Event Notification Report for January 26, 2000
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
01/25/2000 - 01/26/2000
EVENT NUMBERS
366283663036631366243662536626
General Information or Other
Event Number: 36628
Rep Org: METROPOLITAN DISTRICT
Licensee: METROPOLITAN DISTRICT
Region: 1
City: HARTFORD State: CT
County:
License #:
Agreement: N
Docket:
NRC Notified By: EARL DELANO
HQ OPS Officer: FANGIE JONES
Licensee: METROPOLITAN DISTRICT
Region: 1
City: HARTFORD State: CT
County:
License #:
Agreement: N
Docket:
NRC Notified By: EARL DELANO
HQ OPS Officer: FANGIE JONES
Notification Date: 01/26/2000
Notification Time: 18:23 [ET]
Event Date: 01/26/2000
Event Time: 00:00 [EST]
Last Update Date: 01/26/2000
Notification Time: 18:23 [ET]
Event Date: 01/26/2000
Event Time: 00:00 [EST]
Last Update Date: 01/26/2000
Emergency Class: NON EMERGENCY
10 CFR Section:
10 CFR Section:
Person (Organization):
JOHN ROGGE (R1)
JOHN ROGGE (R1)
REQUIRED REPORT - EXPLOSION IN SHREDDER, NO DAMAGE TO SOURCE IN LEVEL DETECTOR
The operating procedures require notification of the NRC of any explosion in the trash shredders, even if no damage occurs to the source in the level measuring device. It has been determined that small gas welding bottle that contained acetylene caused an explosion in the shredder at Metropolitan District. The source was not damaged. Local authorities were informed and the fire department made the determination of the probable cause.
The operating procedures require notification of the NRC of any explosion in the trash shredders, even if no damage occurs to the source in the level measuring device. It has been determined that small gas welding bottle that contained acetylene caused an explosion in the shredder at Metropolitan District. The source was not damaged. Local authorities were informed and the fire department made the determination of the probable cause.
Power Reactor
Event Number: 36630
Facility: HATCH
Region: 2 State: GA
Unit: [1] [] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: MUSGROVE
HQ OPS Officer: CHAUNCEY GOULD
Region: 2 State: GA
Unit: [1] [] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: MUSGROVE
HQ OPS Officer: CHAUNCEY GOULD
Notification Date: 01/27/2000
Notification Time: 12:09 [ET]
Event Date: 01/26/2000
Event Time: 22:38 [EST]
Last Update Date: 01/27/2000
Notification Time: 12:09 [ET]
Event Date: 01/26/2000
Event Time: 22:38 [EST]
Last Update Date: 01/27/2000
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(ii) - ESF ACTUATION
10 CFR Section:
50.72(b)(2)(ii) - ESF ACTUATION
Person (Organization):
CAUDLE JULIAN (R2)
CAUDLE JULIAN (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Hot Shutdown | 0 | Hot Shutdown |
FAILURE OF PRIMARY CONTAINMENT ISOLATION VALVE TO CLOSE ON A LOW REACTOR PRESSURE SIGNAL.
PRIMARY CONTAINMENT ISOLATION VALVE "1E51-F008" DID NOT CLOSE ON A LOW REACTOR PRESSURE SIGNAL DUE TO INSTRUMENT "1E51-N685C" BEING INOPERABLE. THE OTHER VALVE IN THIS LINE, VALVE "1E51-F007", DID CLOSE TO ISOLATE THE PENETRATION. THE "1E51-F008" VALVE WAS CLOSED AS DIRECTED BY THE SHUTDOWN PROCEDURE "34G0-OPS-013-1S". THIS EVENT IS BEING INVESTIGATED TO DETERMINE THE ROOT CAUSE. THE REPORTABILITY OF THE EVENT WAS NOT DETERMINED AT THE TIME OF THE OCCURRENCE.
THE NRC RESIDENT INSPECTOR WAS NOTIFIED.
[HOO NOTE: SEE RELATED EN 36625.]
