2, in the September 5, 1995 SE, the staff agrees that, in general, sensor component failures that can significantly degrade sensor response time can be detected during the performance of other required surveillance tests.
Thus, the staff concludes that other existing TS surveillance requirements for i
the subject pressure and differential pressure sensors provide confidence that i
i the safety function of the plant instrumentation will be satisfied without the need for specific RTT. The staff, therefore, concludes that the licensee's proposal to eliminate the TS RTT requirements for the following pressure and i
differential pressure sensors is acceptable:
Steam generator water' level (Units 1 and 2) - Barton 764 Differential Pressure Transmitter i
Pressurizer pressure (Unit 1) - Foxboro N-E11GM Gauge Pressure Transmitter
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Pressurizer pressure (Unit 2) - Barton 763A Gauge Pressure Transmitter Steamline pressure (Units 1 and 2) - Foxboro E11GM Gauge Pressure Transmitter l
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. i Containment pressure (Units 1 and 2) - Barton 764 Differential Pressure Transmitter /Barton 351 Sealed Sensor l
Reactor coolant flow (Units 1 and 2) - Foxboro E13DH Differential l
Pressure Transmitter 5.0- STATE CONSULTATION In accordance with the Commission's regulations, the State of Alabama official was notified of the proposed issuance of the amendments. The State official had no comments.
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6.0 ENVIRONMENTAL CONSIDERATION
The amendments change the surveillance requirements. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (59 FR 49434 dated September 28,1994). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or l
environmental assessment need be prepared in connection with the issuance of the amendments.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: John Ganiere Date:
September 28, 1995 i
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