ML20195J695
| ML20195J695 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 06/14/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20195J665 | List: |
| References | |
| NUDOCS 8806290197 | |
| Download: ML20195J695 (5) | |
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o UNITED STATES g
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g NUCLEAR REGULATORY COMMISSION
%j WASHINGTON, D, C. 20655
'+4.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE INSERVICE TESTING PROGRAM AND REQUESTS FOR RELIEF UNION ELECTRIC COMPANY CALLAWAY NUCLEAR PLANT, UNIT 1 DOCKET NO. 50-483 INTRODUCTION Technical Specification 4.0.5 for the Callaway Nuclear Plant, Unit 1, (Callawiy) s'.ates that inservice inspection of ASME Code Class 1, 2, and 3 pumps and valves snall be perfonned in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and Applicable Addenda as required by 10 CFR Part 50, Section 50.55a(g), except where specific written relief has been granted by the Connis-sion pursuant to 10 CFR Part 50, Section 50.55a(g)(6)(i). Certain requirements of applicable Code edition and addenda of Section XI are impractical to perform because of certain plant systems and components designs.
Regulation 10 CFR 50.55a(g)(6)(i) authorizes the Commission to grant relief from these requirements upon making the necessary findings. This Safety Evaluation (SE) contains the NRC staff's findings with respect to granting or not granting reliefs cubmitted as part of the licensee's Inservice Testing (IST) Program.
The Callaway firrt 10-year IST program, Revisions 8 and 9, were found acceptable by the NRC for implementation by letters dated August 19 and October 26, 1987.
Subsequently, Union Elr-tric Company (UE), by letter dated April 12, 1988, sub-mitted Revision 10 of the first 10-year IST program and additional information related to requests for relief from certain code requirements which they deter-mined to be impractical to perform on Callaway.
Following a telephone conversa-tion on April 29, 1988, the licensee, by letter dated May 5,1988, resubmitted the relief requests to include additional infonnation as requested.
Revision 10 of Callaway's IST program involves c'e added and two revised relief requests, a change of stroke time for twelve valves, and a change of status of two valves from nassive to active. The program for the first 10-year interval is based on the requirements of the 1980 Edition through the winter of 1981 Addenda of Sec-tion XI of the ASME code and these requirements remain in effect until December 19, 1994.
EVALUATION The IST program Revision 10 and the relief requests from the requirements of Section XI that have been determined to be impractical to perform have been reviewed by the staff and are evaluated below.
In addition, the staff reviewed the other p agram changes and finds them to be acceptable. A sunnary of the relief requests determinations is presented in Table 1.
8806270197 080614 PDR ADOCK 05000483 P
PDH
1.0 PUMPS 1.0.1 RELIEF REQUEST NO. P03 The licensee has requested relief from the flow measurement requirements of Section XI, Paragraph IWP-3100, for the centrifugal charging pumps PBG05A and PBG05B. The licensee proposes to test these pumps quarterly by measuring and trending pump differential pressure and vibration.
In addition, by utilizing an alternate path with installed flow instrumentation, the licensee proposes to measure pump differential pressure, flowrate, and vibration on a refueling frequency and trend against a second set of reference values established at or above the pumps' design flow point (approxinately equal to 462 gpm).
1.0.2 LICENSEE'S BASIS FOR REQUESTING RELIEF Technical Specification 4.5.2.f.1 states, "Each ECCS Subsystem shall be demon-strated OPERABLE by verifying that each centrifugal charging pump develops a discharge pressure greater than or equal to 2390 psid on recirculation flow when tested pursuant to SMcification 4.0.5."
Testing of these pumps is performed on the fixed resistance mini-flow path (approximately equal to 2500 psid, 60 gpm).
At this flow rate, the pump curve for these pumps is relatively flat (approx-imately equal to 25 psid/60 gpm).
Flow rate changes of !50% would result in less than a 1% change in pump differential pressure.
Based on this, the licensee does not feel it is warranted to install additional instrumentation to ensure flow is maintained at the same point ( 2% accuracy) for each quarterly test. Adequate flow is verified for protection of the pumps by monitoring the discharge pipe temperature changes.
To further verify pump performance and monitor degradation, the licensee will run an additional test on a refueling frequency, at or above the design flow point for the pumps and monitor pump flow rate, differential pressure, and vibration.
The flow mcasurement to be perfomed during these outages will be done utilizing an alternate flow path which is only available during outage conditions and has installed flow instrumentation.
This flow instrumentation meets the requirements of ASME Section XI Subsection IWP.
1.0.3 EVALUATION The licensee has demonstrated that it would not be practical tc install instru-mentation in the fixed resistance mini-flow path as there is an alternative flow path with flow instrumentation which is available during refueling outages.
Testing these pumps by utilizing nonnal charging flow is not practical as this could result in pressurizer level perturbations and subsequent reactor shutdown.
Testing during cold shutdown is not practical because of insufficient surge volume which could result in reactor coolant tvstem (RCS) low temperature over-pressurization enncerns. Measuring pump flow rate, differential pressure, and vibration on a refueling outage frequency when an alternate flow path is avail-able is a reasonable alternative to the Code requirements of quarterly measure-ment of pump flow rate. Because of the design of these systems, compliance with the Code would only be possible if the chemical and volume control and high head safety system were substantially redesigned.
Based on the determination that the Code requirements are impractical and considering the licensee's
4 proposed alternative of measuring these pumps' flow rate, differential pressure, and vibration on a refueling outage frequency and the burden on the licensee if the Code requirements were imposed, relief may be granted as requested.