PRIMARY CONTAINMENT ISOLATION VALVE "1E51-F008" DID NOT CLOSE ON A LOW REACTOR PRESSURE SIGNAL DUE TO INSTRUMENT "1E51-N685C" BEING INOPERABLE. THE OTHER VALVE IN THIS LINE, VALVE "1E51-F007", DID CLOSE TO ISOLATE THE PENETRATION. THE "1E51-F008" VALVE WAS CLOSED AS DIRECTED BY THE SHUTDOWN PROCEDURE "34G0-OPS-013-1S". THIS EVENT IS BEING INVESTIGATED TO DETERMINE THE ROOT CAUSE. THE REPORTABILITY OF THE EVENT WAS NOT DETERMINED AT THE TIME OF THE OCCURRENCE.
THE NRC RESIDENT INSPECTOR WAS NOTIFIED.
[HOO NOTE: SEE RELATED EN 36625.]
Fuel Cycle Facility
Event Number: 36631
Facility: PORTSMOUTH GASEOUS DIFFUSION PLANT
Region: 3 State: OH
Unit: [] [] []
RX Type: URANIUM ENRICHMENT FACILITY
Comments: 2 DEMOCRACY CENTER
6903 ROCKLEDGE DRIVE
BETHESDA, MD 20817 (301)564-3200
NRC Notified By: MCCLEERY
HQ OPS Officer: CHAUNCEY GOULD
Region: 3 State: OH
Unit: [] [] []
RX Type: URANIUM ENRICHMENT FACILITY
Comments: 2 DEMOCRACY CENTER
6903 ROCKLEDGE DRIVE
BETHESDA, MD 20817 (301)564-3200
NRC Notified By: MCCLEERY
HQ OPS Officer: CHAUNCEY GOULD
Notification Date: 01/27/2000
Notification Time: 14:12 [ET]
Event Date: 01/26/2000
Event Time: 14:45 [EST]
Last Update Date: 01/27/2000
Notification Time: 14:12 [ET]
Event Date: 01/26/2000
Event Time: 14:45 [EST]
Last Update Date: 01/27/2000
Emergency Class: NON EMERGENCY
10 CFR Section:
10 CFR Section:
Person (Organization):
MONTE PHILLIPS (R3)
JOSIE PICCONE (NMSS)
MONTE PHILLIPS (R3)
JOSIE PICCONE (NMSS)
24 HOUR 91-01 BULLETIN RESPONSE
AT APPROXIMATELY 1445 HRS @ 1/26/00, ELEVEN (11) BAGS WITH MISCELLANEOUS CONTENTS WERE DISCOVERED IN THE X-103 HEALTH PHYSICS SOURCE VAULT. THREE (3) OF THE ELEVEN ITEMS CONTAINED GREATER THAN 1% U-235 WITH THE HIGHEST ASSAY BEING 52.1 %. THE TOTAL GRAM CONTENT OF ALL THREE ITEMS INCLUDING ERROR IS 158.5 g U-235 FOR 52% ASSAY (MOST LIMITING). ALL ELEVEN ITEMS WERE PLACED INTO TWO (2) APPROVED CONTAINERS WHICH WERE MOVED TO AN APPROVED STORAGE FACILITY.
THERE WAS NO LOSS OF HAZARDOUS/RADIOACTIVE MATERIAL OR RADIOACTIVE/RADIOLOGICAL CONTAMINATION EXPOSURE AS A RESULT OF THIS EVENT.
