U.S. Nuclear Regulatory Commission Operations Center Event Reports For 12/24/1998 - 12/28/1998 ** EVENT NUMBERS ** 35191 35192 35193 35194 35195 35196 35197 35198 +------------------------------------------------------------------------------+ |Power Reactor |Event Number: 35191 | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ | FACILITY: BROWNS FERRY REGION: 2 |NOTIFICATION DATE: 12/24/1998| | UNIT: [1] [2] [3] STATE: AL |NOTIFICATION TIME: 11:52[EST]| | RXTYPE: [1] GE-4,[2] GE-4,[3] GE-4 |EVENT DATE: 12/24/1998| +------------------------------------------------+EVENT TIME: 10:05[CST]| | NRC NOTIFIED BY: RONALD DAVENPORT |LAST UPDATE DATE: 12/25/1998| | HQ OPS OFFICER: STEVE SANDIN +-----------------------------+ +------------------------------------------------+PERSON ORGANIZATION | |EMERGENCY CLASS: N/A |PIERCE SKINNER R2 | |10 CFR SECTION: | | |AESS 50.72(b)(1)(v) EMERGENCY SIREN INOP | | | | | | | | | | | +-----+----------+-------+--------+-----------------+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR 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 | +------------------------------------------------------------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | LOSS OF POWER TO HALF OF THE OFFSITE EMERGENCY NOTIFICATION SIRENS DUE TO AN | | ICE STORM AND POWER OUTAGE | | | | The following text is a portion of a facsimile received from the licensee: | | | | "The number of operable offsite emergency notification sirens [is] below the | | minimum required for emergency preparedness within the 10-mile emergency | | preparedness zone (EPZ). The total number of sirens is one hundred (100), | | the minimum required is seventy (70), and the number of operable sirens [is] | | fifty (50) at this time. The ice storm affecting the Browns Ferry area is | | causing the failures due to loss of power to the sirens. The county | | agencies are trying to determine when power will be restored at this time. | | Further failures of sirens may result as the ice storm continues." | | | | "This event is reportable per 10CFR50.72(b)(1 )(v) as any event that results | | in a major loss of emergency assessment capability, offsite response | | capability, or communications capability (e.g., significant portion of | | control room indication, emergency notification system, or offsite | | notification system)." | | | | The licensee notified the State and plans to notify the NRC resident | | inspector. | | | | *************** UPDATE AT 1903 ON 12/25/98 FROM MIKE MORROW TO LEIGH TROCINE | | *************** | | | | Power has been restored to a large portion of the county, and 80 of 100 | | offsite emergency notification sirens are currently operable. The minimum | | number of operable offsite emergency notification sirens (70) was attained | | at approximately 0800 CST. The licensee expects to have power restored to | | the remainder of the offsite emergency notification sirens within the next | | day or so. | | | | The licensee plans to notify the NRC resident inspector. The NRC Operations | | Officer notified the R2DO (Skinner). | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ |Power Reactor |Event Number: 35192 | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ | FACILITY: ARKANSAS NUCLEAR REGION: 4 |NOTIFICATION DATE: 12/25/1998| | UNIT: [1] [] [] STATE: AR |NOTIFICATION TIME: 12:11[EST]| | RXTYPE: [1] B&W-L-LP,[2] CE |EVENT DATE: 12/25/1998| +------------------------------------------------+EVENT TIME: 08:51[CST]| | NRC NOTIFIED BY: REX KNIGHT |LAST UPDATE DATE: 12/25/1998| | HQ OPS OFFICER: LEIGH TROCINE +-----------------------------+ +------------------------------------------------+PERSON ORGANIZATION | |EMERGENCY CLASS: N/A |BLAIR SPITZBERG R4 | |10 CFR SECTION: |RICHARD WESSMAN, EO NRR | |ARPS 50.72(b)(2)(ii) RPS ACTUATION | | |AESF 50.72(b)(2)(ii) ESF ACTUATION | | |APRE 50.72(b)(2)(vi) OFFSITE NOTIFICATION | | | | | +-----+----------+-------+--------+-----------------+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ |1 M/R Y 75 Power Operation |0 Hot Shutdown | | | | | | | +------------------------------------------------------------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | MANUAL REACTOR TRIP FROM 75% POWER DUE TO SHAD BLOCKING THE INTAKE STRUCTURE | | SCREENS AND THE SUBSEQUENT LOSS OF ALL CIRCULATING WATER PUMPS | | | | The unit was at 100% reactor power when a shad run occurred at the intake | | structure. The licensee began to manually decrease Unit 1 reactor power at | | approximately 0849 CST due to the increase in intake screen differential | | pressure. All four circulating water pumps were manually secured, and the | | reactor was manually tripped from 75% power at 0851 CST. All rods fully | | inserted. The emergency feedwater system was manually actuated. There | | were no emergency core cooling system actuations. | | | | Condenser vacuum was degraded but never lost during this transient. It went | | from a normal value of 27 inches of mercury absolute to 23-24 inches of | | mercury absolute. Condenser vacuum has since been restored to normal | | because two of the four circulating water pumps have been returned to | | service. | | | | During this event, some of the main steam safety valves lifted to relieve | | secondary steam to atmosphere. All of these valves reseated. However, one | | main steam safety valve on each steam generator seated at a lower than | | normal pressure. The licensee stated that there was not a large blowdown | | and that there was not a large reactor coolant system cooldown as a result | | of this. There were no indications of abnormal steam radiation. | | | | In addition, the 'B' startup control valve failed at approximately 50% open. | | This valve is a non-safety-related valve associated with the normal | | feedwater system. Emergency feedwater was already running when the 'B' | | startup control valve was isolated, and emergency feedwater properly | | maintained steam generator water levels. | | | | The reactor is currently stable. Reactor coolant system inventory, | | pressure, and transport control are being maintained via normal charging and | | letdown, pressurizer heaters and sprays, and the reactor coolant pumps. The | | condenser is being used as a heat sink, and both emergency feedwater (safety | | related) and auxiliary feedwater (non-safety related) are being used to | | supply water to the steam generators. The licensee stated that there is an | | ongoing steam release because the steam-driven emergency feedwater pump is | | in service. However, there are no current indications of abnormal steam | | radiation. Containment parameters are normal. Offsite power is available, | | and the emergency diesel generators are operable if needed. | | | | Although both units share a common intake, Unit 2 was not affected by this | | event, and it has remained operating at 100% power. The licensee stated | | that the shad were more concentrated on the Unit 1 side of the intake | | screens and that Unit 2 requires less circulating water flow than Unit 1 | | because Unit 2 has a cooling tower. | | | | The licensee notified the State and the NRC resident inspector. | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ |Fuel Cycle Facility |Event Number: 35193 | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ | FACILITY: PORTSMOUTH GASEOUS DIFFUSION PLANT |NOTIFICATION DATE: 12/25/1998| | RXTYPE: URANIUM ENRICHMENT FACILITY |NOTIFICATION TIME: 13:05[EST]| | COMMENTS: 2 DEMOCRACY CENTER |EVENT DATE: 12/25/1998| | 6903 ROCKLEDGE DRIVE |EVENT TIME: 10:28[EST]| | BETHESDA, MD 20817 (301)564-3200 |LAST UPDATE DATE: 12/25/1998| | CITY: PIKETON REGION: 3 +-----------------------------+ | COUNTY: PIKE STATE: OH |PERSON ORGANIZATION | |LICENSE#: GDP-2 AGREEMENT: N |JOHN MADERA R3 | | DOCKET: 0707002 |FREDERICK COMBS, EO NMSS | +------------------------------------------------+STUART RUBIN, AEOD IRD | | NRC NOTIFIED BY: KEITH VANDERPOOL | | | HQ OPS OFFICER: LEIGH TROCINE | | +------------------------------------------------+ | |EMERGENCY CLASS: N/A | | |10 CFR SECTION: | | |NCFR NON CFR REPORT REQMNT | | | | | | | | | | | | | | +------------------------------------------------------------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | OFFSITE NOTIFICATION OF EXCEEDANCE OF THE STATE'S OPACITY LIMIT DUE TO | | PROBLEMS WITH THREE X-600 STEAM PLANT BOILERS (4-HOUR NOTIFICATION) | | | | The following text is a portion of a facsimile received from Portsmouth: | | | | ". . . USEC event reporting procedure UE2-MC-RE1030, Appendix 'D,' Section | | 'P,' requires USEC to notify [the] NRC of any event or situation related to | | the protection of the environment for which notification to other government | | agencies has been made." | | | | "On December 25, 1998, at 0450 hours, power was lost to the #1 boiler | | causing a water fluctuation to the #2 and #3 boilers. [The #1 boiler was | | subsequently placed back on line.] At 0512 hours, [the] #2 boiler tripped | | off; at 0518 hours, the #3 boiler tripped off; and at 0550 hours the #1 | | boiler tripped off. [These three X-600 steam plant boilers generate steam | | for the entire plant. Subsequent investigations revealed a bad motor (went | | to ground) on a high pressure blower associated with the #1 boiler.]" | | | | "At 1025 hours, it was determined that an opacity exceedance (85%) occurred | | between the hours of 0455 and 0537 thus requiring a necessity to notify the | | Ohio Environmental Protection Agency. The need for this offsite contact of | | another government agency prompts [an] NRC 4-hour notification event. The | | [Ohio Environmental Protection Agency] opacity limit is 20%. [Opacity is an | | air quality limit.]" | | | | "There was no release of hazardous/radioactive materials or | | radioactive/radiological contamination exposure as a result of this event." | | | | Portsmouth personnel notified the NRC resident inspector, Department of | | Energy onsite representative, and Ohio Environmental Protection Agency. | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ |Power Reactor |Event Number: 35194 | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ | FACILITY: MILLSTONE REGION: 1 |NOTIFICATION DATE: 12/26/1998| | UNIT: [] [] [3] STATE: CT |NOTIFICATION TIME: 19:10[EST]| | RXTYPE: [1] GE-3,[2] CE,[3] W-4-LP |EVENT DATE: 12/26/1998| +------------------------------------------------+EVENT TIME: 18:39[EST]| | NRC NOTIFIED BY: STEVE LAWHEAD |LAST UPDATE DATE: 12/26/1998| | HQ OPS OFFICER: LEIGH TROCINE +-----------------------------+ +------------------------------------------------+PERSON ORGANIZATION | |EMERGENCY CLASS: N/A |JOHN WHITE R1 | |10 CFR SECTION: | | |ARPS 50.72(b)(2)(ii) RPS ACTUATION | | |AESF 50.72(b)(2)(ii) ESF ACTUATION | | | | | | | | +-----+----------+-------+--------+-----------------+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | | | | | | |3 M/R N 0 Hot Standby |0 Hot Standby | +------------------------------------------------------------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | MANUAL REACTOR TRIP FROM MODE 3 DUE TO A PROBLEM WITH THE ROD CONTROL | | SYSTEM | | | | At the time of this event, the unit was in Mode 3 with the shutdown banks | | withdrawn in preparation for startup. The startup was delayed due to a | | problem with an intermediate range nuclear instrument, and the licensee | | planned to manually insert the shutdown banks and open the trip breakers in | | order to perform troubleshooting activities. When the licensee attempted to | | manually insert the shutdown banks, one of the shutdown banks did not move. | | As a result, the licensee manually tripped the reactor from Mode 3 at 1839 | | on 12/26/98. All rods fully inserted. A feedwater isolation also occurred, | | but there was no affect on the plant because main feedwater was not in | | service at the