ML19220C624
| ML19220C624 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/23/1979 |
| From: | Chris Miller Office of Nuclear Reactor Regulation |
| To: | Hanauer S Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7905110331 | |
| Download: ML19220C624 (2) | |
Text
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MEHCRA!iDD4 FCR:
S. H. Hanauer, Assistant Director for Plant Systems, 055 l
FR31:
C. F. Miller, Rection Leader, Instncentation and Ccntrol h
l Systems Branch, CSS f
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R. M. Satterfield, Chief, Instncentation and Control 4
Systems Branch, DSS SISlECT:
EWIRC:JT4TAL CUALIFICATIGN A!:D INSTRLSENTATION 10 pl FOLLCW THE COURSE CF Mi ACCISENT g1 g
I In response to ycur April 6,1979 renorandum on this subject I believe the
- d following and leave it with you for your censideration.
t2 1.
Envirorr, ental Oualification Enveloce 4
H The envelope for inside contaireent should enempass with esargin all conditions, values and time periods which result from any event analyzed 4
in the SAR. The post accident portion of the envelope should represent r:
a mintraan of thirty days.
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I believe that the same test samle should be qualified using the following sequence. Aging (or precenditioning stress aging), irrddiation.
'l seismic, extreme temperature, pressure, humidity, and cheatcal environnental ccaditions, and then r.ost accident conditions. This sequence should be examined if future evidence supports that another sequen e is core e
realistic and conservative.
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Accepting the fact all other portions of the Cuality Assurance Programs ar= caintained at a high standards level and testing only one sarple of ph equipment is reoutred, it is irperative that the above encoccassing,
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anvelepe and test secuence is used. The enccccassing enveloca is l:1 developed in a cechanistic way stilizing only those events if&ntified 9
and analyzed in the SA2. To cover, to an unknown deqMe, those events which have not been identified nor analyzed in the SAR, additional assurance is provided by including margin and following the above sequence on the j'1 eculpcent tested. It is my belief and judgement that the above methods will cover nearly all unanalyzed events. This accreach or any cther k'{
approach will never cortoletely do this. This is attributed to the hucan facter involved in systan design, installation, and operaticn.
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C. F. Miller
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2.
Things Which Wave To Be Oualified m
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I consider the contairraent nothing :nore than b block box which is in d
ca:r:unication with the cperator cnly through a link called copper wire.
h As unanalyzed events may still occur, infortaation and status presented to the operator should be accurate to establish a careect basis for operator decision caking. Therefore it appears pmdent that the opera-t bility of all equipment inside the contairtaent should be maintained during
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unplanned events in order that the operator can examine all evenues that h4 exist to maintain control to place the plant in a safe condition. Therefore, 9
I believe that all electrical equipmnt located inside the contairrnent h
i should be qualified to the enviroceental qualification envelope indicated
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I in item 1 above. I believe that there is a group of equi!xaent that cculd i
be exem t from the envelope. but a basis for each exemption should be h
provided on a plant by plant case as designs and impler:entation rnay g
l be different.
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3.
R. G.1.97 Iglenentation v
q Ehere should be no doubt in anybody's midd that a genuine effo-t should K
be put ferth analyzing the TMI event and scenario to determine the
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appropriate post accident monitoring parameters and ranges. Some areas one ray consider are radiation, natural circulat4on flow, incore self powered neutron ronitoring, incore temperature, centainment pressure, L
samle 1tne off the top of the vessel, delta pressure across core, contain-aent te@erature, R. C. Temperatures, and contairnent water level. These b
instements I believe should be separate from and in addition to 4ther safety instrunents.
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4.
Backfitting Any consideration fer backfitting at this time is purely speculative except for areas already identified by nSSS in the area of removing the i
pressurizer level signal frun the coincedence pressurizer low level / low R
pressure logic for initiating SI. Another area should be the need for N
innediate feedwater supply.
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DISTRIEUTION:
0 end 4:edur c."F..cw, NRR READING FILE i
ICSB READING FILE C. F. Miller
'e CENTRAL FILE Section Leader g
Instrisnentation and Control Systen:s g<
Branch, CSS F
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