Event Notification Report for June 02, 2000

OUTSIDE CONTAINMENT ISOLATION VALVE INOPERABLE DUE TO INCOMPLETE PLANT MODIFICATION

At 0415 CDT on 06/02/00, I&C technicians began to perform tech spec surveillance test #ISF-SB-OA30A to test the operability of 'A' train steam line isolation valve slave relay #K-634. In establishing the initial conditions at step 4.2 of the test procedure, solid state protection system white light #26 was not illuminated as required by the procedure. The procedure was exited at that time and the control room crew was informed of the finding.

The control room crew replaced the light bulb and the light still did not illuminate. Another light bulb, known to be good, was then installed in the light socket. The light still did not illuminate. The Shift Supervisor contacted the System Engineer at approximately 0530 CDT when the engineer arrived onsite, and requested that the engineer investigate what the white light indicated when the light was not illuminated.

After review of the system schematics, the engineer found that there was the possibility of outside containment isolation valve #EGHV-0061 being INOPERABLE if relay #K-802 did not function properly. (Reference electrical drawing #E-23EG09A.) This situation was reported to the control room crew.

The Shift Supervisor declared valve #EGHV-0061 INOPERABLE using the time of discovery at 0415 CDT and closed the valve and deenergized power to the valve per Tech Spec action statement 3.6.3.A at 0800 CDT. Equipment out of service log entry #7986 was made.

I&C technicians were dispatched to support troubleshooting efforts. After some initial troubleshooting, some results did not agree with the drawing. The engineer noted the drawing showed that the circuitry had recently been changed by Plant Modification #CMP 98-1020. The drawing had been updated on 04/07/00.

The engineer called the Construction Supervisor of the plant modification installation. The supervisor reviewed the modification package and found a connection between a terminal block at the motor control center for valve #EGHV-0061 and the solid state protection system cabinet #SB030A had not been performed. This made containment isolation valve #EGHV-0061 INOPERABLE because it would not close on a phase B containment isolation signal. The control room crew was notified of this finding. This finding meant that the valve had been INOPERABLE since the installation of the plant modification on 04/06/00.

The Construction Supervisor initiated field change notice #FCN-11 to plant modification package #MP 98-1020 and initiated work document #W657017 to correct the circuitry wiring. Retest documents #R657017A and #R6S70173 was also initiated for post maintenance testing of the circuit.

The licensee determined that this event was reportable to the NRC at 1030 CDT.

The licensee notified the NRC Resident Inspector.

REACTOR CORE ISOLATION COOLING SYSTEM INOPERABLE DUE TO A FAULTY LEVEL SWITCH -

At 1721 on 06/02/00, Nine Mile Point Unit 2 received a Reactor Core Isolation Cooling (RCIC) System high point vent low level annunciator alarm. This alarm came in and cleared repeatedly. The licensee declared the RCIC System inoperable but functional and entered Technical Specification 3.7.4 which requires the RCIC System to be restored to operable status within 14 days. The licensee closed the RCIC System turbine trip throttle valve, #2ICS*MOV150 in accordance with the annunciator response procedure. The licensee then performed the RCIC System fill and vent procedure #N2-OSP-ICS-M001 satisfactorily with a solid stream of water being vented and no evidence of air in the system. The high point vent low level annunciator alarm remained in solid following the fill and vent procedure. The licensee suspects that a faulty high point vent level switch is the problem and prepared a Problem Identification to repair the switch. The licensee has returned the RCIC System to available status (but still inoperable) and is reviewing compensatory actions for the faulty level switch to support the return of the RCIC System to operable status.

This event has no effect on Unit 1 which is at 100% power.

The licensee plans to notify the NRC Resident Inspector.

* * * RETRACTED AT 1446 EDT ON 6/21/00 BY MATT WALDECKER TO FANGIE JONES * * *

"On June 2, 2000 at 1721 hours, the reactor core isolation cooling system was declared inoperable when a high point vent level low annunciator alarmed and cleared repeatedly. The reactor core isolation cooling trip throttle valve was closed in accordance with the annunciator response procedure.

"Subsequent review has determined that the high point vent level low annunciator alarming and clearing repeatedly was due to a failed level switch. Correct high point vent water level was verified utilizing an approved operating procedure. 50.72(b)(2)(iii) and 50.73(a)(2)(v) reporting criteria covers an event or condition where structures, components, or trains of a safety system could have failed to perform their safety function because of equipment failures. The failure of the high point level switch does not constitute an event or condition which rendered the Reactor Core Isolation Cooling System incapable of performing its safety function. In addition, the level switch is only used to warn the operators of decreasing water inventory in the reactor core isolation cooling discharge line. No credit is taken for the level switch in any safety analyses and does not directly control the removal of residual heat (the safety function) from the Reactor Vessel. Therefore, this event is not reportable.

"The operator action to close the reactor core isolation cooling trip throttle valve in accordance with the annunciator response procedure does not constitute an event or condition as discussed in the NUREG-1022. Therefore, notification of this event is being retracted."

The licensee notified the NRC Resident Inspector. The R1DO (Robert Summers) was notified.

24-HOUR NRC 91-01 BULLETIN REPORT INVOLVING POTENTIAL LOSS OF CRITICALITY CONTROL IN SHUTDOWN CELLS

"On 6/2/00 the Plant Shift superintendent was notified of a potential NCSA noncompliance. NCSAs 326_013, NCSA 330_004, and NCSA 333_015 require that cells that are shutdown and at a UF6 negative be buffered with dry air or nitrogen to maintain moderation control as part of double contingency. For cells that have less than a safe mass, procedure guidance allows the cell to be maintained less than atmospheric pressure, when not at a UF6 negative. Various leaks (either from the dry air system or from wet atmospheric air) can enter the cell allowing pressure to increase. This pressure must then be evacuated to maintain the cell less than atmospheric pressure. Repeated cycles of 'leak up' and evacuation will eventually achieve a UF6 negative unknown to operators since there are no periodic sampling requirements. The NCS requirement to buffer a cell within eight hours of achieving a UF6 negative may then be violated because the state of a UF6 negative is not known.

"Presently all cells that are shutdown that have less than a safe mass in them are at a UF6 negative, and there is currently no violation of this moderation control. However, it cannot be guaranteed that this control was not violated during past operations, and is being reported as a loss of one control.

"SAFETY SIGNIFICANCE OF EVENTS:

"The safety significance of this event is low. Only affected cells that when shutdown have less than a safe mass of material in them. Failure to establish or maintain the buffer as required could result in wet air entering a shutdown cell. This would moderate a UO2F2 deposit due to the hygroscopic properties of UO2F2. If this unbuffered condition were permitted to continue for longer periods, the H/U of the deposit could eventually reach a maximum of 4 (the maximum H/U ratio of a deposit exposed to ambient cascade building air is 4). However, due to being less than a safe mass, a criticality could not occur.

"POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO[S] OF HOW CRITICALITY COULD OCCUR):

"For a criticality to occur the mass of the deposit would have to be greater than a safe mass, moderation level would have to reach an H/U ratio of 4, the deposit would have to be reflected.

"CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.):

"The controlled parameters for this event are mass and moderation.

"ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE OF CRITICAL MASS):

"The highest possible enrichment for event is 20% and the material will be at or below a safe mass.

"NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES:

"The failure in this case is the implementation of the control on moderation.

"CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEM AND WHEN EACH WAS IMPLEMENTED:

[Not specified]."

Department Operating Instructions (DOIs) have been issued pending procedural revisions to address this deficiency. The NRC Resident Inspector and DOE Site Representative have been informed.