ML19206A413
| ML19206A413 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/01/1979 |
| From: | Moseley N, Mosely N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Engelken R, Grier B, James Keppler, James O'Reilly, Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML19206A398 | List: |
| References | |
| NUDOCS 7904200017 | |
| Download: ML19206A413 (13) | |
Text
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UNITED STATES 6
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6p M WASHINGTON, D. C. 20535
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&&.; ve E E April,,1979 wf
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E MEMORA:;0UM FOR:
B. H. Grier, Director, Region I
,5 J. P. O'Reilly, Director, Region II ii J. G. Y.eppler, Director, Region III
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K. V. Seyfrit, Director, Region IV R. H. Engelken, Director, Region V FROM:
florman C. Moseley, Director, Division of Reactor Operations Inspection, OIE
@ECT:
IE BULLETIi! 79-05, I!UCLEAR Ii!CIDENT AT THREE MILE ISLAND The subject IE Bulletin should be dispatched for action by April 2, 1979, to all Sal power reactor facilities with an opera. ting license.
Subject bulletin aad enclosures should also be dispatched for inforntion to cll other power reactor facilities with an operating license and to all power reactor construction permit holders.
The text of the Bulletin, Enclosure 2 and draft letters to the licer. sea are enclosed for this purpose. which consists of the.
1, referenced Preliminary Notifications, should be added by the regional
/
office.
The letters to the licensee make the commitment tt forward the h
'.inuing Preliminary l'otifications of the incident.
These should be
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- ' larded as they are received.
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ilorman C. Moseley, Dir mtor
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f Division of Reactor Operations F
Inspection Office of Inspection and Enforcement
Enclosures:
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Draft Transmittal Letters to B E Licensees j
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Druf t Transmittal Letter to all other power fctilities 3.
IE Bulletin !!o. 79-05 I:.
Fa:losure 2, to the Bulletin l
CON. -
D.C. Kirkpatrich, IE G-28180 7004200On h
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Ef! CLOSURE 2 A less of offsite power occurred at Davis-Sesse on !!ovember 29, 1977, which resulted in shrinkage of the primary coolant volume to the degree j
that pressurizer level indication was lost.
A recommendation to convey this inforcation to cert.ain hearing boards resulted in the attached cussion and evaluation of the event.
This discussion includes a review of a loss of feedwater safety analysis assuming forced flow, which predicts dispersed primary system voiding, but,no loss of core cooling.
During the Three Mile Island event, however, the forced flow appears to have been terminated during the transient.
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NCINN FROM l'.EMO'LA'.OU' ESTITLED "CCWEYING SEU IMORMATION TO LICENSISO
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p EO.'3D3 - DFIS-3ISSE UNITS 2 & 3 AND MIDLCD USITS 1 6 2",
DATED STEEETER.
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- RT E, 19 79, FROM J. S. CRESUELL TO J. F.
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50-346/78-06 documented that Inspection and Enforcement Report
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pressuriser level had gone of fscale for approxi=ately five
.3 loss of offsite power event.
I minutes during the Nove=h'ef 29,1977
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There are ser.c indications that other B&W plants cay hava prob-g;l Icas =aintaining pressurizer 1cvel indications during transients, j
In addition, under certain conditions such as loss of f eeduater i
200% power with the reactor coolant punps running the pres-I at d }
surizer nay void. completely.
A special analysis has been per-
'j forned concerning this event.
This analysis is attached as.
Because of pressurizer Icvel maintenance prob-l lehs the sizing of the pressuri:cr nay require further review.
f Also noted during the event was the f act th at Tcold vent off-scale (less than 5200F).
In additica,. it was noted that the and
=akeup fica acnitoring is linited to less than 160 sp l
f th.at nakeup flow may be substantially greater than this value, t l 5
This information should be exacined in light of the reo,uire-
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rents of GDC 13.
It DISCUSSION AND EVALUATION l The arcat at Davis Ecsse which resulted in loss of prc'ssurizer level 4
) indication has been reviewed by NRR and the conclusion was reached j
- t no unreviewed safety question existed.
j ine pressurizer, together vith the reactor coolant naheup systen, is t
- designed to naintain the ' primary systen pressure and water level within j their operational. limits only during nor=al. operating conditions.
