Event Notification Report for April 11, 2001

SECURITY REPORT

Unescorted access granted inappropriately. Immediate compensatory measures taken upon discovery.

Refer to the HOO Log for additional details.

The licensee notified the NRC Resident Inspector.

See EN #37909.

LOSS OF EMERGENCY PLAN SIRENS

The site reported the loss of six emergency plan sirens which constitutes a major loss of emergency offsite communications for greater than one hour. This was caused by a loss of power due to high winds and downed power lines. Power was restored to the sirens at 0807 CDST.

The NRC Resident Inspector was notified. The licensee will make a press release to the news media.

NATIONAL WEATHER SERVICE TONE-ALERT RADIOS OUT OF SERVICE FOR PLANNED MAINTENANCE

The following text is a portion of a facsimile received from the licensee:

"[The] Emergency Planning Department at Nine Mile Point [Unit 1 was] notified by Jim Holman of [the] Oswego County Emergency Planning Department that the tone-alert radios for the National Weather Service (NWS) were out of service (OOS) as of 1118 on 04/11/01 and are expected to be returned to service (RTS) at 1400 on 04/11/01. The system was taken OOS for planned maintenance. [The] Sheriff's Department [is] prepared to perform route alerts if necessary per procedure EPIP-EPP-30 (Prompt Notification System Problem Response). [The] control room [was] notified [of the event] at 1125 on 04/11/01."

"(10 CFR 50.72(b) and 10 CFR 50.72(a)(2) apply.)"

The licensee notified the NRC resident inspector and county sheriff. The licensee also plans to notify applicable local and state agencies.

(Refer to event #37912 for a similar event notification from Fitzpatrick.)

* * * UPDATE ON 4/11/01 AT 1523 BY SHEEHAN TO GOULD * * *

The radio was back in service at 1515.

The NRC Resident Inspector will be notified. Reg 1 RDO(Linville) was notified

NATIONAL WEATHER SERVICE TONE-ALERT RADIOS OUT OF SERVICE FOR PLANNED MAINTENANCE

The following text is a portion of a facsimile received from the licensee:

"[The] Control Room [and] Emergency Planning Department [were] notified (via [the] Nine Mile Point Unit 1 Control Room) by Jim Holman of [the] Oswego [County] Emergency Management Office that the tone-alert radios for the National Weather Service (NWS) were out of service (OOS) as of 1118 on 04/11/01 and are expected to be returned to service (RTS) at 1400 on 04/11/01. The system was taken OOS for planned maintenance. [The] Oswego Sheriff's Department is prepared to perform route alerts if necessary."

"Review - 10 CFR 50.72(b) [and] 10 CFR 50.72(a)(2)"

The licensee notified the NRC resident inspector and plans to notify applicable local and state agencies.

(Refer to event #37911 for a similar event notification from Nine Mile Point.)

FAILURE OF STANDBY GAS TREATMENT SYSTEM CHARCOAL FILTERS TO PASS A TECHNICAL SPECIFICATION REQUIRED SURVEILLANCE

The licensee reported that the 'A' train of standby gas treatment did not pass a test involving an in-place charcoal absorber test with halogenated hydrocarbon tracer (freon). This technical specification required surveillance test is performed approximately every 18-months.

The unit was placed in a 7-day limiting condition for operation for the 'A' train of standby gas treatment prior to the test. The unit remains in that LCO as a result of this test. The 'B' train is currently operable.

The licensee's investigation is in progress. At this time, the licensee believes that the problem is the result of bypass leakage. The licensee plans to verify the root cause and retest the system tomorrow.

This event was reported as an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material and mitigate the consequences of an accident.

The licensee notified the NRC resident inspector and plans to notify state and local officials.

NRC BULLETIN 91-01 24 HOUR NOTIFICATION

AN NCS ADMINISTRATIVE REQUIREMENT NOT MET.

On 04/11/01, it was discovered that C-333 Unit 2 Cell 1 freon systems were at zero freon level without current independent verification documentation that the cell was less than 1.0 wt% U235 in violation of NCSA CAS.011. An independent assay verification was performed in May of 2000, however the cell was subsequently placed onstream and taken back offstream and shutdown in October of 2000. Since shutdown, independent assay verification had not been performed when the freon was drained and prior to implementation of NCSA CAS.011. Due to independent assay verification not being performed prior to implementation of NCSA CAS.011, and NCS administrative requirement was not met. Upon discovery, independent assay verification was immediately performed and cell assay was determined to be less than 1.0 wt% U235.

