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Event Notification Report for June 14, 2017

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
06/13/2017 - 06/14/2017

** EVENT NUMBERS **


52701 52789

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!!!!! THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor Event Number: 52701
Facility: DAVIS BESSE
Region: 3 State: OH
Unit: [1] [ ] [ ]
RX Type: [1] B&W-R-LP
NRC Notified By: ERIC HORVATH
HQ OPS Officer: STEVE SANDIN
Notification Date: 04/21/2017
Notification Time: 07:33 [ET]
Event Date: 04/21/2017
Event Time: 02:02 [EDT]
Last Update Date: 06/13/2017
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(A) - POT UNABLE TO SAFE SD
50.72(b)(3)(v)(B) - POT RHR INOP
50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Person (Organization):
LAURA KOZAK (R3DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N Y 100 Power Operation 100 Power Operation

Event Text

HIGH SWITCHYARD VOLTAGE RENDERS BOTH OFFSITE CIRCUITS INOPERABLE

"On 4/21/17, high grid voltage conditions were experienced, resulting in voltages higher than those established for operability of the offsite circuits. Grid voltages have been observed at approximately 355.8 kV on the nominal 345 kV system. As a result, both qualified circuits between the offsite transmission network and the onsite Class 1E AC Electrical Power Distribution System were declared inoperable at 0202 hours [EDT]. Main generator voltage control has been lowered to the minimum possible excitation with the unit operating at 100 percent power.

"The inoperability of both offsite circuits results in a loss of safety function in accordance with NRC reporting guidance. The voltage of the onsite Essential busses remains within acceptable values, and both Emergency Diesel Generators are operable. At 0715 [EDT] on 4/21/17, grid voltage has returned to an acceptable value and the equipment was declared operable.

"The NRC Resident Inspector has been notified."

* * * RETRACTION FROM ANDREW MILLER TO VINCENT KLCO ON 6/13/17 AT 1128 EDT * * *

"Following the reporting of high switchyard voltage on 4/21/17, the licensee-established voltage limits were re-evaluated. The new high voltage limit has been established at 362.94 kV on the nominal 345 kV system, or 105.2 percent of nominal voltage, as compared to the previous maximum grid voltage of 103.3 percent. This new limit is above the 355.8 kV experienced on 4/21/17. Therefore, the equipment remained operable and no loss of safety function existed for the qualified circuits between the offsite transmission network and the onsite Class 1E AC electrical power distribution system, and the notification made per 10 CFR 50.72(b)(3)(v)(A-D) is being retracted.

"An evaluation of the past three years of switchyard voltage data was also performed, and it was concluded the AC power system and its connected safety-related equipment remained capable of performing its required safety functions during the three-year evaluation period.

"The NRC Resident Inspector has been briefed on the evaluation results and informed of this retraction."

Notified the R3DO (Stone).

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Agreement State Event Number: 52789
Rep Org: SC DIV OF HEALTH & ENV CONTROL
Licensee: MEAD & HUNT, INC.
Region: 1
City: LEXINGTON State: SC
County:
License #: 840
Agreement: Y
Docket:
NRC Notified By: ANDREW M. ROXBURGH
HQ OPS Officer: STEVE SANDIN
Notification Date: 06/06/2017
Notification Time: 07:34 [ET]
Event Date: 06/05/2017
Event Time: 16:30 [EDT]
Last Update Date: 06/06/2017
Emergency Class: NON EMERGENCY
10 CFR Section:
AGREEMENT STATE
Person (Organization):
BLAKE WELLING (R1DO)
NMSS_EVENTS_NOTIFICA (EMAI)

Event Text

AGREEMENT STATE REPORT - TROXLER DENSITY GAUGE DAMAGED AT JOBSITE

The following information was provided by the State of South Carolina via email:

"Event Location: Highway 51 South of Pamplico, SC

"Event Type: Damaged gauge

"Event Description: At approximately 4:30 PM on June 5, 2017, the Department [South Carolina Department of Health and Environmental Control] was notified by [a representative] of Mead & Hunt, Inc. that it had a density gauge damaged by a trachoe while at a jobsite on Highway 51 South of Pamplico, SC. The on-call duty officer responded to the scene around 7:30 PM and met [the representative]. Upon arriving at the scene, the duty officer observed that the area around the gauge had been properly roped off. The duty officer and [the representative] approached the gauge with survey meter to identify the level of damage. The gauge was a Troxler 3440 containing 8 millicuries of Cs-137. A radiation readings of 12-16 mR/hr on the surfaces of the gauge were observed and found to be within the normal radiation profile for this gauge. The handle of the gauge was broken off causing the gauge to not properly function. The source shutter was found to be completely in the shielded position. The gauge was returned to the licensee's office in Lexington, SC.

"A follow-up inspection of the gauge at the licensee's facility in Lexington, SC will be conducted on June 6, 2017."

Page Last Reviewed/Updated Wednesday, June 14, 2017
Wednesday, June 14, 2017