Event Notification Report for September 17, 2002

HEAT BALANCE CALCULATION ERROR ON REACTOR POWER

"The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.

"Palo Verde Nuclear Generating Station Units 1, 2, and 3 are evaluating the potential that the Maximum Power Level of 3876 megawatts thermal (100% power), specified in Operating License Condition 2.C(1) may have been exceeded in the past due to an unconservative value of reactor coolant pump (RCP) heat in the secondary calorimetric calculation since initial plant operation. The value of total energy input due to RCP operation used in the calorimetric is 29.53 megawatts (MW) in Unit 1, 29.61 MW in Unit 2 and 31.88 MW In Unit 3. Conservative engineering calculation of actual RCP heat input based on electrical load is as low as 24.72 MW. Similarly, conservative engineering calculation of actual RCP heat input based on fluid power (pump differential pressure) is as low as 22.86 MW. Thus, the calorimetric error may be as large as (31.88-22.86) 9.02 MW or approximately 0.23%.

"The error could have resulted in core power levels above the Operating License limit of 3876 MW thermal. Due to current operating limitations on reactor coolant system hot leg temperature, none of the Palo Verde units are presently exceeding the licensed power limit. Unit 1 is at approximately 99% power (3837 MW thermal, 39 MW margin). Unit 2 is at approximately 98% power (3798 MW thermal, 78 MW margin). Unit 3 is at approximately 99.6% power (3861 MW thermal, 15 MW margin)

"This report is being made because a review of historical operating data may reveal that the Maximum Power Level was exceeded.

"The Palo Verde safety analyses bound a power level of 102%, thus the Units remain within the safety analyses. As a compensatory measure, the station has established an administrative limit of 99.75% power pending resolution of this issue.

"No ESF actuations occurred and none were required. There were no structures, systems, or components that were inoperable at the time of discovery that contributed to this condition. There were no failures that rendered a train of a safety system inoperable and no failures of components with multiple functions were involved. The event did not result in the release of radioactivity to the environment and did not adversely affect the safe operation of the plant or health and safety of the public."

The NRC Resident Inspector has been notified.

* * * RETRACTION FROM DANIEL HAUTALA ON OCTOBER 10, 2002 AT 1534 EDT TO MIKE RIPLEY * * *

"The following event description is based on information currently available. If through subsequent reviews or this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.

"This notification is a retraction to the September 17, 2002, ENS #39199 which reported a calorimetric input error that could have resulted in core power levels above the Operating License limit of 3876 MW thermal at Palo Verde Nuclear Generating Station Units 1, 2, and 3. Further evaluation of the calorimetric power calculation indicated the installed values were conservative and no correction is required.

"The NRC Resident Inspector has been notified."

Notified R4 DO (William Jones)

AGREEMENT STATE REPORT INVOLVING A LOST AND FOUND MOISTURE DENSITY GAUGE

"The department was contacted on 9/18/02 by SCI Engineering, Inc., regarding an event that happened around 4:00 p.m. the previous day. He reported that one of their drivers noticed when he looked in his rear view mirror after rounding a curve approximately 2 miles from the SCI office, that the Humboldt Model 5001 moisture/density gauge containing approximately 11 millicuries Cs-137 and 44 millicuries Am-241, was no longer in the back of his truck. He then turned around and proceeded down the road to search for the gauge. Meanwhile, an Ameritech employee in a truck was behind the SCI truck and watched the gauge fly out the back. He then stopped to get the device. Nearby was a friend of his that worked for a construction company and was familiar with nuclear gauging devices. He noted the type of the device and the serial number and called SCI to report the find. SCI had, in the interim, already sent two technicians to help look for the device after hearing of the loss from the SCI truck driver. This all occurred in approximately 10 minutes according to SCI.

"The State expressed concern to the licensee in the timeliness of the notification and the fact that a gauge was allowed to 'fly' out the back of one of their trucks. The licensee agreed and stated that a report would be filed with the department as soon as possible. The department will take appropriate measures to ensure that there will be no recurrence of this type of an event by this licensee."

REACTOR RECEIVED POOL LEVEL ALARM DUE TO LEAK FROM A DIFFUSER LINE


An unusual event occurred when the pool level alarm tripped due to the pool level going below the setpoint. This occurred due to a leak possibly on a pool diffusion system line. Approximately 10,000 gallons of water leaked into the sump and is being pumped into their liquid storage tanks. They believe the leak may be due to a faulty coupling. They isolated the leak and refilling the pool at the rate of 25gpm. There was no increase in radiation levels and the core was not uncovered (a minimum of 15' of water is above the core).


* * * UPDATE ON 09/17/2002 @ 0929 BY SPELLMAN TO GOULD * * *

The NOUE was terminated at 0820 CDT when the pool level was return to above the pool level alarm setpoint.

Notified RDO (Loveless), NRR EO(Marsh), PM (Mendonca via NRR EO), and FEMA (Duncan)

A LICENSED SUPERVISORY OPERATOR TESTED POSITIVE FOR ALCOHOL DURING A RANDOM FITNESS-FOR-DUTY TEST

The employee's access has been suspended.

The NRC Resident Inspector was notified.

Contact the HOO for additional information.