ML17272B044

PNO-79-77:review of Operational & Sys Problems Identified During TMI Incident.Notes Probable Generic Problem W/ Automatic Safety Injection in Westinghouse & C-E Plants

ML17272B044
Person / Time
Site:	Crane
Issue date:	04/10/1979
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML17272B045	List: ML17272B044
References
PNO-79-77, NUDOCS 7904170306
Download: ML17272B044 (3)

Text

A'4~

+~~$ 7

~ EJ eN

%V/

I PRELIMINARY NOTIFICATIOH

&1

..ra a'e 'r ri i

i<JJr 'aeier i~A~."t,)

e,ca

3. e'.

~ ~

I V

gQ 7

?.'h%

W4e egin

++ Igli7'a M

'I

~

~

vr".

aPI

~ iP E'rJ e'i~a).J ~

~i>i E

Ef April 10, 1979 PRELIMINARY MOTIF'ICATIOH OF E)ENT OR UNUSUAL OCCURREHCEPiiig-79-77(HRR)

This relimina notification constitutes EARLY notice of event of POSSIBLE safet or uhlic interest siqnificancea T e'iniormat on presented is as irlitia receive w>thout verification or eva uation and is asica a

1 that is known.b NRC staff on this date.

~Faciiit

Ai'i'ight Mater Power Reactor Feei Iitiea

~Sub ect:

REVIEli OF OPERATIOHAL ANO SYSTEM PROBLEMS IOENTIFIEO OURIHG THE THREE'II E ISLAND INCIDENT I

As previous'ly discussed in IE'.Bulletins 79-05 and 79-05A, the Three Nile Island Nuclear Po~er Plant, Unit 2, experienced signif'icant core damage which resulted from a series of events initiated by a loss of feedwater transient and compounded by operational errors.

Pressurizer 1evel indica-tion appears to have been a contributing factor by leading to. erroneous inferences of level in the reactor coolant system.

It has been determined..

that in some Westinghouse designed facilities, coincident low pressurizer, pressure-(Pp) and low pressurizer level (Lp} signals are required to actuate safety injection, and f'urther that preliminary analyses of a smaU break in the pressurizer indicate that.

Lp may remain high while Pp cor tinues to decrease.

In such a case, safety injection would not automatically occur,,

and reliance by the operator on Lp could possibly lead ta erroneous

~

actions..

On April 7, 1979, Mestinghouse advised owners with plants having coincident logic for safety injection signals that operators should manua11y intiate safety injection if Pp drops below the safety injection initiation setpoint.

Available related information is. attached.

The extent to which this and other important aspects of the Three Nile Island accident. are generically appl,icable to >lestinghouse and Combustion Engineering designed reactors is 'still being reviewed, but it has been concluded that further actions should be considered on a priority basis for all light water power reactor, facilities.

Meetings are scheduled to be held on April ll, 1979 with vendors to discuss the extent to which all aspects of the Three Hi1e Island accident have generic applicability to Westinghouse and Combustion Engineering designed reactors so that further appropriate short-term corrective actions can be developed and implemented.

~,

r CONTINUED V9041V 080 V 904170 3 0 6

~S);I r

4T

~

P <<i,

~M'bO

~'~ s J

~~>pg7

.f ContinUed Pa'ge 2

April l0, 1979 P}j0"79-77 HRR

Contact:

. DFRoss, HRR x27373 DGEisenhvt, NRR x27221 J

Distribution:

Transmitted H St ~P J

'". ll'"""

Conmssssoner Bradford S. J. Chi'lk, SECY Comnissionev Kennedy Commissione). hhearne C.

C. Kaumerer, CA Co!!I!issioner Gilinsky (For Distribution) yW Transmitted:

HHBB '.

Bldg J.

G. Davis, IE L. Y. Gossickh EDO'H.

R.

Oento NRR Region T

H.

L. Ornstein, EOO

',R.

O.

OeYoung, NRR RegTpn J. J.

Fovchard*,

PA R. J. Hattson'NRR Region EIr N.

H, Hailer, HPA

V. Stello, t)RR Region Iy

.R.

G.

RJJ an,,

OSP

R.

S.

Boyd, HRR Reoion y H.

K. Shapar',

ELD

!SS Bl'dg

'<~'>

'fNKL)

!H. J. Dirc NESS '. J.

Cummings, OIA THI (IE) Sito YIIZmp/r<g

'S.

Levine, RES ',

Hinogue, SD I

~

Attachment:

As stated (2 pages}

J I

JI J

s ra h

M'h 2sg!Slhle PREL&INARY HOTIFICATlOH h

)(