THE NRC RESIDENT INSPECTOR WAS NOTIFIED AND THE DOE REPRESENTATIVE WILL BE NOTIFIED
AT APPROXIMATELY 1445 HRS @ 1/26/00, ELEVEN (11) BAGS WITH MISCELLANEOUS CONTENTS WERE DISCOVERED IN THE X-103 HEALTH PHYSICS SOURCE VAULT. THREE (3) OF THE ELEVEN ITEMS CONTAINED GREATER THAN 1% U-235 WITH THE HIGHEST ASSAY BEING 52.1 %. THE TOTAL GRAM CONTENT OF ALL THREE ITEMS INCLUDING ERROR IS 158.5 g U-235 FOR 52% ASSAY (MOST LIMITING). ALL ELEVEN ITEMS WERE PLACED INTO TWO (2) APPROVED CONTAINERS WHICH WERE MOVED TO AN APPROVED STORAGE FACILITY.
THERE WAS NO LOSS OF HAZARDOUS/RADIOACTIVE MATERIAL OR RADIOACTIVE/RADIOLOGICAL CONTAMINATION EXPOSURE AS A RESULT OF THIS EVENT.
THE NRC RESIDENT INSPECTOR WAS NOTIFIED AND THE DOE REPRESENTATIVE WILL BE NOTIFIED
Power Reactor
Event Number: 36624
Facility: SEQUOYAH
Region: 2 State: TN
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: JEFF EPPERSON
HQ OPS Officer: JOHN MacKINNON
Region: 2 State: TN
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: JEFF EPPERSON
HQ OPS Officer: JOHN MacKINNON
Notification Date: 01/26/2000
Notification Time: 04:29 [ET]
Event Date: 01/26/2000
Event Time: 00:39 [EST]
Last Update Date: 01/26/2000
Notification Time: 04:29 [ET]
Event Date: 01/26/2000
Event Time: 00:39 [EST]
Last Update Date: 01/26/2000
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iii)(D) - ACCIDENT MITIGATION
10 CFR Section:
50.72(b)(2)(iii)(D) - ACCIDENT MITIGATION
Person (Organization):
CAUDLE JULIAN (R2)
CAUDLE JULIAN (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
UNIT 2 ENTERED TECH SPEC 3.0.3 DUE TO BOTH TRAINS SAFETY INJECTION INOPERABLE
"AT 0039 EST ON 1/26/2000 BOTH TRAINS OF THE SAFETY INJECTION PUMPS (SIPs) OF SEQUOYAH UNIT 2 WERE RENDERED INOPERABLE. THE '2A' SAFETY INJECTION PUMP AND ITS ROOM COOLER WERE TAGGED OUT UNDER THE SITES TAGOUT PROCEDURE FOR MAINTENANCE. EITHER OF THESE COMPONENTS [SI PUMP OR ITS ASSOCIATED ROOM COOLER] BEING TAGGED MADE THE PUMP INOPERABLE. WHILE THE '2A' SI PUMP WAS INOPERABLE, MAINTENANCE WORKERS MISTAKENLY DRAINED THE OIL FROM THE '2B' SAFETY INJECTION PUMP MOTOR BEARING FOR A PERIOD OF TIME WHICH MADE IT INOPERABLE AND UNAVAILABLE. THIS OIL CHANGING EVOLUTION REQUIRED APPROXIMATELY 30 MINUTES TO ACCOMPLISH. THE SIMULANTEOUS INOPERABILITY OF BOTH UNIT 2 SI PUMPS REQUIRED ENTRY INTO TECHNICAL SPECIFICATION LCO 3.0.3 ACTION. IMMEDIATE STEPS WERE INITIATED TO RESTORE OPERABILITY TO '2B' SI PUMP. AT 0316 EST ON 1/26/2000 THE '2B' SI PUMP WAS DECLARED OPERABLE WHEN THE PUMP WAS SUCCESSFULLY RUN. LCO 3.0.3 ACTION WAS THEN EXITED. AN INVESTIGATION INTO THE CAUSE OF THIS EVENT WILL BE CONDUCTED."
MAINTENANCE WORKERS WERE TAKING A SAMPLE OF THE BEARING OIL FOR ANALYSIS WHICH IS USUALLY ACCOMPLISHED THROUGH DRAINING.
THE NRC RESIDENT INSPECTOR WILL BE INFORMED.
