PNO-I-88-101, on 881005,MSIV C Closed Fully During Partial Stoke Testing of Valve,Causing Water Level Decrease in Steam Generator C & Reactor Trip on lo-lo Steam Generator Level. Shutdown Extended to Perform Maint on Valve: Difference between revisions

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{{#Wiki_filter:>.                                                        DCS No:  504P.388105 Date:    October 6, 1988 o                -
l          ' PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-I-88-101 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety                    ;
or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region I
,              staff on this date.
Facility:                                      Li m see Emergency Classification:
Northeast Nuclear Energy Company                _
                                                                  , Notification of Unusual Event Millstone Nuclear Station Unit 3                      Alert Waterford, Connecticut                          ___ Site Area Emergency                                f General Emergency X Not Applicable                                      :
 
==Subject:==
UNPLANNED SHUTDOWN IN EXCESS OF 48 HOURS                                                    '
On October 5, 1988, at 1:53 p.m., while at 100*. power, the "C" Main Steam Isolation i
Valve (MSIV) closed fully during partial stroke testing of the valve. The partial                        ,
;            stroke testing was part of a a routine, surveillance. The MSIV-C closure resulted in a water lever decrease (shrink) in th? "C" Steam Generator (SG) and subsequent Reactor /
turbine trip on low-low SG 1evel. The resident inspector responded to the control room and noted that the operators and plant syste'ms responded as expected except that the post-trip cooldown was greater than expected (531 degrees F vice 557 degrees F). The larger than expected coolduwn was attributed to high auxiliary feedwater (AFW) flow in combination with high post-trip steam loads. The licensee is continuing to investigate the event sequence.
,            The licensee is extending the shutdown for maintenance on the "B" main feedwater                        *
;            regulating valve, which was being operated in manual because it had been sticking during operation in automatic. Present plans are to perform all work with the plant
'                                                                                                                    i in hot shutdown and to start-up on October 8, 1988.                                                      i
;            The licensee notified the news media of the shutdown.              The State of Connecticut has been informed.
This information is current as of 9:30 a.m.            (EDT), October 6, 1988.
4 CONTACT:    S. Barber                E. McCabe            L. Bettenhausen                              l
]                        203-442-5357              215-337-5231          215-337-5233 1                                                                                                                      l DISTRIBUTION:
OWFN                  MNBB                H-St.            NL        Mail: ADM:0MB                    :
thairman Zech          KE~dd                XM              MS                DOT:Trans only Comm. Roberts          ARM                  p0R Comm. Carr            OGC                                              NRC Ops Ctr Comm. Rogers                                                                                              i INP0----                                    l SECY      NMS$                                              HSAC----
i                                                                                                                      '
CA        NRR OGC      OIA          Regional Offices
,            GPA      01                                                RI Resident Office                          l PA        SLITP E00                                                          Licensee:
OE
[ReactorLicensees)
Region I Form 83 l
: j.          (Rev. April 1988) as1ot2024o so1006                                                            f
[l ),O ,
I                                PDR    IbE              F,DC                                              os PNO-1-sa-101
      - - -                                _ - ---                                      -}}


{{PNO-Nav|region=I}}
{{PNO-Nav|region=I}}

Latest revision as of 18:42, 17 December 2020

PNO-I-88-101:on 881005,MSIV C Closed Fully During Partial Stoke Testing of Valve,Causing Water Level Decrease in Steam Generator C & Reactor Trip on lo-lo Steam Generator Level. Shutdown Extended to Perform Maint on Valve
ML20155E320
Person / Time
Site: Millstone Dominion icon.png
Issue date: 10/06/1988
From: Barber S, Bettenhausen L, Mccabe E
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
References
PNO-I-88-101, NUDOCS 8810120240
Download: ML20155E320 (1)
v • d • e


>. DCS No: 504P.388105 Date: October 6, 1988 o -

l ' PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-I-88-101 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety  ;

or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region I

, staff on this date.

Facility: Li m see Emergency Classification:

Northeast Nuclear Energy Company _

, Notification of Unusual Event Millstone Nuclear Station Unit 3 Alert Waterford, Connecticut ___ Site Area Emergency f General Emergency X Not Applicable  :

Subject:

UNPLANNED SHUTDOWN IN EXCESS OF 48 HOURS '

On October 5, 1988, at 1:53 p.m., while at 100*. power, the "C" Main Steam Isolation i

Valve (MSIV) closed fully during partial stroke testing of the valve. The partial ,

stroke testing was part of a a routine, surveillance. The MSIV-C closure resulted in a water lever decrease (shrink) in th? "C" Steam Generator (SG) and subsequent Reactor /

turbine trip on low-low SG 1evel. The resident inspector responded to the control room and noted that the operators and plant syste'ms responded as expected except that the post-trip cooldown was greater than expected (531 degrees F vice 557 degrees F). The larger than expected coolduwn was attributed to high auxiliary feedwater (AFW) flow in combination with high post-trip steam loads. The licensee is continuing to investigate the event sequence.

, The licensee is extending the shutdown for maintenance on the "B" main feedwater *

regulating valve, which was being operated in manual because it had been sticking during operation in automatic. Present plans are to perform all work with the plant

' i in hot shutdown and to start-up on October 8, 1988. i

The licensee notified the news media of the shutdown. The State of Connecticut has been informed.

This information is current as of 9:30 a.m. (EDT), October 6, 1988.

4 CONTACT: S. Barber E. McCabe L. Bettenhausen l

] 203-442-5357 215-337-5231 215-337-5233 1 l DISTRIBUTION:

OWFN MNBB H-St. NL Mail: ADM:0MB  :

thairman Zech KE~dd XM MS DOT:Trans only Comm. Roberts ARM p0R Comm. Carr OGC NRC Ops Ctr Comm. Rogers i INP0---- l SECY NMS$ HSAC----

i '

CA NRR OGC OIA Regional Offices

, GPA 01 RI Resident Office l PA SLITP E00 Licensee:

OE

[ReactorLicensees)

Region I Form 83 l

j. (Rev. April 1988) as1ot2024o so1006 f

[l ),O ,

I PDR IbE F,DC os PNO-1-sa-101

- - - _ - --- -

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