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Category:NRC Preliminary Notification of Event/Occurrence
MONTHYEARPNO-III-18-002, Beaver Valley, Davis-Besse, Perry Notification of Bankruptcy Filing by Firstenergy Solutions2018-04-0404 April 2018
PNO-III-18-002: Beaver Valley, Davis-Besse, Perry Notification of Bankruptcy Filing by Firstenergy Solutions
PNO-III-16-004, A - Unplanned Shutdown of Davis-Besse Nuclear Power Station for Greater than 72 Hours - Update2016-09-23023 September 2016
PNO-III-16-004A - Unplanned Shutdown of Davis-Besse Nuclear Power Station for Greater than 72 Hours - Update
ML16257A2032016-09-13013 September 2016
PNO-III-16-004, Davis-Besse Nuclear Power Station, Unplanned Shutdown for Greater than 72 Hours
PNO-III-15-006, Davis-Besse Shutdown Due to Secondary Side Steam Line Rupture2015-05-13013 May 2015
PNO-III-15-006: Davis-Besse Shutdown Due to Secondary Side Steam Line Rupture
PNO-III-14-003, A - Update to Davis-Besse Shield Building Restoration2014-04-28028 April 2014
PNO-III-14-003A - Update to Davis-Besse Shield Building Restoration
ML14050A0262014-02-19019 February 2014
PNO-III-14-003: Davis-Besse Shield Building Voids
PNO-III-13-007, Davis-Besse Shield Building Laminar Cracks2013-09-20020 September 2013
PNO-III-13-007 Davis-Besse Shield Building Laminar Cracks
PNO-III-13-006, A: Davis Besse Preliminary Notification Update Unplanned Shutdown Greater than 72 Hours on June 29, 2013, Due to Trip of Reactor Coolant Pump and Subsequent Discovery of Reactor Pressure Boundary Leakage2013-07-15015 July 2013
PNO-III-13-006A: Davis Besse Preliminary Notification Update Unplanned Shutdown Greater than 72 Hours on June 29, 2013, Due to Trip of Reactor Coolant Pump and Subsequent Discovery of Reactor Pressure Boundary Leakage
ML13184A1762013-07-0202 July 2013
PNO-III-13-006 - Davis Besse Unplanned Shutdown Greater than 72 Hours on June 26, 2013, Due to Trip of Reactor Coolant Pump and Subsequent Discovery of Reactor Pressure Boundary Leakage
PNO-III-11-014, Davis-Besse Shield Building Indications2011-10-20020 October 2011
PNO-III-11-014, Davis-Besse Shield Building Indications
PNO-III-10-011, DAVIS-BESSE Start-Up of Following Repairs of Control Rod Drive Mechanism Nozzle Flaw Indications2010-06-29029 June 2010
PNO-III-10-011 - DAVIS-BESSE Start-Up of Following Repairs of Control Rod Drive Mechanism Nozzle Flaw Indications
PNO-III-10-008, Davis-Besse, Public Availability of Two NRC Employee Differing Professional Opinions Concerning Past Issues at Davis-Besse2010-05-20020 May 2010
PNO-III-10-008: Davis-Besse, Public Availability of Two NRC Employee Differing Professional Opinions Concerning Past Issues at Davis-Besse
PNO-III-10-003, A - Davis-Besse Nuclear Power Station - Update - Davis-Besse Control Rod Drive Mechanism Nozzle Indications2010-04-12012 April 2010
PNO-III-10-003A - Davis-Besse Nuclear Power Station - Update - Davis-Besse Control Rod Drive Mechanism Nozzle Indications
ML1007503172010-03-16016 March 2010
PNO-III-10-003 - Davis-Besse Nuclear Power Station - Davis-Besse Control Rod Drive Mechanism Nozzle Indications
PNO-III-09-005, A: Davis-Besse, Transitory Alert Due to Electric Device Failure (Update)2009-06-29029 June 2009
PNO-III-09-005A: Davis-Besse, Transitory Alert Due to Electric Device Failure (Update)
ML0917706352009-06-26026 June 2009
PNO-III-09-005: Davis-Besse, Transitory Alert Due to Electric Device Failure
PNO-III-06-002, Security Event at Davis-Besse2006-01-23023 January 2006
PNO-III-06-002-Security Event at Davis-Besse
PNO-III-04-008, Davis Besse Issued 08/04/2004 Re Automatic Reactor Shutdown2004-08-0404 August 2004
PNO-III-04-008: Davis Besse Issued 08/04/2004 Re Automatic Reactor Shutdown
PNO-III-04-003, Shutdown of the Davis-Besse Nuclear Power Station Plant for Greater than 72 Hours2004-03-17017 March 2004
PNO-III-04-003: Shutdown of the Davis-Besse Nuclear Power Station Plant for Greater than 72 Hours
PNO-III-03-010, Davis Besse: Fuel Loading2003-02-21021 February 2003