"AT 0039 EST ON 1/26/2000 BOTH TRAINS OF THE SAFETY INJECTION PUMPS (SIPs) OF SEQUOYAH UNIT 2 WERE RENDERED INOPERABLE. THE '2A' SAFETY INJECTION PUMP AND ITS ROOM COOLER WERE TAGGED OUT UNDER THE SITES TAGOUT PROCEDURE FOR MAINTENANCE. EITHER OF THESE COMPONENTS [SI PUMP OR ITS ASSOCIATED ROOM COOLER] BEING TAGGED MADE THE PUMP INOPERABLE. WHILE THE '2A' SI PUMP WAS INOPERABLE, MAINTENANCE WORKERS MISTAKENLY DRAINED THE OIL FROM THE '2B' SAFETY INJECTION PUMP MOTOR BEARING FOR A PERIOD OF TIME WHICH MADE IT INOPERABLE AND UNAVAILABLE. THIS OIL CHANGING EVOLUTION REQUIRED APPROXIMATELY 30 MINUTES TO ACCOMPLISH. THE SIMULANTEOUS INOPERABILITY OF BOTH UNIT 2 SI PUMPS REQUIRED ENTRY INTO TECHNICAL SPECIFICATION LCO 3.0.3 ACTION. IMMEDIATE STEPS WERE INITIATED TO RESTORE OPERABILITY TO '2B' SI PUMP. AT 0316 EST ON 1/26/2000 THE '2B' SI PUMP WAS DECLARED OPERABLE WHEN THE PUMP WAS SUCCESSFULLY RUN. LCO 3.0.3 ACTION WAS THEN EXITED. AN INVESTIGATION INTO THE CAUSE OF THIS EVENT WILL BE CONDUCTED."
MAINTENANCE WORKERS WERE TAKING A SAMPLE OF THE BEARING OIL FOR ANALYSIS WHICH IS USUALLY ACCOMPLISHED THROUGH DRAINING.
THE NRC RESIDENT INSPECTOR WILL BE INFORMED.
Power Reactor
Event Number: 36625
Facility: HATCH
Region: 2 State: GA
Unit: [1] [] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: FRANK GORLEY
HQ OPS Officer: STEVE SANDIN
Region: 2 State: GA
Unit: [1] [] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: FRANK GORLEY
HQ OPS Officer: STEVE SANDIN
Notification Date: 01/26/2000
Notification Time: 07:42 [ET]
Event Date: 01/26/2000
Event Time: 06:48 [EST]
Last Update Date: 01/30/2000
Notification Time: 07:42 [ET]
Event Date: 01/26/2000
Event Time: 06:48 [EST]
Last Update Date: 01/30/2000
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(1)(iv) - ECCS INJECTION 50.72(b)(2)(ii) - ESF ACTUATION
10 CFR Section:
50.72(b)(1)(iv) - ECCS INJECTION 50.72(b)(2)(ii) - ESF ACTUATION
Person (Organization):
CAUDLE JULIAN (R2)
WILLIAM BATEMAN (NRR)
FRANK CONGEL (IRO)
CAUDLE JULIAN (R2)
WILLIAM BATEMAN (NRR)
FRANK CONGEL (IRO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | A/R | Y | 100 | Power Operation | 0 | Hot Shutdown |
UNIT 1 EXPERIENCED AN AUTOMATIC REACTOR SCRAM ON LOW REACTOR VESSEL WATER LEVEL DUE TO A FEEDWATER (FW) CONTROL FAILURE.