1.1.1 RELIEF REQUEST N0. P09 The licensee has requested relief from the flow measurement requirements of Section XI, Paragraph IWP-3100, for the boric acid transfer pumps PBG02A and PBG02B and proposed to test these pumps quarterly by measuring and trending differential pressure and vibration.
In addition, by utilizing an alternate flow path with installed flow instrumentation, the licensee proposes to m asure pump differential pressure, ' low rate and vibration on a cold shutdown frequency and trend against a second set of reference values established at or above the pumps' design flow point (approximately equal to 75 gpm).
j 1.1.2 LICENSEE'S BASIS FOR REQUESTING RELIEF l
Quarterly testing of these pumps is performed on the fixed resistance mini-flow path (approximately equal to 112 psid, 15 gpm). At this flowrate, the pump curve for these pumps is relatively flat (8 psid/42 gpm).
Flowrate changes of 25% would result in less than a 1% change in pump differential l
pressure.
Based on this, the licensee does not feel it is warranted to install additional instrumentation to ensure flow is maintained at the same point (221 accuracy) for each quarterly test. Adequate flow is verified for protection of the pumps by monitoring discharge pipe temperature changes. To further verify pump performance and monitor pump degradation, the licensee will run an additional test on a cold shutdown frequency, at or above the design flow point for the pumps and monitor pump differential pressure, flowrate, and vibraticn.
The flow measurement to be performed during these outages will be done utilizing an alternate flow path which is only available during outage conditions and has installed flow instrumentation. This flow instrumentation meets the requirements of ASPE Section XI Subsection IWP.
1.1.3 EVALUATION Utilizing the system flow meter quarterly is not possible as this would require injection of highly concentrated boric acid into the RCS which could result in reactor shutdown. The licensee has demonstrated that it would not be practical to install instrumentation in the fixed resistance mini-flow path as there is an alternative flow path with installed flow instrumentation which is only available during cold shut-down. Measuring pump flow rate during cold shutdown is a reasonable alternative to the Code requirements of quarterly measurement of pump flow rate. Because of the design of this system, compliance with the Code requirements is impractical and conformance with the Code would only be j
possible if the boric acid transfer system was substantially redesigned.
Based on the determination that the Code requirements are impractical, and considering the licensee's proposed alternate of measuring these pumps' flow during cold shutdown and the burden on the licensee if the Code requirements were imposed, relief may be granted as requested.
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2.0 VALVES 2.0.1 RELIEF REQUEST NO. V06 The licensee has requested relief from power-op(erated valve stroke time trendingrequi valves BB-PCV-005A and BB-PCV-0456A, whose function is safety related.
The licensee has propsed to apply a maximum stroke time limit of 2 seconds to these valves and to correct them in accordance with IWV-3417(b) if they exceed the limit.
2.0.2 LICENSEE'S BASIS FOR REQUESTING RELIEF The trending requirements of IWV-3417(a) specify that valve test frequencies shall be increased to monthly for valves with stroke times 10 seconds or less when stroke times increased by 50%.
Yalves nonnally stroking rapidly can increase by 50% and show a relatively small numerical stroke time increase, thereby not indicating degradation.
2.0.3 EVALUATION It is not practical to obtain accurate measurements of the stroke times for power operated valves that operate in 2 seconds or less.
Variability of stroke times of rapid acting power-operated valves is frequently a function of the timing method and this variability would not be a reliable indicator of valve degrada-tion.
Following the Code requirements for these valves may result in declaring these valves inoperable unnecessarily.
Based on the design of these valves, the staff has concluded that assigning a maximum stroke time of 2 seconds is a reasonable alternative to the Code requirements for these valves.
The licensee has comitted to declare these valves inoper6ble if the maximum stroke time is exceeded. Therefore, since the Code requirements for these valves are imprac-tical and considering the burden on the licensee if the Code requirements are imposed, and since the licensee's proposed testing is a reasonable alternative to the Code requirements for providing assurance of valve operability, relief may be granted as requested.
CONCLUSION Based on the review of the licensee's IST revisions and relief requests, the staff concludes that the IST program will provide reasonable assurance of the operational readiness of the pumps and valves covered by the IST program to perform their safety-related functions.
The staff has determined that, pursuant to 10 CFR 50.55a(g)(6)(1), granting relief where the Code requirements are imprac-tical is authorized by law and will not endanger life or property, or the common defense and security. The staff has also concluded that granting relief is other-wise in the public interest considering the burden that could result if the requirements were imposed on the facility. During the review of the licensee's revised Inservice Testing Program, the staff has not identified any significant misinterpretations or omissions of Code requirements. Thus, the IST program Revisbn 10 transmitted by letters dated April 12 and May 5,1988, is accept-able for implementation.
Relief requests contained in any subsequent revisions may not be implenented unless approved by the staff.
Principal contributor: T.McLellan(EMEB)
Date:
June 14,1988
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CALLAWAY STATION, UNIT 1 o.
SER SUPPLEMENT TABLE 1
SUMMARY
OF RELIABLE REQUESTS RELIEF SER SECTION XI EQUIPMENT ALTERNATE ACTION REQUEST SECTION REQUIREMENT IDENTIFICATION METHOD OF BY NUMBER
& SUBJECT TESTING USNRC P03 1.0.1 IWP-3100 Centrifugal Measure pump Relief measure pump charging pumps flow aate Granted flow rate PBG05A & PBG058 durit j quarterly refueling outages P09 1.1.1 IWP-3100 Boric acid Measuring Relief measure pump transfer pumps flow rate Granted flow rate PBG02A & PBG028 during cold quarterly shutdown V06 2.0.1 IWV-3417(a)
BB-PCV-0455A &
Declare in-Relief corrective BB-PCV-0456A operable Granted action for d'
troke l
power 4 exceeds operated
.eximum valves value 1
l 1
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