] Cooldown transientc, such as 1 css of of fsite power and loss of feed -
l vater, socctices result in pri=ary pressure and volume changes that j are beyond the ability of this system to control.
The analyses of
,j and experience with such translents show, however, that they can be g.1 sustained without compromising the safety of the reactor.
The principal
~ ] concern caused by such transients is. that they night cause voiding 16
(; the primary coolant systch that would lead to loss of ability to ade-gj quately cool the rcactor core.
The safety evaluation of the loss of o f f site poner transient shows that,- though level indication is lost,
- j decrecsc con 2 t eter rc=ains in the precruriner cnd the pressure does not j
i.belc about 1600 psi.
In order for veiding to occur, the pressure cust ij decrmcs: below the saturation pressure corresponding to the systen temgcenture.
1600 psi is the naturction pressure corresponding to j
605 F, which is also the maxinua allor bic core cutlet tcapcrature.
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s olcing in the primary systen (c;: cept:ag tne pressuricer) is prec~ucca j
decrease to saturatica.
A in this case, since pressure does not
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Section~3.
lac c: ety an: lysis for nore severe cooldcun transients, such as the loss of feedvater event, indicates that t're water volume could decrease 1
53 During y(N.. to let's than the systen volu=e exclusive of the pressuri:er.
such an event, the emptying of the pressurizer would be followed by
.r...a,a pressure recuction below the saturation point ano tne to cation or Ffg small voids throughout nuch of the pri=ary system.
This would not
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Qy' result in the loss of core cooling because the voids vould be dispersed
.G.4 ove.r a large volume and forced flow vould prevent them fron coalescing r._1 sufficiently to prevent core cooline.
The hieh pressure coolant S
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nJ ectica e. t=o. s are started aute=ata.cally u.nen the prinary pressure m, a.
[ decreases below 1600 psi.
Therefort, _ry pressure reductien which is
- '. ~ficient to allow voiding vill also result in water injection which i rapidly restore the primary water
- o norn21 levels.
l l For these' reasons, we believe that the inability of the pressuri:cr l and norncl coolant mahcup syste= to control sore transients does not
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Provide a basis f or recuiring more capa city in these systems.
l-
} General Design Criterion 13 of Ap endix A to 10 CF?. 30 receires 1
instrumentation to nonitor variables o.er their anticipated ranges ic r "anticipa ted operational occurrences".
Such occurrences are c?acifically defined to includ: loss of all offsite oever.
The fact o
t.
cold goes. otr scale at 320 : is nct consicerec to oe a ceviation tnat 2 f rca this require =Ient because this indicator is backed up by vite o
range tc:parature indication that e.<tends to a low linit of 50 F.
Scither do ve consider the caheup flow conitering to' daviate since amount of nakeup flow in extecs of 160 gp: does not appear to be ignificant factor in the course of these occurrences.
t
$'The ?.oss of pressuricer water level indication could be considered to deviate from GDC 13,. because t'r.ts icvel indication provides the princip21
- ncans of determining the pri=ar,r coolant inventory.
However, provision l of ~a level indication that would cover all anticipated occurrences may j not be practical.
As discussed ms,ve,.the loss of feedvater event can j lcad to a momentary condition wherci. c.' rea,ningful level exists, 3
7M bacause the entire primary ej stem contains a.stean veter mixture.
E3 9:l, I t' should be noted that the intrs duction to Ao. o. cndix A (last paragrach) t9 recognizes that fulfill:ent of some of the criteria cay not always be Lij! sppropricte.
This introduction also states that departures f rom the h.j Criteria nust he identified and justified.
The discussion of GDC 13
[4in the Dr.vis gesse FSAR lists the watet 2 evel instruntatation, but
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_A. coes not nention the po_ nibility of loss of water level in ication
-; curing transients.
This apparent omission in One catety anzlysis (vill be subjccted to further revice.
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