ML20079Q702
| ML20079Q702 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 03/02/1983 |
| From: | Held J ENERGY, INC., LAWRENCE LIVERMORE NATIONAL LABORATORY |
| To: | Alberthal G NRC |
| Shared Package | |
| ML17255A413 | List: |
| References | |
| CON-FIN-A-0250, CON-FIN-A-250, RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.1, TASK-TM TAC-44376, TF-351-0812A, TF-351-812A, NUDOCS 8306130083 | |
| Download: ML20079Q702 (6) | |
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ATTACHMENT
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.y:w, LAWRENCE UVERMORE LABORATORY
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ENCLOSURE 2 Selected Operating Reactor Issues Program II Reactor Coolant System Vents (NUREC-00737, Item II.B.1. )
FI!!1.L TEO.-:N'.Cfd. EY!.LUA ION T.~;0RT FCR GINNA Docket Number 50-244 NRO TAC Numbers 44376 Prepared by J. T. Held of Energy Incorporated - Seattle (Subcontract' 4324401) for Lawrence Livemore National Laboratory under contract to the NFC Office of Nuclear Reactor Regulation,' Division of Licensing.
NRC Lead Engineer - Gus Alberthal NOTICE "This report was prepared as an account of work sponsored by the United States Government.
Neither the United States nor the United States Department of Energy, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents tha-its use would not infringe privately-owned rights."
-351/0812a XA Copy Has Been...Shn).
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nRC TAC Numb;r 4376 TECHNICAL EVALUATION REPORT ON REACTOR COOLANT SYSTEtX VENTS FOR GINNA INTRODUCTION
. r e re cuireme~.ts f or rea::or cc:1c.1 sys'er. Ug'. peint vents cre st:1ed in peragiczh (cKIXiii) of 10 CFR 50.M, "Stenderds icr Cc nbustible Ges Control System in Light Water Cooled Power Reactors," and further described in Standard Review Plan (SRP)
Section S.4.12, "Recetor Coolant System High Point Vents," and item II.B. I of NUREG-0737," Clarification of TMI Action Plan Requirements." In response to these and previous requirements, the Rochester Gas and Electric Corporation hcs submitted information in References I through S in support of the vent system at the R.E. Ginno Nuclear Power Plant.
EVALUAT!ON The function of the high point vent system is to vent noncondensible gases from the high points of'the reactor coolant system (RCS) to assure that core cooling during natural circulation will not be inhibited. The Ginna reactor vessel head vent system (RVHVS) provides venting capability from the reactor vessel head while the pressurizer con be vented through the existing power operated relief valves (PORVs). The noncondensible gases, steam, ond/or liquids vented from the reactor vessel head are piped and discharged
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directly to the refueling cavity and the discharges from the pressurizer are piped to the pressurizer relief tonk. The RVHVS is designed to vent a volume of ges at least equal to one half of the RCS volume in one hour. Flow restriction orifices in the RVHVS pcths, however, limit the flow from o pipe rupture or from inadvertent actuation of the vent systern to less.than the capability of the reactor coolant makeup system. Hence, the licensee's compliance with 10 CFR 50.46, "Acceptcnce Criteria for Emergency Core Ccoling Systems for Light Water Nuclear Power Reactors," is not offected by the addition of the RVHVS.
7,i/TE R_o.10 Enc'esure 2 Poae I of 5
The P.VHYS consists of two redundant vent paths from the ' rec:for vessel hecd to the refueling cavity, ecch containing two solenoid-operated volves in series which are remMely controlled from the main control room. Indication of volve position is provided in the main control room by way of reed switches. A degree of redundancy bcs been orovided by powering each RVHVS vent p:th from o seperate ernergency bus, to ensure thet RCS venting ced:bility from the rec: tor vessel head is~rncintained. ' RVHVS velve se:: teck:ge is detec:ed, together with other unidentified RCS leckage, by way of Cof icIn Dent rOdic'io9 o7d sumo level rnOnitorIng In oOcord:n=e with plC~nt ie hnice!
peif;ectien:..
The PORVs, used te v.t tne creasurizer, fun: tion es a p:-t of the
- c. om: tic re a:: r co:::.' sy. tam pressere c mrol system, but een cddition:lly be rnonvally controlled from the main control room. The POP,Vs and blo:k valves receive power from emergency buses and have positive volve position indication in the rnoin control room.
The oortion of each RVHVS path up to end including the second norrnally closed valve forms o part of the reactor coolont pressure boundary and thus must meet reactor coolont pressure boundcry requirements. The licensee has stated that the new piping added between previously existing piping and the flow restriction orifices is ASME Section Ill Cicss I cnd the system beyond the orifices to the second vent volves is ASME Section !!! Class 11, in compliance with 10 CFR 50.55a and Regulatory Guide 1.26. The entire RVHVS is designated Seismic Category I in compliance with Regulatory Guide 1.29. The RVHVS is designed for pressures and temperatures corresponding to the RCS design pressure and temperature.
In addition, the vent system materials are compctible with the reactor coolant chemistry and were fabricated and tested in accordance with ASME Section lit subsections NB, NC, and NF ond plant specifications.
