Event Notification Report for November 03, 1999

LEGACY ITEM - TWO ERRORS OCCURRED ON A U235 MASS LOG

NRC BULLETIN 91-01 24 HOUR NOTIFICATION

On 1/3/99 at 1645 hrs the Plant Shift Superintendent (PSS) was notified that a Nuclear Criticality Safety Approval
(NCSA) requirement was not being performed in the X-710 ES&H Analytical Labs. Building personnel identified that two errors had occurred on the U235 mass log which is used for NCSA compliance verification. The first error was a [non-conservative] mathematical addition error causing an incorrect total to be reported on the Mass log. The second error was that a sample container was inadvertently not logged in on the mass log. This NCS anomaly is a legacy item in that this error was entered into the log on March of 1998.

Requirement 1 of NCSA-0710_25.AOO states in part; Samples in any room enriched to 1% or greater U235, will be limited to one group of (30g U235) per room. This will be ensured by maintaining a room inventory log of U235 mass in labeled containers. Each log entry will consist of the U235 mass value plus analytical uncertainty and will be:

a. made by a knowledgeable person "PRIOR" to bring the samples into the room, and
b. verified by a second knowledgeable person "PRIOR" to bringing the samples into the room.

Both errors were in the non-conservative direction, but the total mass limit for the room 30g U235 was never exceeded [actual amount was 28.851g]. These errors show that both the first and second contingency control were violated.

At the direction of the Plant Shift Superintendent the requirements for an NCS anomalous condition were initiated and the area boundaried off

THERE WAS NO LOSS OF HAZARDOUS/RADIOACTIVE MATERIAL OR RADIOACTIVE/RADIOLOGICAL. CONTAMINATION EXPOSURE AS A RESULT OF THIS EVENT.

SAFETY SIGNIFICANCE OF THE EVENT:

The safety significance of the event is low. The U235 mass in the group was never above the NCSA requirement. However, both controls on the mass requirement were violated.

POTENTIAL CRITICALITY PATHWAY INVOLVED (BRIEF SCENARIOs OF HOW CRITICALITY COULD OCCUR):

Repeated mass violations could result in a greater than safe mass being in the room. Since moderation is not controlled, a spacing violation could have allowed the uranium to reach a critical configuration.

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

Mass, volume, and interaction (spacing) was controlled. By incorrectly logging the mass of one sample and neglecting to log the mass of a separate sample, both the first and second contingency controls was violated.

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

The highest mass of U235 in the group was 28.851 grams. Enrichment of this operation is not controlled, but it is not expected to be 10% assay due to plant production limitations. The form of the uranium varies based on the specific samples involve, although uranyl fluoride, uranyl nitrate, uranium tetra fluoride and other forms would be expected. This represents less than 4% of critical mass.

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

The control on this process included a first and second check to ensures the U235 mass of each sample is recorded and a running total maintained to prevent exceeding a limit of 30 grams U235. Both the first and second check were violated in two separate cases.

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

At the direction of the Plant Shift Superintendent the requirements for an NCS anomalous condition were initiated and the are boundaried off. Lab personnel made corrections to log error and mass was verified at 1700 hours.

The NRC Resident Inspector was notified of this legacy event by the certificate holder.

- FOUR OF SIXTEEN OFFSITE EMERGENCY SIRENS INOPERABLE AND BEING REPAIRED -

Four of 16 offsite emergency sirens in Harriman State Park, Orange County, NY, are inoperable due to the loss of an electrical line to the park during a thunderstorm. The line is being repaired.

The licensee plans to notify the NRC Resident Inspector.

Refer to identical Event #36391 for Unit 3.

- FOUR OF SIXTEEN OFFSITE EMERGENCY SIRENS INOPERABLE AND BEING REPAIRED -

Four of 16 offsite emergency sirens in Harriman State Park, Orange County, NY, are inoperable due to the loss of an electrical line to the park during a thunderstorm. The line is being repaired.

The licensee notified the NRC Resident Inspector.

Refer to identical Event # 36390 for Unit 2.

- Low Pressure Injection System removed from Engineered Safeguards alignment due to erroneous procedure -

At 0230 on 11/03/99, both trains of the Low Pressure Injection (LPI) System were removed from their normal Engineered Safeguards (ES) alignment due to an erroneous procedure. Approximately 20 minutes later, the proper ES alignment was restored after the operators questioned the valve position specified by the procedure.

Although this event was terminated at approximately 0250 on 11/03/99, the potential impact on system operability remained in question. Engineering was notified and began evaluating operability. This included discussions with Operations as to expected actions, alarm responses, etc. It was concluded that operability could not be assured without a detailed analysis. At 1330 on 11/03/99, Engineering and Operations concluded that there was no longer "reasonable expectation" of past operability. Pending the results of a full evaluation by Engineering, Duke Power decided that this was potentially a "Condition that alone could have prevented the fulfillment of the safety function...to...mitigate the consequences of an accident." Therefore, this event is considered reportable.

Impact on Postulated Accident:

The valves that were opened were #3LP-92 and #3LP-93, the train 'A' and 'B' Decay Heat Cooler Bypass Valves. As a result of the alignment, flow immediately after an accident could have been higher than expected. This could affect the available NPSH to the LPI and Reactor Building Spray (RBS) System pumps. Per the Emergency Operating Procedure, operators would have throttled the cooler outlet valves to establish the desired total flow.