AT APPROXIMATELY 0648 EST ON 1/26/2000, CONTROL ROOM OPERATORS RESPONDED TO A FEEDWATER CONTROL FAILURE ALARM. WHILE INVESTIGATING, FEEDWATER PUMP SPEED DECREASED CAUSING REACTOR VESSEL WATER LEVEL (RVWL) TO DROP FROM ITS NORMAL OPERATING LEVEL OF 37.5" TO APPROXIMATELY -45". AT 0", AN AUTOMATIC REACTOR SCRAM AND GROUP 2 ENGINEERED SAFEGUARDS FEATURES (ESF) ACTUATION OCCURRED, AS EXPECTED. ALL CONTROL RODS FULLY INSERTED. AT -38", BOTH THE HIGH PRESSURE COOLANT INJECTION (HPCI) AND REACTOR CORE ISOLATION COOLING (RCIC) SYSTEM RECEIVED A START SIGNAL. HPCI INJECTED UNTIL THE HPCI PUMP TRIPPED AT ITS RVWL SETPOINT OF 51.5". THE FW PUMPS TRIPPED AT 58" WITH RVWL SWELL CAUSING LEVEL TO REACH 100". FOLLOWING THE LEVEL TRANSIENT, OPERATORS HAD DIFFICULTY IN ESTABLISHING THE LOW-LOW SET RANGE FOR PRESSURE CONTROL. NORMALLY, ONE OF THE FOUR SAFETY RELIEF VALVES (SRV) USED FOR PRESSURE CONTROL (i.e., THE "H," "A," "G," OR "C" SRV) IS OPENED ELECTRICALLY FROM THE CONTROL ROOM WHICH THEN ESTABLISHES THE LOWER PRESSURE CONTROL. TEN OF THE ELEVEN SRVs FAILED TO OPEN IN RESPONSE TO CONTROL ROOM SWITCH POSITIONING. THE LAST SRV ATTEMPTED (THE "B" SRV) OPENED. UNIT 1 IS CURRENTLY STABLE IN HOT SHUTDOWN REJECTING DECAY HEAT TO THE TORUS WITH BOTH TRAINS OF SUPPRESSION POOL COOLING IN SERVICE. EFFORTS ARE UNDERWAY TO RESTORE THE MAIN CONDENSER AS A HEAT SINK. THE LICENSEE INTENDS TO COOL DOWN UNIT 1 TO INVESTIGATE AND RESOLVE THE PROBLEM WITH THE SRVs. THERE IS NO INDICATION THAT THE SRV MECHANICAL SAFETY OR AUTOMATIC DEPRESSURIZATION SYSTEM FUNCTION IS IMPAIRED AT THIS TIME. DURING THE TRANSIENT, REACTOR COOLANT SYSTEM (RCS) TEMPERATURE AND PRESSURE DECREASED FROM THEIR NORMAL AT POWER VALUES OF 532°F AND 1035 PSIG TO AN OBSERVED MINIMUM OF 480°F AND 871 PSIG. BOTH ARE CURRENTLY AT 510°F AND 977 PSIG. THERE IS NO INDICATION THAT THE 100°F/HOUR COOLDOWN RATE WAS EXCEEDED.
THE LICENSEE INFORMED THE NRC RESIDENT INSPECTOR.
******************* UPDATE AT 0138 ON 01/30/00 FROM BRUCE BUTLER TO LEIGH TROCINE *******************
The following text is a portion of a facsimile received from the licensee:
"Upon subsequent investigation, the event review team determined that the cause of the low level condition that resulted in the Unit 1 reactor scram was the inadvertent closure of feedwater valve 1N21-F005B. This valve is the inlet valve to the 5th-stage feedwater heater. Closure of the valve caused a feedwater flow reduction such that the low level scram setpoint was reached. The valve closure was apparently caused by the spurious contact closure within the control switch for the valve."
"The plant systems initially appeared to respond automatically as expected to this transient condition. Even though the [HPCI] system appeared initially to trip at its high level setpoint, subsequent review of its operation revealed that it operated longer than expected, and reactor water reached a higher level than desired. Operators isolated the main steam isolation valves [(MSIV)] in accordance with plant procedures. The HPCI system eventually tripped, and reactor water level appeared to stop increasing before reaching the main steam lines. A more detailed review of the event using the plant's safety parameter display system (SPDS) revealed that reactor water level increased to the point that water apparently reached the bottom of the main steam lines with some water entering the lines."
