Event Notification Report for June 26, 2000

UNIT EXPERIENCED AN AUTOMATIC REACTOR SCRAM FOLLOWING A TRIP OF THE MAIN TURBINE

"MAIN TURBINE TRIP RESULTING IN AUTOMATIC REACTOR SCRAM. ALL RODS INSERTED. TWO MAIN STEAM RELIEF VALVES AUTOMATICALLY OPENED ON HIGH PRESSURE. EMERGENCY OPERATING PROCEDURES WERE ENTERED ON LOW REACTOR LEVEL [+13 INCHES]. BYPASS VALVE #1 OPENED AND STUCK OPEN RESULTING IN REACTOR PRESSURE DECREASE TO APPROXIMATELY 500 PSIG. COOLDOWN RATE WAS NOT EXCEEDED. THE BYPASS VALVE IS CURRENTLY CLOSED. REACTOR WATER LEVEL INCREASED ABOVE LEVEL 8 [+54.5 INCHES]. PRESSURE CONTROL IS CURRENTLY ON SRVs [SAFETY RELIEF VALVES]. LEVEL CONTROL IS CURRENTLY ON CONDENSATE AND BOOSTER PUMPS. ALL SYSTEMS STABLE."

ALL SAFETY-RELATED EQUIPMENT IS AVAILABLE, IF NEEDED. ELECTRICAL LOADS ARE CURRENTLY SUPPLIED BY OFFSITE POWER. ONE TRAIN OF SUPPRESSION POOL [SP] COOLING IS IN OPERATION MAINTAINING SP TEMPERATURE AT 86 DEGREES F. THE LICENSEE IS INVESTIGATING THE CAUSE OF THE MAIN TURBINE TRIP AND FAILURE OF THE #1 BYPASS VALVE TO CLOSE. THERE WAS NO ELECTRICAL MAINTENANCE OR SURVEILLANCE TESTING IN PROGRESS PRIOR TO THE MAIN TURBINE TRIP.

THE LICENSEE INFORMED THE NRC RESIDENT INSPECTOR.

PART 21 REPORT INVOLVING A DESIGN DEFECT IN A SPLIT RING RETAINER (DRAWING B65573)

"This report is written to satisfy the requirements of paragraph 21.21.4. The numbering of the information given here correlates with the numbering in 21.21.4:

(i) Bill Shaffer

Director of Operations
Ingersoll-Dresser Pump
5715 Bickett Street
Huntington Park, CA 90255


(ii) Split Ring Retainer

Drawing B65573 Rev.


(iii) Ingersoll-Dresser Pump
5715 Bickett Street
Huntington Park, CA 90255

(iv) The Split Ring Retainer (Drawing B65573 Rev. 0) specifies a drilled and counter bored bolt hole diameter too large to allow the bolting to secure this retainer in its intended position. Based on an evaluation of this condition, it has been determined that this design defect could allow the subject Split Ring Retainer and other adjacent parts including the Split Ring Retainer bolting, split ring and pressure reducing sleeve to move out of position. This could result in a seal failure or a catastrophic pump failure.

(v) IDP Huntington Park was informed of this defect on 6-22-00.

(vi) Three defective split ring retainers were manufactured. The location of all three are known to IDP-HP. Three were shipped to STP Nuclear Operating Co. One of the defective split ring retainers was installed and put into service at STP.

(vii) On June 23rd Dennis Stark of STP was notified of the defective split ring retainer and that it could result in a catastrophic failure. Replacement split ring retainers with corrected design will be ship[ed] by June 30, 2000.

(viii) IDP-HP advised Dennis Stark of STP that the pump with the installed defective split ring retainer should be taken out of service."

UNIT MANUALLY TRIPPED FOLLOWING A LOSS OF THE "A" MAIN FEEDWATER PUMP (MFP)

AT 1900EDT ON 6/26/00, THE UNIT EXPERIENCED A PLANT SETBACK TO 55% POWER FOLLOWING THE LOSS OF THE "A" MFP. OPERATORS INSERTED A MANUAL REACTOR TRIP AS STEAM GENERATOR LEVELS APPROACHED THE LOW LEVEL TRIP SETPOINT. ALL SYSTEMS FUNCTIONED AS REQUIRED WITH ALL CONTROL RODS FULLY INSERTING. EMERGENCY FEEDWATER (EFW) ACTUATED AS EXPECTED. THE MAIN CONDENSER IS AVAILABLE ACCEPTING DECAY HEAT VIA STEAM BYPASS. NO PRIMARY/SECONDARY SAFETIES/RELIEFS LIFTED DURING THE TRANSIENT. ALL THREE OFFSITE POWER SOURCES ARE AVAILABLE.

THE LICENSEE INFORMED THE NRC RESIDENT INSPECTOR AND WILL ISSUE A PRESS RELEASE.

********** UPDATE AT 0015 ON 06/27/00 FROM DAMON RITTER TO LEIGH TROCINE **********

The licensee updated this event notification to document an abnormal post-trip response and to correct the event time. The following text is a portion of a facsimile received from the licensee:

"Subsequent to the trip, one channel of intermediate and source range nuclear instrumentation did not energize. The cause is under investigation. [The licensee stated that this did not place the unit in a limiting condition for operation because there was still one channel in operation.] Additionally, the event time for the event notification is corrected. The reactor trip was initiated at 1853 [on] 26 June 2000 [in lieu of 1900]."

The licensee plans to notify the NRC resident inspector. The NRC operations officer notified the R1DO (Morris).