SAFETY SIGNIFICANCE OF EVENT:

Double contingency was not maintained. Although the required documentation was not verified at the tome the R-114 level was removed from the cell, the assay of the cell was well known through historical process knowledge. Upon discovery, the historical cascade gradient was reviewed and it was determined that the cell was less than 1.0 wt% U235.

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

In order for criticality to be possible, the shutdown cell would need to have an unsafe mass of moderated uranium with an enrichment greater than 1.0 wt% U235.

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

Double contingency for this scenario is established by implementing two controls on assay.

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

0.7183 wt% U235.

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

The first leg of double contingency is based on verification that the equipment contains uranium enriched to less than 1.0 wt% U235. The verification of assay was not performed. Therefore, the control was violated and the first leg of double contingency was lost.

The second leg of double contingency is based on independent verification that the equipment contains uranium enriched to less than 1.0 wt% U235. This independent verification was not performed. Therefore, the control was violated and the second leg of double contingency was lost.

Since double contingency is based on two controls on assay, double contingency was not maintained.

CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED:

An independent assay verification was performed and documented, which indicated that the assay was less than 1.0 wt% U235.

The NRC Resident Inspector was notified of this event by the Certificate Holder.

INADVERTENT LOSS OF 'A' RPS BUS

The following is taken from a faxed report:

This 60-day optional report in accordance with 10CFR50.73(a)(1), is being made under the reporting requirement of 10CFR50.73(a)(2)(iv)(A) to describe an invalid actuation of the Containment Isolation System.

On April 11, 2001, at 0005 hours, the control room received an alarm for loss of the 'A' Reactor Protection System (RPS) bus. As a result of the loss of the 'A' RPS bus the following actuations occurred: an A1 & A2 RPS half scram, a Nuclear Steam Supply System Shutoff (NSSSS) logic A & C trip, tripping of the 'A' and 'B' Reactor Water Clean Up (RWCU) pumps due to closure of the inboard isolation valve BG-HV-F001, recirculation sampling isolation, and closure of the inboard Main Steam Line Drain valve AB-HV-F016

The 'A' RPS bus was shifted to the alternate feed at 0023 and the RPS A1 & A2, the NSSSS, and the primary containment isolation signals (PCIS) were reset. At 0036, recirculation sampling was restored. Valve, BG-HV-F001 and AB-HV-F016 were reopened at 0039 hours.

The above actuations and isolations were expected as a result of the loss of the 'A' RPS bus. These actions and isolations were due to an invalid signal resulting from the inadvertent de-energization of the 'A' RPS bus.

Fire Protection Operators were performing testing of the smoke detectors in the RPS motor-generator (MG) set room using a test pole. When the Fire Protection Operator in the overhead was handing the test pole to the Fire Protection Operator on the floor, the pole slipped and struck breaker switch for H1SB-1AN410 (A RPS EPA breaker), causing the breaker to open. Opening of the breaker lead to the loss of the 'A' RPS bus.

After determining that no damage occurred to breaker H1SB-1AN410, the 'A' RPS was restored to the normal power source.

The impact on the plant safety from this event was minimal. The isolations and equipment losses during the event caused only a minor plant transient and the equipment performed as expected. After the plant was stabilized and the cause of the loss of the 'A' RPS was identified, the half scram was reset.

This event has been entered into the corrective action program.


The licensee intends to notify the NRC Resident Inspector.

INVALID PRIMARY CONTAINMENT ISOLATION SYSTEM ACTUATION DURING POST-MODIFICATION TEST ACTIVITIES

"This 60-day telephone notification is being made under reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A), to describe an invalid actuation of the primary containment isolation system.

"Unit 2 was in mode 5 on day 24 of a scheduled refueling outage with the reactor cavity flooded. Unit 3 was at 100 percent power. The impact on the facility from the event was minimal. The plant equipment responded correctly.

"On April 11, 2001 at 0827 hours Central Daylight Time, Unit 2 received invalid Group 2, 3, 6 and 8 Primary Containment Isolation Signals (PCIS) during performance of Post-Modification Testing (PMT) activities. The PCIS isolations were a result of an invalid low reactor water level signal generated when the power fuses were removed during the test,

"The following actuations/isolations occurred: (Group 3) Reactor Water Cleanup system isolated, (Group 6) Stand by Gas Treatment system Trains A, B, and C started, Control Room Emergency Ventilation B started, and ventilation systems that were not removed from service. Groups 2 and 8 components were removed from service to support outage activities, subsequently, no equipment response occurred.

"The effected systems were returned to their pre-event configuration. There were no safety consequences or compromises to the health and safety of the public. The event was entered into TVA's corrective action program for resolution.

"The NRC Site Resident Inspector has been notified."