time of the event. Auxiliary feedwater was in service at the | | time, and it remained in service. | | | | The unit is currently stable in Mode 3. Primary inventory, pressure, and | | transport control are being maintained by use of normal charging and | | makeup, pressurizer heaters and sprays, and the reactor coolant pumps. | | Auxiliary feedwater is supplying water to the steam generators, and the | | condenser is available as a heat sink. | | | | The licensee notified the NRC resident inspector and applicable state and | | local agencies. | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ |Power Reactor |Event Number: 35195 | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ | FACILITY: HARRIS REGION: 2 |NOTIFICATION DATE: 12/27/1998| | UNIT: [1] [] [] STATE: NC |NOTIFICATION TIME: 11:05[EST]| | RXTYPE: [1] W-3-LP |EVENT DATE: 12/24/1998| +------------------------------------------------+EVENT TIME: 06:37[EST]| | NRC NOTIFIED BY: ANDY BARBEE |LAST UPDATE DATE: 12/27/1998| | HQ OPS OFFICER: DOUG WEAVER +-----------------------------+ +------------------------------------------------+PERSON ORGANIZATION | |EMERGENCY CLASS: N/A |PIERCE SKINNER R2 | |10 CFR SECTION: | | |AESS 50.72(b)(1)(v) EMERGENCY SIREN INOP | | | | | | | | | | | +-----+----------+-------+--------+-----------------+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ |1 N Y 100 Power Operation |100 Power Operation | | | | | | | +------------------------------------------------------------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | WINTER STORM DISABLES EMERGENCY WARNING SIRENS | | | | The following text is a portion of a facsimile received from the licensee: | | | | "As of 06:37 on 12/24/98, a winter weather ice storm resulted in loss of | | electrical power to greater than 20% of the warning sirens within the | | emergency planning zone around the Harris Plant. The plant defines a major | | loss of off site warning capability per 10CFR50.72(b)(1)(v) as a loss of | | greater than or equal to 20% of the sirens. The Harris Plant warning system | | is comprised of 81 warning sirens. As of 06:37 on 12/24/98, the limit was | | exceeded in that the electrical distribution monitoring system detected a | | loss of power to feeder lines/transformers that provide electrical power to | | 18 of the plant's warning sirens. The power outages continued through the | | day with the siren system being restored to greater than the reportability | | threshold as of 22:44 on 12/24/98. The maximum number of sirens out of | | service during the period of the electrical outages was 31 sirens (as of | | 12:41)." | | | | "The Harris plant does not have a direct siren monitoring and feedback | | system. Monitoring of siren capability is accomplished via monitoring of | | electrical power availability. The communication to the main control room | | associated with the detection of this condition did not occur until 10:15 on | | 12/27/98." | | | | "The cause of the delay in notifying the main control room of the siren | | outage status is currently being assessed." | | | | The licensee plans to inform the NRC resident inspector. | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ |Power Reactor |Event Number: 35196 | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ | FACILITY: PEACH BOTTOM REGION: 1 |NOTIFICATION DATE: 12/27/1998| | UNIT: [2] [3] [] STATE: PA |NOTIFICATION TIME: 12:31[EST]| | RXTYPE: [2] GE-4,[3] GE-4 |EVENT DATE: 12/27/1998| +------------------------------------------------+EVENT TIME: 09:21[EST]| | NRC NOTIFIED BY: RICHARD STOTT |LAST UPDATE DATE: 12/27/1998| | HQ OPS OFFICER: LEIGH TROCINE +-----------------------------+ +------------------------------------------------+PERSON ORGANIZATION | |EMERGENCY CLASS: N/A |JOHN WHITE R1 | |10 CFR SECTION: | | |AESF 50.72(b)(2)(ii) ESF ACTUATION | | |NLCO TECH SPEC LCO A/S | | | | | | | | +-----+----------+-------+--------+-----------------+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ |2 N Y 100 Power Operation |100 Power Operation | |3 N Y 100 Power Operation |100 Power Operation | | | | +------------------------------------------------------------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | ENGINEERED SAFETY FEATURE ACTUATIONS DUE TO THE UNEXPECTED OPENING OF A | | BREAKER AND SUBSEQUENT SWAP OF 4-kV BUSES TO THEIR ALTERNATE FEEDS | | | | The following text is a portion of a facsimile received from the licensee: | | | | "With both units at 100% power, the 2SU-E breaker (252-0310) opened | | unexpectedly. This [breaker] feeds [half of] the Unit 2 [and 3] 4-kV | | emergency buses [(E-12, E-23, E-32, and E-43), and] the [breakers for these | | buses (E-212, E-323, E-232, and E-343, respectively) opened]. When the | | 2SU-E breaker opened, all [of the affected] 4-kV buses swapped to their | | alternate feeds successfully maintaining power to all 4-kV buses." | | | | "Due to the 4-kV bus swaps, the following systems were affected on Unit 2: | | Reactor water cleanup [(RWCU)] isolated due to the loss of station 20Y35 bus | | power. Loss of this power cause[d] the control logic for RWCU to | | de-energize momentarily and isolate the RWCU system. This isolation ha[d] | | no effect on power level of Unit 2. [Additionally,] Group-III inboard O2 | | analyzer sample valve SV-2671A-G isolated due to loss of power to station | | 20Y33 bus power. Momentary loss of this power cause[d] the control logic | | for this solenoid valve to de-energize [and] close the valve." | | | | "Due to the 4-kV bus swaps, the following systems were affected on Unit 3: | | RWCU isolated due to loss of station 30Y34 bus power. Loss of this power | | cause[d] the control logic for RWCU to de-energize momentarily and isolate | | the RWCU system. On Unit 3, this was only a [half] isolation; however, this | | still caused a full isolation. Additionally, the Unit 3 [drywell] sump | | outboard isolation valves [(AO-3-20-83 and AO-3-20-95)] isolated closed due | | to the loss of [station] 30Y34 [bus power. The] 'B' loop [drywell | | instrument] N2 supply and torus N2 supply valves [(AO-3969B and AO-3968, | | respectively,)] also isolated due to loss of [power to the solenoid valves. | | This was due to a Group-II isolation signal. The loss of power that caused | | these valves to close was from the same station bus (30Y34).]" | | | | "Current plans are underway to investigate why the 2SU-E [breaker] tripped | | open, and all isolations [have been] reset on both units. [All valves have | | also been re-aligned to their normal positions with the exception of the | | RWCU isolation valves on both units. RWCU system restoration is in | | progress.] Both units remain at 100% power, and operation will continue." | | | | "No [radiation] releases happened as a result of this transient, and no | | increased [radiation] conditions were detected." | | | | The licensee stated that there were no ongoing maintenance or surveillance | | activities related to breaker 2SU-E at the time of this event. All systems | | functioned as expected as a result of this breaker opening. | | | | The licensee notified the NRC resident inspector. | | | | ******************** UPDATE AT 1425 ON 12/27/98 BY TROCINE FROM PHILIP | | PAUTLER ******************** | | | | During a telephone call to the site to verify information, the licensee | | stated that both units were in a 7-day technical specification limiting | | condition for operation as a result of the loss of breaker 2SU-E. The units | | are also in a 15-day technical specification limiting condition for | | operation as a result of the loss of a station blackout line. | | | | The NRC Operations Officer notified the R1DO (White). | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ |Power Reactor |Event Number: 35197 | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ | FACILITY: LIMERICK REGION: 1 |NOTIFICATION DATE: 12/27/1998| | UNIT: [] [2] [] STATE: PA |NOTIFICATION TIME: 17:43[EST]| | RXTYPE: [1] GE-4,[2] GE-4 |EVENT DATE: 12/27/1998| +------------------------------------------------+EVENT TIME: 14:30[EST]| | NRC NOTIFIED BY: JOHN HUNTER |LAST UPDATE DATE: 12/27/1998| | HQ OPS OFFICER: LEIGH TROCINE +-----------------------------+ +------------------------------------------------+PERSON ORGANIZATION | |EMERGENCY CLASS: N/A |JOHN WHITE R1 | |10 CFR SECTION: | | |AINA 50.72(b)(2)(iii)(A) POT UNABLE TO SAFE SD | | |AIND 50.72(b)(2)(iii)(D) ACCIDENT MITIGATION | | |NLCO TECH SPEC LCO A/S | | | | | +-----+----------+-------+--------+-----------------+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ | | | |2 N Y 100 Power Operation |100 Power Operation | | | | +------------------------------------------------------------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | HIGH PRESSURE COOLANT INJECTION (HPCI) DECLARED INOPERABLE DURING | | SURVEILLANCE TESTING DUE TO LOW LUBE OIL PRESSURES | | | | The following text is a portion of a facsimile received from the licensee: | | | | "Unit 2 HPCI was secured and declared inoperable after being placed in | | service for a regularly scheduled surveillance test. During performance of | | the pump, valve, and flow test, a lube oil pressure alarm annunciated due to | | low lube oil pressures in various points throughout the system. All other | | parameters were normal, and the system was operating properly. HPCI was | | then secured, and a normal shutdown of the system was achieved. No other | | abnormalities were identified throughout the entire evolution. | | Investigation continues as to the cause of the low lube oil pressure | | alarm." | | | | The unit was placed in a 14-day technical specification limiting condition | | for operation as a result of this issue. | | | | The licensee plans to notify the NRC resident inspector. | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ |Power Reactor |Event Number: 35198 | +------------------------------------------------------------------------------+ +------------------------------------------------------------------------------+ | FACILITY: PALISADES REGION: 3 |NOTIFICATION DATE: 12/27/1998| | UNIT: [1] [] [] STATE: MI |NOTIFICATION TIME: 19:01[EST]| | RXTYPE: [1] CE |EVENT DATE: 12/27/1998| +------------------------------------------------+EVENT TIME: 17:30[EST]| | NRC NOTIFIED BY: CHARLIE KOZUP |LAST UPDATE DATE: 12/27/1998| | HQ OPS OFFICER: LEIGH TROCINE +-----------------------------+ +------------------------------------------------+PERSON ORGANIZATION | |EMERGENCY CLASS: N/A |JOHN MADERA R3 | |10 CFR SECTION: | | |ADAS 50.72(b)(2)(i) DEG/UNANALYZED COND | | | | | | | | | | | +-----+----------+-------+--------+-----------------+--------+-----------------+ |UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE | +-----+----------+-------+--------+-----------------+--------+-----------------+ |1 N N 0 Hot Shutdown |0 Hot Shutdown | | | | | | | +------------------------------------------------------------------------------+ EVENT TEXT +------------------------------------------------------------------------------+ | DISCOVERY OF BORIC ACID RESIDUE ON A CONTROL ROD DRIVE MECHANISM | | | | "During a plant heatup following a maintenance outage, boric acid residue | | was discovered on control rod drive (CRD) mechanism #2. Further | | investigation determined [that] the leakage was occurring on the CRD | | housing. Further investigation in Hot Shutdown is not possible. The plant | | is being taken to Cold Shutdown to allow disassembly of the CRD housing to | | determine the source of the leakage. This event is being reported as a | | significant reactor coolant system welding or material defect until the | | source of the leakage is confirmed [with the unit] in Cold Shutdown." | | | | The licensee notified the NRC resident inspector. | +------------------------------------------------------------------------------+