Event Notification Report for February 21, 2001
U.S. Nuclear Regulatory Commission
Operations Center
Event Reports For
02/20/2001 - 02/21/2001
** EVENT NUMBERS **
37719 37757 37766 37767
!!!!!!!!! THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED !!!!!!!
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|Power Reactor |Event Number: 37719 |
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| FACILITY: COOPER REGION: 4 |NOTIFICATION DATE: 02/06/2001|
| UNIT: [1] [] [] STATE: NE |NOTIFICATION TIME: 10:43[EST]|
| RXTYPE: [1] GE-4 |EVENT DATE: 02/06/2001|
+------------------------------------------------+EVENT TIME: 01:48[CST]|
| NRC NOTIFIED BY: S JOBE |LAST UPDATE DATE: 02/20/2001|
| HQ OPS OFFICER: JOHN MacKINNON +-----------------------------+
+------------------------------------------------+PERSON ORGANIZATION |
|EMERGENCY CLASS: N/A |GARY SANBORN R4 |
|10 CFR SECTION: | |
|*DEG 50.72(b)(3)(ii)(A) DEGRAD COND DURING OP | |
| | |
| | |
| | |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|1 N Y 100 Power Operation |100 Power Operation |
| | |
| | |
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EVENT TEXT
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| PRIMARY CONTAINMENT DECLARED INOPERABLE |
| |
| Primary Containment was declared inoperable at 0148 CST on February 6, 2001, |
| due to the failure of meeting the acceptance criteria for the suppression |
| chamber to drywell vacuum breaker operation. |
| |
| While performing the 31 day surveillance, PC-AO-NRV30, suppression chamber |
| to drywell vacuum breaker failed to indicate full close. The valve was |
| subsequently stroked a second time and full closure indication was received. |
| Estimated time of 2 minutes and 6 seconds when valve did not indicate full |
| close. During this time frame when the valve was not indicating full close, |
| Primary Containment was inoperable. Upon full closure of the valve, Primary |
| Containment was returned to operable status. |
| |
| Engineering continues to evaluate the condition. TS action statement of LCO |
| 3.6.1.8 B, requires the vacuum breaker to be closed in 12 hours. Required |
| action not completed in the completion time requires the reactor to be in |
| Mode 3 (Hot Shutdown) in twelve hours in Mode 4 (Cold Shutdown) in |
| thirty-six hours. |
| |
| The NRC Senior and Resident Inspectors have been notified. |
| |
| * * * RETRACTED AT 1638 EST ON 2/20/01 BY ANDREW OHRABLO TO FANGIE JONES * * |
| * |
| |
| "The suppression chamber to drywell vacuum breaker has two types of position |
| indication available. They are a disc position switch, which only provides a |
| red light indication for open, and a hinge position switch, which provides a |
| red light indication for open and a green light indication for closed. |
| Subsequent evaluation determined that the hinge position indication did show |
| the vacuum breaker in the closed position upon the initial stroking and is |
| adequate for making this determination, i.e., proper calibration. The disc |
| position switch did not turn out the red indication light because of the |
| slow closure of the disc due to what is believed to be a faulty |
| non-essential air operator. |
| |
| "CNS investigation has found that the suppression chamber to drywell vacuum |
| breaker was capable of performing its safety function in the open and close |
| directions during this event. The suppression function of the Primary |
| containment was not degraded as originally thought. Therefore, this event is |
| not reportable under the requirements of 10CFR50.72 and event 37719 is |
| retracted." |
| |
| The licensee notified the NRC Resident Inspector. The R4DO (Linda Smith) |
| was notified. |
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!!!!!!!!! THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED !!!!!!!