"Operators proceeded to control reactor pressure using the main [SRV] system manually and in the low-low set mode of operation. Normally one (1) of the four (4) SRVs used for pressure control is opened manually from the main control room, which then initiates automatic pressure control using the SRVs in the low-low set mode. An operator attempted to manually open nine (9) of the eleven (11) SRVs but did not receive direct indication that any of these SRVs opened. When a tenth SRV was opened, the operator received direct indication that the SRV opened."
"During subsequent investigation, the event review team has preliminarily determined that apparently enough water entered the main steam lines to flood the SRVs. With the MSIVs closed, engineers calculated that a total of approximately 4,100 gallons of water would be necessary to flood the SRVs. The amount of water necessary to flood the SRVs differs with each steam line, but it would only require an entry of approximately 860 to 1,060 gallons to flood the affected SRVs. A review of the data indicated that the flooded SRVs, although flooded, apparently opened upon demand by the operator. This is based upon a significant and rapid increase in the tailpipe temperature for the SRVs that were given an 'open' signal. Since the medium passing through the SRV was two-phase, the tailpipe pressure switches that provide positive direct indication that the SRV opened, and initiate the low-low set logic, did not actuate on nine of the SRVs. This led the operator to believe that those SRVs had not opened. When the operator gave the 'B' SRV an 'open' signal, enough of the water had been displaced to allow the tailpipe pressure switch to react normally. This resulted in the operator seeing direct indication that the 'B' SRV opened and actuation of low-low set logic. The operation of the SRVs with a two-phase medium was confirmed by an engineer from General Electric with extensive experience in SRV design and operation."
"The plant is currently in Cold Shutdown. As a conservative measure all eleven SRV topworks and solenoids were removed and replaced. Initially, five (5) topworks and four (4) solenoids were sent to Wyle labs. Preliminary results of testing performed at Wyle labs indicated [that] these five topworks and four solenoids functioned normally. The remainder of the solenoids is being checked by Target Rock technicians at the plant. Appropriate walkdowns of plant systems are being conducted, and followup is occurring for equipment items that require resolution prior to startup."
"Plant management [plans to] review and evaluate the event in its entirety and the response of plant systems before granting permission for restart of the unit."
The licensee notified the NRC resident inspector. The NRC operation officer notified the R2DO (Julian), NRR EO (Matthews), and IRO (Congel.)
AT APPROXIMATELY 0648 EST ON 1/26/2000, CONTROL ROOM OPERATORS RESPONDED TO A FEEDWATER CONTROL FAILURE ALARM. WHILE INVESTIGATING, FEEDWATER PUMP SPEED DECREASED CAUSING REACTOR VESSEL WATER LEVEL (RVWL) TO DROP FROM ITS NORMAL OPERATING LEVEL OF 37.5" TO APPROXIMATELY -45". AT 0", AN AUTOMATIC REACTOR SCRAM AND GROUP 2 ENGINEERED SAFEGUARDS FEATURES (ESF) ACTUATION OCCURRED, AS EXPECTED. ALL CONTROL RODS FULLY INSERTED. AT -38", BOTH THE HIGH PRESSURE COOLANT INJECTION (HPCI) AND REACTOR CORE ISOLATION COOLING (RCIC) SYSTEM RECEIVED A START SIGNAL. HPCI INJECTED UNTIL THE HPCI PUMP TRIPPED AT ITS RVWL SETPOINT OF 51.5". THE FW PUMPS TRIPPED AT 58" WITH RVWL SWELL CAUSING LEVEL TO REACH 100". FOLLOWING THE LEVEL TRANSIENT, OPERATORS HAD DIFFICULTY IN ESTABLISHING THE LOW-LOW SET RANGE FOR PRESSURE CONTROL. NORMALLY, ONE OF THE FOUR SAFETY RELIEF VALVES (SRV) USED FOR PRESSURE CONTROL (i.e., THE "H," "A," "G," OR "C" SRV) IS OPENED ELECTRICALLY FROM THE CONTROL ROOM WHICH THEN ESTABLISHES THE LOWER PRESSURE CONTROL. TEN OF THE ELEVEN SRVs FAILED TO OPEN IN RESPONSE TO CONTROL ROOM SWITCH POSITIONING. THE LAST SRV ATTEMPTED (THE "B" SRV) OPENED. UNIT 1 IS CURRENTLY STABLE IN HOT SHUTDOWN REJECTING DECAY HEAT TO THE TORUS WITH BOTH TRAINS OF