United States Nuclear Regulatory Commission - Protecting People and the Environment
Home > NRC Library > Document Collections > Reports Associated With Events > Event Notification Reports > 2001

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 THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED  !!!!!!!
+------------------------------------------------------------------------------+
|Power Reactor                                    |Event Number:   37719       |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| 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  |
|                                                   |                          |
|                                                   |                          |
+------------------------------------------------------------------------------+
                                   EVENT TEXT                                   
+------------------------------------------------------------------------------+
| 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.                                                                |
+------------------------------------------------------------------------------+

!!!!!!!!! THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED  !!!!!!!
+------------------------------------------------------------------------------+
|Power Reactor                                    |Event Number:   37757       |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| 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                                   
+------------------------------------------------------------------------------+
| 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.                                                           |
+------------------------------------------------------------------------------+

+------------------------------------------------------------------------------+
|Power Reactor                                    |Event Number:   37766       |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| 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                                   
+------------------------------------------------------------------------------+
| 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).                                |
+------------------------------------------------------------------------------+

+------------------------------------------------------------------------------+
|Fuel Cycle Facility                              |Event Number:   37767       |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| 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      |                             |
|                                                |                             |
|                                                |                             |
|                                                |                             |
|                                                |                             |
+------------------------------------------------------------------------------+

                                   EVENT TEXT                                   
+------------------------------------------------------------------------------+
| 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.               |
+------------------------------------------------------------------------------+