ML19246B197
| ML19246B197 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 05/03/1979 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Varga S Office of Nuclear Reactor Regulation |
| References | |
| FOIA-79-98 790603, NUDOCS 7907120656 | |
| Download: ML19246B197 (1) | |
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"ote to:
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Please use this as a resource in your Bulletin response to 06A.
D.Ross,Jr.[
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-n April 25, 1979 Harold R.
Denten, Director Of fice of ::acicar Scactor Regulation U.S. :'uelcar Rcquiatory Ccc.;alscion Washington, DC 20555 Ccar Mr. Denton:
The t:cw York State Energy Offleo has teviewed I.E. Bulletin 79-06A, d;.ted April 14, 1979, and its reco=cndations for Westinghouse proscuri:ed water reactor facilitics, particular.ly as they would apply to Indian Point IIaits 2 and 3 and the R. T. Ginna plant.
Estud on cur review we have identified one itas th at :uy result in a reduction in the cafety ::argin for Indian point Units 2 and 3 m3 one ite2 t:ut hu the potential for adversely affecting all thrco plants.
The iten of greate;t concern is the require.ont in paragraph 3 that states if precurizer level is used in coincidence with pressurizer pressure, the Icv proccurizcr Icy 31 setroint bistables should be tripped cuch that when pressuricor pressure reachos the low setroint, safety injection would be initiated regardless of pressurizer icvel.
The inglentation of this histabic trip creates a condition where the ufoty injection actuation, with an associated unit trip, is susceptibio to initiation by perturbations on a single instrunent tus. A scenario can ta devvicped for Indian Point Units 2 and 3, which share a corron offaite
- w[tchyard, whero an event caused by a natural phenceanon (e.g. lightning stkihing tha grid network) could gene, rate a bus disturhance. T'11s in turn sculd be reflected on the instruaent busses of each unit which so;, ply the logic circuits for safety injection. This rocentary fluctuatica could cc.uce the actuation of a histable on each unit thus tripping the enit and initiating safety injections. Siice both units vould be aligned tar I.E.
~ r a dual pimt trip and accociated loss Calletin 79-06 A, a condition exists o
of cl:ctric generation. This si=ultancous loss of generating e. 7 ability frca both units could place tb,o systcs grid in a situation that vould result,in a i
partial systes blackout and a total loss of off-site pc'rer. ita recognize that cn-site pc.ter *.;culd supply the engineered safeguards equip.:nt; havever, a I
stable Of f-rite pcVer supply cay not be avalle.ble for the reactor crolant 1.=gs.
If this condition vare to exist, the units sculd ta rc.luired to utilize nature.1 circulation for r+-oval of caro heat. Our prelininary evaluation in3iectes that this situation nay be lecs dccirable than ;urnittf re7 tmper-3 until a well a2.y cNration with the origir.al safety injection Ic>;ic t.che planned solution which would : cet the objective of 79-05A is developed, c
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- ' - aten, Dir:r'.or April 25, 1979 Our r.econd co ncern relates to ite:s 7b of 79-06A which raquires that tho high pressure injection system rc:3in in operation for at least 20 ninnten if it is actuated by a low pressure condition.
The low pressure safety injection logic aligned as per 79-06A will increase the rotential for inad.ortent s.3fety injection actuations and hence the increased oper-ction of the yrps near shutof f head conditions. Since these punps o;>erate imder differcat ccnditions than those at Three Mile Island, it appears prudent to revicw the operating time criteria to insure that the imposed specification is not detrinental to the operatien of these high pressure injection pu ps, with consccp:ent reduction in the safety of the plant.
It is rcT ested that careful censideration be given to theso specific concerns to insure that the universal application of the directive will not, under certain conditions, have a negativo inpact on the safety of thcse plants. While e::paditious changes y be necoscary, they should be the result of a thcrough, wall evaluated decision prococs to insure that the desired effect in indeed cbtained.
Sincer
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T. K. DeEocr Director of Nuclear Operations oc/TDB cc Doyce rf. Crier William J.
Cahill, Jr.
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