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|Power Reactor |Event Number: 37757 |
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| FACILITY: GRAND GULF REGION: 4 |NOTIFICATION DATE: 02/16/2001|
| UNIT: [1] [] [] STATE: MS |NOTIFICATION TIME: 19:41[EST]|
| RXTYPE: [1] GE-6 |EVENT DATE: 02/16/2001|
+------------------------------------------------+EVENT TIME: 16:30[CST]|
| NRC NOTIFIED BY: MARTY McADORY |LAST UPDATE DATE: 02/20/2001|
| HQ OPS OFFICER: BOB STRANSKY +-----------------------------+
+------------------------------------------------+PERSON ORGANIZATION |
|EMERGENCY CLASS: N/A |GREG PICK R4 |
|10 CFR SECTION: | |
|*IND 50.72(b)(3)(v)(D) ACCIDENT MITIGATION | |
| | |
| | |
| | |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|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
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| HIGH PRESSURE CORE SPRAY SYSTEM DECLARED INOPERABLE |
| |
| "During performance of 1C3 battery all-cell checks, battery cell #38 was |
| found to be >0.020 below the average for specific gravity. Tech Spec 3.8.6, |
| 'Battery Cell Parameters,' requires declaring 1C3 battery inoperable. This |
| caused entry into Tech Spec 3.8.4 Action D, which is to declare the High |
| Pressure Core Spray system inoperable. This requires entry into a 14 day |
| LCO. This event is reportable since High Pressure Core Spray is a single |
| train system." |
| |
| The NRC resident inspector has been informed of this event by the licensee. |
| |
| * * * RETRACTED AT 1549 EST ON 2/20/01 BY CHRIS MILLER TO FANGIE JONES * * |
| * |
| |
| The licensee is retracting this event notification. After further review it |
| has been determined that the entry conditions for the LCO were not met and |
| the division 3 batteries were never inoperable. |
| |
| The licensee notified the NRC Resident Inspector. The R4DO (Linda Smith) |
| has been notified. |
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|Power Reactor |Event Number: 37766 |
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| FACILITY: COOPER REGION: 4 |NOTIFICATION DATE: 02/20/2001|
| UNIT: [1] [] [] STATE: NE |NOTIFICATION TIME: 01:56[EST]|
| RXTYPE: [1] GE-4 |EVENT DATE: 02/19/2001|
+------------------------------------------------+EVENT TIME: 21:08[CST]|
| NRC NOTIFIED BY: JOHN MYERS |LAST UPDATE DATE: 02/20/2001|
| HQ OPS OFFICER: STEVE SANDIN +-----------------------------+
+------------------------------------------------+PERSON ORGANIZATION |
|EMERGENCY CLASS: N/A |GREG PICK R4 |
|10 CFR SECTION: | |
|*SHU 50.72(b)(2)(i) PLANT S/D REQD BY TS | |
| | |
| | |
| | |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|1 N Y 100 Power Operation |54 Power Operation |
| | |
| | |
+------------------------------------------------------------------------------+
EVENT TEXT
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| TECH SPEC REQUIRED SHUTDOWN COMMENCED AFTER DECLARING BOTH STANDBY GAS |
| TREATMENT (SGT) TRAINS INOPERABLE |
| |
| "While performing Surveillance 6.SUMP.101, Z SUMP AND AIR EJECTOR HOLDUP |
| LINE DRAIN OPERABILITY TEST (IST), Z-1 sump pump exceeded its operability |
| time limit of 151 seconds by 3 seconds. When Z-2 sump pump was subsequently |
| tested, the pump failed to start on the essential HI-HI level switch. Both |
| sump pumps were declared INOPERABLE. These pumps support Standby Gas |
| Treatment OPERABILITY. The SGT line from the plant runs underground to the |
| Elevated Release Point tower, and the offgas line and SGT both enter this |
| sump. The pumps remove condensation from both the offgas lines and SGT, and |
| must be available post-accident to prevent flooding of the SGT lines. |
| |
| "Per administrative direction in the Surveillance procedure, both trains of |
| SGT were declared INOPERABLE at 2108. Per Technical Specification 3.6.4.3, |
| Condition D, with two SGT subsystems INOPERABLE in Mode 1, the Required |
| Action is to enter LCO 3.0.3 immediately. LCO 3.0.3 requires the plant to |
| be in Mode 2 within 7 hours, Mode 3 within 13 hours, and Mode 4 within 37 |
| hours. A power reduction was commenced at 2250. Present power level is |
| 54%. |
| |
| "Engineering personnel have responded to the plant and are evaluating the |
| two conditions." |
| |
| The above surveillance is performed quarterly. The licensee noted a past |
| history of problems with the system's level switches. The current rate of |
| power reduction is approximately 100 MW/hr or 12-15% reactor power. The |
| licensee informed the NRC resident inspector. |
| |
| * * * UPDATE 0441 2/20/01 FROM TERRY BORGAN TO S. SANDIN * * * |
| |