The RVHYS and the pressurizer PORV vent system are also ceceptably separated and protected from missiles and the dynamic effects of postulated piping ruptures.
We therefore conclude that the design of the portions of the RVHV5 up to and including the second normally closed valve conforms to all reactor coolont pressure boundary requirements, including 10 CFP,50.55a and the opplicable portions of General Design Criteric 1, 2, 4,14, 30, and 31. The licensee has further ascericined that the essential operation of other safety-related systems will not be impaired by postulated failures of RVHVS components.
We have reviewed the licensee's RVHVS design to assure on cecepichly low probability exists for inadvertent or irreversible octuation of the vent syste.m. Each vent path has N/Ta< P-10
o two scienoid-operated globe volves in series, and eo:h volve.hes o se;x:rcle key locked control switch. Power is removed from the volves during normol reactor operction. The volves cre powered by emergency power supplies and foil to the closed position in the event of loss of power. The licensee hcs stated that th._.e controls and dispicys added to 9he mein control room for the vent system will b'e considered in a human icetors analysis conducted in occordance with NUREG-07~7 lt em 1.D. l
" Control-Room Design g
Reviews." We therefore find that no single c:tive ee sponent failure or hum:n error sh,vid result in inadvertent opening or foilure to close offer intentione: epening of the RVrWS. However, rece:or vessel head vent velve co:! tion indieci:o is powered from the some poser su: ply which se: piles contro: power. If the licensee's intention is to remeve control power by opening the breakers or removing the fuses rcther then lo: king out power to the volves by the key-lock switches, positive volve position indication will be lost. Until the licensee verifies that the control power breakers will not be maintained open and the fuses will not be removed during normal operation or the licensee provid.es on occeptable alternative method of continuous, direct volve position. indication, this is on open item.
We hcve also examined the locations where the RVHVS normally discharges to the containment atmosphere in the vicinity of the refuelin'g covity.' Besed on a description provided by the licensee (Reference 3), these locations are in areas that assure good mixing with the containment atmosphere to prevent the occumulation or pocketing of high concentrations of hydrogen in compliance with 10 CFR S0.44, " Standards for Combustible Gas Control System in Light Water Cooled Power Reactors." Additionally, these locations are such that the operation of safety-related systems would not be adversely offected by the discharge of the anticipated mixtures of stearn, liquids, and
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noncondensible gases.
l The licensee has stated that the RVHVS volves will be exercised each refueling outage, and proper volve position will be visually verified. Operability testing of the PORVs cnd block volves is specified in the Ginno inservice Pump and Volve Testing Program and is in l
occordorce with Section XI of the ASME Code.
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CONCLUSION We conclude that the Ginna RVHVS cnd. pressurizer._PORV vent system design is sufficient to effectively vent noncondensible gases from the reactor coolant system without leading to on uncecepicble in:reese in the probability of a LOCA or o challenge to contcinment intecritv, meets the design requirements of NUREG-0737 ltem 11.B.1 cnd the e 911::51e portions of General Desig, Criterio I, 2,4,14, 30, cnd 31, and conforms to thy reeviremen:s of p=regt::h (cV3Xiii) of 10 C R S0.44 with one exceptio. concerning
.cerSive volve oosition indic:tico es ne:ed c5:ve. We the.efore recommend followir.;
res.:;ut;c. of this open itern that the Gi. n: RCS ven: sys1em design be fou,d oecepicble. It should be noted, however, that the following items were excluded from the scope of our review: seismic and environmental qualification of the RVHVS, RVHVS operating guidelines and procedures, and required modifications to the plant technical specificctions and in-service inspection program for the RVHVS.
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t/ ALDER-P- ! O En:1osure 2
REFERENCES l.
Lett er, L.D.
White,. Jr.
(Rochester ;Ges and Electric Corporation) to D. L. Ziemann (NRC), Followup Actions Resulting from the NRC Stcff Reviews Regarding the Three Mile Island Unit 2 Accident, R.E. Ginne Nuclear Power Plant, Docket No. 50-2/4," dcted October 17,197*.
2.
- Letter, L.D.
W-he.
Jr.
iRo:hess er Gcs end Electric Co corction) to C. Ziemenn (NRC), 'iThree Mile is cad Lessons Lectned Short Term Rechirements, R.E. Ginne Nucle =r Power Plant, D:>:ket No. 50-244," dcTed December 28,1979.
3.
- Letter, LD.
- White, Jr.
(Rochester Gas and Electric Corporation) to D.Ms. Crutchfield (NRC), "Short Term Lessons Learned, Reactor Coolant System Venting, R.E. Ginna Nuclear Power Plant, Docket No. 50-24," dated June 2,1980.
4.
Letter, J.E. Maier (Rochester Gcs and Electric Corporation) to D.Mu Crutchfield (NRC), "NUREG 0737 Requirements, R.E. Ginnn. Nuclear Power Plant, Docket No. 50-24," dated July 1,1981.
5.
Letter, J.E. Maier (Rochester Gas and Electric Corporation) to D.M. Crutchfield (NRC), " Reactor Coolant System Vents (TMl item II.B.1), R.E. Ginno Nuclear Power Plant, Docket No. 50-2tA" dated May 7,1982.
[ /c/TER_P-10 Enclosurg