View source for PNO-III-86-041, on 860509,unit Shut Down to Repair Failed Main Steam Line Check Valve on Loop B.Normal Differential Pressure Exceeded by 37 Psig.Unit Expected to Be Shut Down for 48 H

{{Adams
| number = ML20197B730
| issue date = 05/09/1986
| title = PNO-III-86-041:on 860509,unit Shut Down to Repair Failed Main Steam Line Check Valve on Loop B.Normal Differential Pressure Exceeded by 37 Psig.Unit Expected to Be Shut Down for 48 H
| author name = Burgess B, Guldemond W
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION III)
| addressee name = 
| addressee affiliation = 
| docket = 05000295
| license number = 
| contact person = 
| document report number = PNO-III-86-041, PNO-III-86-41, NUDOCS 8605130106
| document type = PRELIMINARY NOTIFICATION OF EVENT OR OCCURRENCE (PNO,, TEXT-INSPECTION &amp; AUDIT &amp; I&amp;E CIRCULARS
| page count = 1
}}
{{#Wiki_filter:PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-III-86-41               Date May 9, 1986 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 III staff on this date.
Facility: Commonwealth Edison Company                Licensee Emergency Classification:
Zion Unit 1                                  Notification of an Unusual Eve    ;
Zion, IL 60099                               Alert                            f' Site Area Emergency Docket No: 50-295                            General Emergency XX   Not Applicable Sub,fect: SHUTDOWN TO REPAIR CHECK VALVE At.3 a.m. (CDT), May 9,1986, the unit was shut down to investigate and repair an apparent failure of the main steam line check valve on'the "B" Loop. Operators determined there was differential pressure of about 40 pounds per square inch (psig) across the IB main steam check valve (normal differential pressure is about 3 psig).
The unit is expected to be shut down for more than 48 hours.           Region III (Chicago) will follow the licensee's course of action.
The resident inspector went to the site and is following.
The State of Illinois will be notified.
l  Rsgion III was first notified of the valve problem at 10 p.m. (CDT), May 8, 1986. This information is current as of 11 a.m. (CDT), May 9, 1986.
  -CONTACT:
{0h B. Burgess b b' W. Gu demand
:              FTS 388-5689                FTS 388-5574 l
L DISTRIBUTION:
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                                  ' a'o=9 PDR du}}

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