Later in the scenario, the Borated Water Storage Tank inventory would be depleted and operators would realign the LPI and RBS suctions to the Reactor Building Emergency Sump. Also, Low Pressure Service Water would be aligned to the decay heat coolers to cool the sump water. With #3LP-92 and #3LP-93 open, a large portion of the LPI System flow would bypass the coolers resulting in cooling flow at higher temperatures than expected. Inadequate core cooling might result until the inappropriate alignment could be diagnosed and corrected.

Cause:

Operators were performing a periodic procedure "Tech Spec Flow Path Verification" which had recently been changed to include additional valves. They repositioned two of the newly added valves to "OPEN" as directed by the procedure. Subsequently, they questioned this action and verified from other procedures that the proper position for these valves is "CLOSED." The valves were reclosed within approximately 20 minutes.

The root cause for the inaccurate procedure change will be investigated.

Corrective action:

The proper positions of the valves were questioned, and the valves were returned to the original positions, thus ending the event.

Because the impact on operability of the affected systems was not immediately apparent, and it did not become apparent until well after the termination of the event, no Tech Spec Action Statements were entered.

The licensee notified the NRC resident inspector.

******************** UPDATE AT 1551 ON 12/08/99 FROM RANDY TODD TO LEIGH TROCINE ********************

The licensee is retracting this event notification: The following text is a portion of a facsimile received from the licensee:

"Reasoning for retraction:"

"After further review, Duke Power Company feels that this event does not meet the reportability requirements of 10CFR50.72(b)(2)(iii)(D)."

"On November 3, 1999, Unit 3 was operating at 100% power (Mode 1). At approximately 0230 hours, Reactor Operators (RO) on shift opened the Low Pressure Injection (LPI) Train 'A' and 'B' Decay Heat Cooler By-pass valves in compliance with a newly revised procedure checklist. At approximately 0250 hours on November 3, 1999, the valves were closed, which terminated the event."

"The safety function of the LPI system is to provide Emergency Core Cooling immediately following a LOCA (injection phase) and to provide long term core cooling after being placed in the Reactor Building Emergency Sump recirculation alignment (recirculation phase). It was questioned if flow through the LPI coolers would provide adequate cooling in recirculation phase with the by-pass valves open. At 1330 hours Operations and Engineering concluded that LPI system operability during the event could not be assured. At 1509 hours, the NRC was notified."

"After completion of an engineering analysis and additional review, it has been concluded that LPI system remained operable and that this event was NOT reportable."

"NUREG 1022 allows credit for 'Reasonable operator actions to correct minor problems.'"

"Oconee concluded that 1) the problem was minor, and 2) the operator actions are reasonable."

"The problem is minor in that the short duration of the inappropriate alignment (approximately 20 minutes) minimized the significance of this event."

"The problem is also minor in that the consequences are much less than initially thought."

"It was initially assumed that this alignment made the LPI system recirculation mode of core cooling unavailable. With recirculation mode cooling assumed to be unavailable, the estimated change in PRA risk would be 2.9E-8, well below the precursor threshold of 1E-6. "

"Subsequently, Engineering analysis showed that the LPI system remained operable and LPI system flow rates were not affected. Adequate NPSH would be available to all ES/ECCS systems taking suction from the BWST."

"Emergency Core Cooling during the injection phase was not affected by this event."

"Post-LOCA analysis assumes that LPI coolers are not inservice until LPSW is aligned to the LPI coolers 30 minutes after the system realignment to the RBES. Furthermore, the engineering analysis for this event has shown that the LPI coolers were not needed for long-term cooling. The evaluation concluded that LPI recirculation flow though the core was adequate to keep the core covered and to transfer the decay heat from the fuel to the LPI water, which would then flow out of the reactor coolant system into the RB Emergency Sump. Therefore, core cooling would be assured."

"This mode of cooling could continue for an extended period of time. Since core cooling is adequate, the discovery and response times for this condition are not time critical."

"It is reasonably expected that the Operators, the Shift Technical Advisor, and/or Emergency Response Organization personnel would recognize any higher than expected temperatures while monitoring plant parameters. Since the operators were well aware that they had just operated these valves, it is reasonably expected that they would immediately diagnose the cause."

"Upon recognition of the problem, the operators would close the bypass valves. It is reasonably expected that this action would be successful because the valves are operated from the control room, are pneumatic, and fail closed on loss of instrument air. Since closure of either valve restores flow through one of the LPI coolers, one train would be fully restored even with a single failure."

"Other considerations were:"

"Even if the operator action were to be delayed, the analysis showed that the heat load would be transferred from the sump to the containment atmosphere. An analysis showed that two Reactor Building Cooling Units (RBCU) could remove the resulting heat load (allowing for single failure of one of the three RBCUs). The RBCUs are actuated by the Engineered Safeguards system as part of the Containment Cooling System."

"The transition between the injection mode and recirculation mode is performed manually by the operators. No automatic actions are involved. Therefore, the actions to restore flow through the LPI coolers are not being taken in lieu of automatic actions."

"This condition would not have had any significant impact on any actions required during an actual event that may be time critical."

"All surveillance requirements could be met while the unit was in this configuration."

The licensee notified the NRC resident inspector. The NRC operations center notified the R2DO (McAlpine).

MEDICAL MISADMINISTRATION

Only two of three I-131 pills were administered to a patient on 11/3/99. The intended dose was 200 mCi, and approximately 148 mCi were delivered. This was an ablative thyroid dose for cancer. The patient's attending physician has been notified of the error and the patient will be contacted as soon as possible. The reason for the error was that two pills came in one vial and only one of those pills was removed and given to the patient. The other pill remained in the vial and was discovered today 11/8/99, at 1300 PST.

The patient will be monitored and treated as necessary.