| Tech Spec required shutdown exited at 0334CST after engineering determined |
| that one train of SGT was OPERABLE. The Unit remains in a 7-day LCO for the |
| other INOPERABLE train. Notified R4DO(Pick). |
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|Fuel Cycle Facility |Event Number: 37767 |
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| FACILITY: PORTSMOUTH GASEOUS DIFFUSION PLANT |NOTIFICATION DATE: 02/20/2001|
| RXTYPE: URANIUM ENRICHMENT FACILITY |NOTIFICATION TIME: 22:30[EST]|
| COMMENTS: 2 DEMOCRACY CENTER |EVENT DATE: 02/20/2001|
| 6903 ROCKLEDGE DRIVE |EVENT TIME: 08:46[EST]|
| BETHESDA, MD 20817 (301)564-3200 |LAST UPDATE DATE: 02/20/2001|
| CITY: PIKETON REGION: 3 +-----------------------------+
| COUNTY: PIKE STATE: OH |PERSON ORGANIZATION |
|LICENSE#: GDP-2 AGREEMENT: N |MARK RING R3 |
| DOCKET: 0707002 |JOSEPH HOLONICH NMSS |
+------------------------------------------------+FRANK CONGEL IRO |
| NRC NOTIFIED BY: ERIC SPAETH | |
| HQ OPS OFFICER: FANGIE JONES | |
+------------------------------------------------+ |
|EMERGENCY CLASS: N/A | |
|10 CFR SECTION: | |
|NBNL RESPONSE-BULLETIN | |
| | |
| | |
| | |
| | |
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EVENT TEXT
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| NRC BULLETIN 91-01 24 HOUR REPORT |
| |
| The following is a portion of a faxed report: |
| |
| On 02/20/01 at 0848 hours the Plant Shift Superintendent's office was |
| informed that a Nuclear Criticality Safety Analysis (NCSA) was deficient. |
| NCSA-PLANT088, Storage of Abandoned Equipment, utilizes the NCS calculation |
| document NCS-CALC-98-029, which contains the following non-conservative |
| assumptions: |
| |
| The KENO model used a radius of 6.35 cm to model the inner diameter of a |
| 5-inch pipe. This does not bound all nominal 5-inch diameter pipe. Standard |
| 5-inch pipe can have an inner diameter of 5.345 inches (13.5763 cm) which |
| would require a radius of 6.7882 cm. |
| |
| This document modeled a UO2F2 - H2O mixture with an H/U ratio of 4. The use |
| of this H/U ratio is acceptable for cascade piping due to the way the |
| cascade is operated. It is not acceptable for use in other buildings (i.e. |
| X-705, X-700, and X710) if the pipe is filled with fissile material. An H/U |
| ratio of at least 16 should have been used to bound pipes in the other |
| buildings. |
| |
| NCS-CALC-98-029 provides part of the basis for defining what a safe geometry |
| is in NCSA-PLANT088.A00 (Storage of Abandoned Equipment). The calculation |
| models a spacing violation between two 5.0-inch diameter 10-ft long pipes |
| containing 100% enriched UO2F2 at an H/U of 4. Each pipe modeled in the |
| calculation contains approximately 125,000 grams of U-235 at 100% |
| enrichment. The USEC possession limit for HEU outside of shutdown cascade |
| equipment is 1000 grams U-235. |
| |
| Control 1a in NCSA-PLANT088.A00 defines a safe geometry based on having a |
| nominal pipe diameter of 5-inches or less, as well as limiting the length of |
| the pipe to less than 10-feet and specifying that the pipe has not been |
| exposed to oily material. Since 'nominal' 5-inch diameter pipes may have |
| diameters slightly larger than 5.0-inches, control 1a is not consistent with |
| the assumption in calculation NCS-CALC-98-029 of exactly 5.0-inch diameter. |
| Therefore, NCSA-PLANT088.A00 is technically deficient, NCSA-PLANT088.A00 is |
| currently active in various buildings on plant site. None of the equipment |
| currently regulated by NCSA-PLANT088.A00 used the definition of safe |
| geometry (as defined in control 1A in NCSA-PLANT088.A00) to show double |
| contingency. Rather, all equipment currently under NCSA-PLANT088 is |
| controlled based on being below a safe mass, which the NCSA allows as an |
| alternative to controlling the geometry. Therefore, double contingency can |
| still be shown for all equipment currently regulated by NCSA-PLANT088.A00 |
| (based on spacing and mass controls). |
| |
| As part of the response to this incident, other NCSAs were investigated |
| which referenced either NCS-CALC-098-029 or NCSA-PLANT008 as part of their |
| safety basis, It was determined that NCSA-PLANT062.A04 (Cascade Maintenance |
| Equipment Removal and Storage) has the same problem as NCSA-PLANT088.A00. In |
| addition, NCSA-0705_ 041.A01 (Material Handling and Storage in X-705) and |
| NCSA-PLANT048.A04 (Contaminated Metal) also reference either calculation |
| NCS-CALC-98-029, NCSA-PLANT088.A00, or PLANT062.A04 as part of their safety |
| basis for storage of favorable geometry equipment. While there may be items |