LOSS OF A SIGNIFICANT PORTION OF OFFSITE EMERGENCY SIRENS

"NOTIFIED BY EMERGENCY PLANNING PERSONNEL THAT AS OF 2058[EDT] ON 6/26/00, NINETEEN [19] OFFSITE SIRENS HAD BEEN LOST. AS OF 2158[EDT] EFFORTS TO RESTORE ARE STILL IN PROGRESS. OF THE NINETEEN [19], SIXTEEN [16] ARE IN DELAWARE AND THREE [3] ARE IN NEW JERSEY. THE NINETEEN [19] SIRENS REPRESENTS LOSS OF GREATER THAN 25% OF THE TOTAL OF SEVENTY-ONE [71] SIRENS."

THE LICENSEE COULD NOT IDENTIFY THE CAUSE, HOWEVER, THEY ARE CURRENTLY EXPERIENCING ADVERSE WEATHER. THIS REPORT ALSO AFFECTS THE HOPE CREEK STATION. THE LICENSEE WILL INFORM THE NRC RESIDENT INSPECTOR.

********** UPDATE AT 0043 ON 06/27/00 FROM STEVE SAUER TO LEIGH TROCINE **********

At 2340 on 06/26/00, the licensee was notified that the bulk of the offsite emergency sirens (all but three) had been restored to service.

The licensee plans to notify the NRC resident inspector. The NRC operations officer notified the R1DO (Morris).

PRIMARY CONTAINMENT ISOLATION SYSTEM (PCIS) ACTUATIONS DUE TO THE TRIPPING OF ELECTRICAL PROTECTION ASSEMBLIES (EPA) AND SUBSEQUENT HALF SCRAM

The following text is a portion of a facsimile received from the licensee:

"[The unit experienced a loss] of [the] 'A' [reactor protection system (RPS)] bus[. Output] EPAs tripped causing [this 120-volt AC] bus to de-energize. This caused the reactor building ventilation to isolate[,] both [standby gas treatment systems (SBGT)] to start[, and the] 'A' [hydrogen/oxygen (H2/O2)] monitor to trip (PCIS valves). [The reactor water cleanup (RWCU)] system tripped on low flow due to 12MOV-15 closure (PCIS valve)."

The licensee stated that there was nothing unusual or not understood and that all systems functioned as required. The licensee also stated that the cause of this event is currently under investigation. The EPAs tripped under normal supply, and the RPS motor-generator set was functioning properly. There were no maintenance or surveillance activities underway at the time of the event.

The reactor building and H2/O2 analyzers have since been un-isolated. SBGT is currently under normal operation and is being used for venting. RWCU has not yet been restored to normal.

The licensee plans to notify the NRC resident inspector.

NRC BULLETIN 91-01 RESPONSE (24-HOUR REPORT)

The following text is a portion of a facsimile received from Portsmouth personnel:

"At 1240 hours on 06/26/00, it was discovered that a Nuclear Criticality Safety Approval (NCSA) requirement had not been met during sampling and batching operations in the X-710 building. The contents of four polybottles were batched into two five-gallon containers without adequate documentation showing that the sampling data was for Nuclear Criticality Safety purposes. A review of the sample results indicated that all the results did not meet the NCSA requirements for independent measurements. This violated NCSA-PLANT053.A03 requirement #13 which states, 'The results of sample analysis or NDA (Non-Destructive Assay) measurements shall not be used for NCS purposes if the documentation does not show that the results were determined as NCS significant results.' (Basis: The measurements and analysis must be performed to independent criteria to be acceptable for NCS purposes.)"

"Two independent measurements of mass of the batching material are required to ensure double contingency. Only one independent measurement of mass was available. The other measurement did not meet independent criteria per NCSA requirements. The absence of a second independent measurement constituted a loss of one control of the double contingency principle."

"A second independent measurement was performed, and compliance was reestablished with NCSA-PLANT053.A03 at 1557 hours on 06/26/00."

"SAFETY SIGNIFICANCE OF EVENTS: The safety significance of this event is very low. The total U235 involved in each of the two batches [is] 0.2154 grams and 2.1868 grams, respectively. To re-establish NCS compliance, repeat NCS measurements for each batch were performed to confirm that the total mass meets the requirements of NCSA-PLANT013, Batching Solutions and Solids."

"POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO[S] OF HOW CRITICALITY COULD OCCUR): Prior to batching the contents in accordance with NCSA-PLANT013, documentation of analysis results are checked to ensure that the measurements were handled as 'NCS Significant' and independently analyzed in accordance with NCSA-PLANT053. Without independent results, a single measurement error could result in more than a safe mass being batched into a container. If this mass were then subject to the correct geometry, moderation, and reflection conditions, a criticality could occur."

"CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.): Mass is the only controlled parameter. Two independent measurements of mass are required to ensure double contingency. Since independence of NDA mass measurements is called into question, only one independent estimate of mass is available. The absence of a second independent NDA mass measurement represents a loss of one double contingency control."

"ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE OF CRITICAL MASS): The total U235 involved in each of the two batches [is] 0.2154 grams and 2.1865 grams, respectively. Uranium mass is measured in batching operations to ensure the U235 mass in the final container is less than 350 grams U235 which is less than half the minimum critical mass at 100% enrichment and optimum moderation, geometry, and reflection conditions."

"NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: Nuclear criticality safety controls include independent mass measurements of U235. Failure to ensure that NCS significant measurements were used lead to a potential failure of the measurements."

"CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEM AND WHEN EACH WAS IMPLEMENTED: A second independent NDA measurement was performed to verity total mass of U235 (<1 gram per bucket/container). Compliance with NCSA-Plant053.A03 was re-established at 1557 hours based on the results of the NDA measurements."

Portsmouth personnel notified the NRC resident inspector and the site Department of Energy manager.