ML20151Y205
| ML20151Y205 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 07/19/1977 |
| From: | Constable G, Sniezek J, Whitt K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-77-131, NUDOCS 9809180154 | |
| Download: ML20151Y205 (1) | |
Text
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W 3 W PRELIMINARY NOTIFICATION o
July 19,1977 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO
.This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance.
The information presented is as initially received without verification or evaluation and is basically all that is known by IE staff on this date.
- Facility: Commonwealth Edison Company, Zion Unit 2 1DN50-304'), Zion,IL
Subject:
BYPASSING 0F SAFETY SIGNALS During'a surveillance test on July 12, 1977, while in a hot shutdown mode, dummy signals were inserted into the pressurizer level, pres-surizer pressure / steam generator level, and primary coolant flow sensors. This action removed the actual sensor signals and substi.
tuted arti.ficial signals to the protective and control functions including several ECCS initiating functions. This condition existed for approximately 40 minutes when, due to unusual readings on pump seal flows and other signals, the operator requested that the dummy signals be removed.
Immediately the pressurizer level indication dropped to zero. The level was restored to an onscale reading in approximately 10 minutes via the charging pumps. The pressurizer pressure and steam generator levels remained essentially constant c.
during this event.
Calculations indicate that the lowest level reached was in the surge line during the event.
No fuel was uncovered.
It was estimated that 5300 gallons were required to bring the pressurizer level back to its
~
original level of 22 percent.
No damage to any equipment was noted after the levels'were restored to normal.
This PN is being issued because the occur ~ence is considered to be r
unusual and of potential public interest.
No press release was planned by the licensee or Re'gion III.
A Region III inspector and investigator reviewed the event at the site C'
.on July 14-15, 1977 and determined that the plant was functioning in a
[
y.
safe condition.
Region III (Glen Ellyn) received notification of this occurrence by telephone from the plant Operating Engineer, at 5:30 p.m. on July 12, d
1977. Additional information was gathered during the inspection and
$ f the Region III evaluation of the significance of the event was completed g
g on July 18, 1977.
g R
Contact:
KWWhitt, IE x27451 GLConstable IE x27451 JHSniezek, IE x27451 Distribution: Transmitted H St L! O fa ;
E5 Commissioner Kennedy C. C. Kammerer, CA G. F. Murphy, JCAE i
EN Commissioner Gilinsky S. J. Chilk, SECY H. H. Whiteside, SCNR ek 5i Transmitted:
MNBB M Q P Bldg ~M D cy H. R. Myers, HCEE l
SS Bldg M f V
$3 L. V. Gossick, E00 E. G. C se, NRR
'C. V. Smith, NMSS ESS l
S. H. Hanauer, EDO 4-,c90' J. A. Harris, PA
- "~
.W. G. Mcdonald, MIPC Luge (MAIL E. Volgenau, IE T. J. RcTie)rnan, OIA Regio E 2j. ]f.
i R. G. Ryan, OSP H. K. Shapar, ELD m m_,
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