| stored under these NCSAs based on the controls defining favorable geometry, |
| none of these items individually can contain greater than a safe mass |
| because of the requirements of TSRs 2.2.3.16 and 2.7.3.15. These TSRs |
| require any removed cascade equipment containing greater than a safe mass |
| under optimum moderation conditions to be decontaminated within 72 hours. |
| Since there can be no equipment stored under any of the affected NCSAs |
| containing greater than a safe mass, this incident is being reported to the |
| NRC as a 24-hour event report. |
| |
| SAFETY SIGNIFICANCE OF EVENTS: |
| |
| The non-conservative assumption in NCS-CALC-98-029 has a low safety |
| significance for the following reasons: |
| |
| The calculation assumed two 5-inch 10 foot long pipes completely filled with |
| a UO2F2-H2O mixture (H/U ratio of 4) containing approximately 125,000 grams |
| of 100% enriched U-235. This case bounds the entire operating history of the |
| plant. Current plant requirements limit the production of enriched uranium |
| to 10 wt% U-235. Any material greater than 10% is currently contained within |
| shutdown cascade piping (which is covered by other NCSAs not affected by |
| this incident), or is limited to 1000 grams U-235 by the USEC possession |
| limits. |
| |
| There is no equipment currently controlled by NCSA-PLANT088.A00 that uses a |
| safe geometry as one control for double contingency. |
| |
| While there may be equipment covered under NCSAs PLANT062, PLANT048, or |
| 0705_041 that use safe geometry as a control, TSRs 2.2.3.16 and 2.7.3.15 |
| (Removed Equipment with Deposits) ensure that any such equipment containing |
| greater than a safe mass is decontaminated to less than or equal to a safe |
| mass within 72 hours of removal. The safe mass required by these TSRs is |
| based on optimum moderation conditions. As a result of these TSRs and their |
| implementing procedures, there is no removed equipment currently stored on |
| plant site under any of the affected NCSAs which contains greater than a |
| safe mass. Since the safe mass is defined as less than half of the minimum |
| credible critical mass, a criticality would not have occurred even if a |
| spacing violation had occurred. |
| |
| The calculation in question was intended to demonstrate subcriticality in |
| the event of a spacing violation between two favorable geometry pipes. Since |
| there are no known spacing violations between such equipment, there remains |
| at least one control in place to prevent criticality (spacing) in all cases. |
| The normal storage of favorable geometry equipment in a properly spaced |
| configuration was not affected by this discovery. |
| |
| POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO[S] OF HOW |
| CRITICALITY COULD OCCUR): |
| |
| Two 10 foot long 5 inch pipes containing a mixture of UO2F2-H2O mixture (H/U |
| ratio of 16) containing I00 wt% U-235 placed adjacent to each other could |
| achieve criticality. |
| |
| CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.): |
| |
| The controlled parameters for equipment which could be affected by this |
| event are spacing and geometry. |
| |
| ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS |
| LIMIT AND % WORST CASE OF CRITICAL MASS): |
| |
| No specific equipment was identified as being out of compliance. Therefore, |
| the amount, enrichment or form is not known. However, it is known that no |
| individual piece of equipment stored under the affected NCSAs contains |
| greater than a safe mass, due to the TSR requirements. |
| |
| NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION |
| OF THE FAILURES OR DEFICIENCIES: |
| |
| The calculation document for a spacing violation between two favorable |
| geometry components contained a non-conservative assumption which was not |
| properly flown into the NCSA controls. The spacing control remained in |
| place. Thus, one control used for double contingency was rendered invalid. |
| The deficiency will be corrected by revising the NCSA controls to be |
| consistent with the calculation. |
| |
| CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEM AND WHEN EACH WAS IMPLEMENTED: |
| |
| Daily Operating Instructions (DOI) stating "No further equipment shall be |
| implemented under NCSA-PLANT088 until the deficiency Is corrected." |
| |
| The licensee has notified the NRC Resident Inspection and DOE. |
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Page Last Reviewed/Updated Thursday, March 25, 2021
Page Last Reviewed/Updated Thursday, March 25, 2021