SUPPRESSION POOL COOLING IN SERVICE. EFFORTS ARE UNDERWAY TO RESTORE THE MAIN CONDENSER AS A HEAT SINK. THE LICENSEE INTENDS TO COOL DOWN UNIT 1 TO INVESTIGATE AND RESOLVE THE PROBLEM WITH THE SRVs. THERE IS NO INDICATION THAT THE SRV MECHANICAL SAFETY OR AUTOMATIC DEPRESSURIZATION SYSTEM FUNCTION IS IMPAIRED AT THIS TIME. DURING THE TRANSIENT, REACTOR COOLANT SYSTEM (RCS) TEMPERATURE AND PRESSURE DECREASED FROM THEIR NORMAL AT POWER VALUES OF 532°F AND 1035 PSIG TO AN OBSERVED MINIMUM OF 480°F AND 871 PSIG. BOTH ARE CURRENTLY AT 510°F AND 977 PSIG. THERE IS NO INDICATION THAT THE 100°F/HOUR COOLDOWN RATE WAS EXCEEDED.
THE LICENSEE INFORMED THE NRC RESIDENT INSPECTOR.
******************* UPDATE AT 0138 ON 01/30/00 FROM BRUCE BUTLER TO LEIGH TROCINE *******************
The following text is a portion of a facsimile received from the licensee:
"Upon subsequent investigation, the event review team determined that the cause of the low level condition that resulted in the Unit 1 reactor scram was the inadvertent closure of feedwater valve 1N21-F005B. This valve is the inlet valve to the 5th-stage feedwater heater. Closure of the valve caused a feedwater flow reduction such that the low level scram setpoint was reached. The valve closure was apparently caused by the spurious contact closure within the control switch for the valve."
"The plant systems initially appeared to respond automatically as expected to this transient condition. Even though the [HPCI] system appeared initially to trip at its high level setpoint, subsequent review of its operation revealed that it operated longer than expected, and reactor water reached a higher level than desired. Operators isolated the main steam isolation valves [(MSIV)] in accordance with plant procedures. The HPCI system eventually tripped, and reactor water level appeared to stop increasing before reaching the main steam lines. A more detailed review of the event using the plant's safety parameter display system (SPDS) revealed that reactor water level increased to the point that water apparently reached the bottom of the main steam lines with some water entering the lines."
"Operators proceeded to control reactor pressure using the main [SRV] system manually and in the low-low set mode of operation. Normally one (1) of the four (4) SRVs used for pressure control is opened manually from the main control room, which then initiates automatic pressure control using the SRVs in the low-low set mode. An operator attempted to manually open nine (9) of the eleven (11) SRVs but did not receive direct indication that any of these SRVs opened. When a tenth SRV was opened, the operator received direct indication that the SRV opened."
"During subsequent investigation, the event review team has preliminarily determined that apparently enough water entered the main steam lines to flood the SRVs. With the MSIVs closed, engineers calculated that a total of approximately 4,100 gallons of water would be necessary to flood the SRVs. The amount of water necessary to flood the SRVs differs with each steam line, but it would only require an entry of approximately 860 to 1,060 gallons to flood the affected SRVs. A review of the data indicated that the flooded SRVs, although flooded, apparently opened upon demand by the operator. This is based upon a significant and rapid increase in the tailpipe temperature for the SRVs that were given an 'open' signal. Since the medium passing through the SRV was two-phase, the tailpipe pressure switches that provide positive direct indication that the SRV opened, and initiate the low-low set logic, did not actuate on nine of the SRVs. This led the operator to believe that those SRVs had not opened. When the operator gave the 'B' SRV an 'open' signal, enough of the water had been displaced to allow the tailpipe pressure switch to react normally. This resulted in the operator seeing direct indication that the 'B' SRV opened and actuation of low-low set logic. The operation of the SRVs with a two-phase medium was confirmed by an engineer from General Electric with extensive experience in SRV design and operation."
