ML20195G551
| ML20195G551 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 09/30/1987 |
| From: | Kido C EG&G IDAHO, INC. |
| To: | NRC |
| Shared Package | |
| ML20153E519 | List: |
| References | |
| CON-FIN-A-6415 EGG-NTA-7841, NUDOCS 8710150112 | |
| Download: ML20195G551 (18) | |
Text
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EGG-NTA-7841 3
DEMONSTRATION OF CONTAINMENT VACUUM /0VERPRES$URE RELIEF VALVE OPERA 81LITY FOR TNE DIABLO CANYON POWER PLANT UNITS 1 AND 2 l
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I C. Kido r
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U.S. NUCLEAR REGULATORY CO*NIS$10N i
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EGG-NTA-7841 I
i DIABLO CA WON POWER Pl. ANT UNITS 1 AND 2 DOCKET NUMBEP", 50-z75 AND 50-323 DEMONSTRATION OF CONTAINMENT VACUUM /0VERPAESSURE RELIEF VALVE OPERABILITY
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I C. Kido i
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l Published September 1987 i
NRR and IE Support Branch NRC Technical Assistance Division EG&G Idaho, Inc.
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i Prepared for the U.S. Nuclear Regulatory Commission Washington, D.C.
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Under DOE Contract No. DE-AC07-76ID01570 j
FIN No. A6415 1
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StM4ARY The Diablo Canyon containment vacuum / overpressure relief valve qualification program has been reviewed by the NRR and I&E Support Branch of EG&G Idahs, Inc., who provide technical assistance to the NRR Division of PWR Licensing-A, Engineering Branch. Demonstration of operability of the containment vacuum / overpressure relief valves, particularly the ability of these valves to close during a design basis accident, is necessary to assure containment isolation. This demonstration of operability is required by Standard Review Plan (SRP) 6.2.4, Branch Technical Position (BTP) CSB 6-4, and 3RP 3.10 for containment purge and vent valves which are not sealed closed during operational conditions 1, 2, 3 and 4 Information contained in the Diablo Canyon Final Safety Analysis Report (FSAR), valve, stress analyses, and supplemental material formed the basis for this evaluation. The methodology used by the applicant to evaluate the 12-inch valves was similar to that previously used for the 48-inch containment purge supply and vent lines. This methodology was evaluated and accepted by the NRC staff in SSER 9, SSER 14 and SSER 31.
Operability of the FCV-662, 663 and 664 valves was based upon fluid dynamic analyses, maintenance and surveillance tests, and envircamental entlyses, which simulated the as-butit configuration and worst case 1 cad cambinations. Stress analyses were performed to consider the effects of a LOCA event.
In summary, we find that the information submitted has demonstrated the altlity of the 12-inch Fisher butterfly valves to close against the buildup of containment pressure in the event of a LOCA/DBA with she condition that the 12-inch valves be limited to a 50 degree opening angle for the life of the plant.
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DIABLO CANYON POWER PLANT UNIT 5 1 AND 2 00*KET NUM8ER5 50-275 AND 50-323 DEMONSTRATION OF CONTAINMENT VACUUM /0VERPRES$URE RELIEF VALVE OPERABILITY 1.
REQUIREMENT Demonstration of operabtitty of the containment vacuum / overpressure relief valves, particularly the ability of these valves to close during a design basis accident, is necessary to assure containment isolation.
This demonstration of operability is required by Standard Review Plan (SRP) 6.2.4, Branch Technical Position (BTP) CSB 6-4, and SRP 3.10 for containment purge and vent valves which are not sealed closed during operational conditions 1, 2, 3, and 4 (power operation, startup, hot stsndby, and hot shutdown, respectively).
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As reported in $$ER 9,14, and 31, (Ref. 2, 3, and 4 respectively) the gCstaffreviewedandacceptedtheItcensee'smethodologyfor disonstrating operability of the 44-inch containment purge valves.
Briefly, valve operability was based on a combination of analyses (time history models for LOCA events, valve disc rotation and component stresses) and tests (actuator spring force versus disc opening angle and valve stroke times). The NRC staff found the results of the radiological consequence analyses to be acceptable with one limiting condition. Untti the Itcensee provided evidence to demonstrate operability of the 12-inch vacuum / overpressure relief valves, an interim restriction would be imposed to Itait the disc opening to 50 degrees.
In a submittal dated August 8,1986 the Itcensee demonstrated that the subject valves are qualified for their intended service with the condition
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that the valves be blocked to a maximum 50 degree opening. This valve configuration is consistent with the NRC interim restriction. Diablo Canyon Technical Specification 3.6.1.7 has been revisad to limit the maximum valve opening angle to 50 degrees for the life of the plant. The balance of this report is a discussion and evaluation of the licensee's l
August 8,1986 submittal to qualify the 12-inch vacuum / overpressure reitef valves.
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structural parts of the valve (e.g., valve disc shaft and key).
The msults of the analysts met the 5-second Itatt and allowable stnss criteria (Ref.1, Page 4).
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The disc shaft and key stresses were conservatively calculated by assuming that all of the tapact kinette energy is transferref' as strain energy in the angular deflection of the shaft (Ref.1, Page3).
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The spring force of the actuator cyltador (tacluding nonlinear and frietton effects) as a function of valve disc opening angle was obtained from in situ tests. The test results won used as input to the dynamic analysts (Ref. 1, Page 3).
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The dynamic equation of motion was derived by coupling the flow and disc dynamics to the aerodynamic torque expression provided by the valve manufacturer. The aerodynamic effect acts in a direction to close the valve (Ref. 1 Attachment 1, Page 1).
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In SSER 9 (Ref. 2) the NRC determined that the dose consequences associated with the 48-inch purge valvet meet the dose guidelines i
of 10 CFR 100. The 12-inch relief valves are auch smaller than i
I the 48-inch purge valves and they are blocked to a maximum 50 degree opening.
Consequently, the dose consequences
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associated with use of the 12-inch relief valves provide an even l
greater margin of acceptability (Ref.1 Page 4),
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No credit is taken for downstream backpressure on the design of the valves.
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- 11. No credit is taken for the reduced pressure, lower shaft stnsses, and reduced steam and air losses due to the valves being positioned in series, i,
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We find that the feformation submitted by the Ifeensee has demonstrated the ability of the 12-inch vacuum / overpressure nlief valves FCV-662,'FCV-663, and FCV-664 to close against the bulldup of containment pressure due to a LOCA/DBA. The following considerations fem the basis for our findings, e
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Review of the Diablo Canyon FSAR conff reed that the Ifcensee considered the worst case accident conditions for demonstrating valve operability. The load combinations and assumptions are equal to or knator than the predicted accident.
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The fluid dynamic equations used by the lleensee to calculate dynamic torque developed by the valve are consistent with established industry practices (Ref.1, Attacheent 1). The valve sizing factors and aerodynamic torque expression were obtained from the valve vendor. The vendor data was based on the results of prototype tests performed years ago. The methodology has been 3
reviewed and accepted for use by the industry.
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The licensee has not taken credit for factors that would reduce the incident pressure and differential pressure across the valve.
4 The subject relief valves are normally closed and an permanently blocked to prevent opening beyond 50 degnes. The administrattve c
controls which govern valve use are consistent with Technical
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3pecifications 3.6.1.7 and 3.6.3 (Ref. 1, Page 2).
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The ndundant inside and outside containment n11ef valves an o separate safety trains and use a spring return actuator which closes on less of air. The valves also close on loss of electrical power. This degree of redundancy indicates that single failures of the hardwan can be tolerated ngardless of 1
the cause of failure (Ref.1 Page 2).
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