PNO-III-03-010, Davis Besse: Fuel Loading
PNO-III-02-036, Crack Identified in Vessel Head Stainless Steel Liner2002-09-10010 September 2002
PNO-III-02-036: Crack Identified in Vessel Head Stainless Steel Liner
ML0308703762002-09-10010 September 2002
Preliminary Notification of Event or Unusual Occurrence -- PNO-III-02-036
PNO-III-02-016, A; Discrete Radioactive Particles Found Outside the Radiologically Restricted Area, Davis-Besse Update2002-04-24024 April 2002
PNO-III-02-016A; Discrete Radioactive Particles Found Outside the Radiologically Restricted Area, Davis-Besse Update
PNO-III-02-006, B, Davis Besse - Reactor Vessel Head Degradation (Second Update)2002-04-0505 April 2002
PNO-III-02-006B, Davis Besse - Reactor Vessel Head Degradation (Second Update)
ML0235800962002-03-11011 March 2002
E-mail from PN1 to Events, Front, PN1, PN302006, Davis-Besse - Update - Significant Metal Loss Observed in Reactor Vessel Head
2018-04-04
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April 5, 2002 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-III-02-006B 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 Licensee Emergency Classification Davis-Besse Notification of Unusual Event FirstEnergy Nuclear Operating Co. Alert Oak Harbor OH Site Area Emergency Docket: 50-346 General Emergency x Not Applicable
SUBJECT:
REACTOR VESSEL HEAD DEGRADATION (SECOND UPDATE)
DESCRIPTION:
The NRCs Augmented Inspection Team presented the preliminary findings of its review of the reactor vessel head degradation at the Davis-Besse plant in a meeting with the licensee on April 5, 2002, in Oak Harbor, Ohio. The AIT began the inspection on March 12, 2002, after the utility reported that significant corrosion damage had been found while repairs were being made to a control rod drive nozzle in the reactor vessel head.
The team found that evidence of the corrosion damage was present at least as early as 1998 and that the utility missed several opportunities to identify the problem prior to the current refueling outage.
Beginning in 1999, the plant staff observed a gradual increase in the frequency of filter changes required for the containment radiation monitor filter from monthly to every other day. The filter changes were required because of clogging by material identified as corrosion products from reactor cooling system leakage. Boric acid and corrosion product deposits on the containment air coolers also increased.
The utility also failed to properly implement the NRC-required boric acid control program in that reactor vessel head boric acid deposits were not properly removed and indications of reactor vessel head corrosion were not recognized or evaluated. In the 2000 refueling outage significant deposits of boric acid -- different in color and consistency previously associated with reactor cooling system leaks -- were found on the reactor vessel head.
The utility is continuing its review of the root cause of the reactor vessel head damage. The Augmented Inspection Team concurred with the utilitys preliminary evaluation that the reactor vessel wastage was caused by corrosion associated with leakage of primary cooling water containing boric acid due to cracks in the No. 2 and No. 3 control rod drive nozzles. Additional issues remain to be addressed, however, in the utilitys root cause evaluation, including factors affecting the rate at which the cracks and corrosion progressed, the role of deposits left on the reactor vessel head, and a determination of the chemical process involved in the corrosion.
The utilitys evaluation will be presented to the NRC and made publically available when it is completed.
PNO-III-02-006B The State of Ohio will be notified. The information in this preliminary notification has been reviewed by licensee management.
This information is current as of 9:00 a.m. (Eastern Time) on April 5, 2002.
CONTACTS:
Ron Gardner John Jacobson 630/829-9751 630/829-9736