"The plant is currently in Cold Shutdown. As a conservative measure all eleven SRV topworks and solenoids were removed and replaced. Initially, five (5) topworks and four (4) solenoids were sent to Wyle labs. Preliminary results of testing performed at Wyle labs indicated [that] these five topworks and four solenoids functioned normally. The remainder of the solenoids is being checked by Target Rock technicians at the plant. Appropriate walkdowns of plant systems are being conducted, and followup is occurring for equipment items that require resolution prior to startup."
"Plant management [plans to] review and evaluate the event in its entirety and the response of plant systems before granting permission for restart of the unit."
The licensee notified the NRC resident inspector. The NRC operation officer notified the R2DO (Julian), NRR EO (Matthews), and IRO (Congel.)
Power Reactor
Event Number: 36626
Facility: MILLSTONE
Region: 1 State: CT
Unit: [1] [2] [3]
RX Type: [1] GE-3,[2] CE,[3] W-4-LP
NRC Notified By: STEVE LAWHEAD
HQ OPS Officer: STEVE SANDIN
Region: 1 State: CT
Unit: [1] [2] [3]
RX Type: [1] GE-3,[2] CE,[3] W-4-LP
NRC Notified By: STEVE LAWHEAD
HQ OPS Officer: STEVE SANDIN
Notification Date: 01/26/2000
Notification Time: 11:06 [ET]
Event Date: 01/26/2000
Event Time: 09:47 [EST]
Last Update Date: 01/26/2000
Notification Time: 11:06 [ET]
Event Date: 01/26/2000
Event Time: 09:47 [EST]
Last Update Date: 01/26/2000
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(vi) - OFFSITE NOTIFICATION
10 CFR Section:
50.72(b)(2)(vi) - OFFSITE NOTIFICATION
Person (Organization):
JOHN ROGGE (R1)
WILLIAM BATEMAN (NRR)
FRANK CONGEL (IRO)
JOHN ROGGE (R1)
WILLIAM BATEMAN (NRR)
FRANK CONGEL (IRO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Refueling | 0 | Refueling |
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
| 3 | N | Y | 100 | Power Operation | 100 | Power Operation |
OFFSITE NOTIFICATION TO STATE/LOCAL AGENCIES INVOLVING ERRONEOUS EMERGENCY
"At 0947 on January 26, 2000 a notification to offsite emergency response agencies was made in error. The notification indicated that a General Emergency had been declared at Millstone. No emergency conditions currently exists at the site. The notification occurred during testing of the primary notification system. The cause of the condition is being investigated at this time. Backup means of notification is available in the event that a bonafide emergency condition arises prior to the restoration of the primary notification system.
"Retractions of the event notification were issued to appropriate State and local agencies. Millstone emergency management personnel have also been in contact with representatives of these agencies."
The licensee informed the NRC Resident Inspector.
"At 0947 on January 26, 2000 a notification to offsite emergency response agencies was made in error. The notification indicated that a General Emergency had been declared at Millstone. No emergency conditions currently exists at the site. The notification occurred during testing of the primary notification system. The cause of the condition is being investigated at this time. Backup means of notification is available in the event that a bonafide emergency condition arises prior to the restoration of the primary notification system.
"Retractions of the event notification were issued to appropriate State and local agencies. Millstone emergency management personnel have also been in contact with representatives of these agencies."
The licensee informed the NRC Resident Inspector.