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Event Notification Report for September 25, 2014

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
09/24/2014 - 09/25/2014

** EVENT NUMBERS **


50334 50461 50487 50492

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!!!!! THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor Event Number: 50334
Facility: DIABLO CANYON
Region: 4 State: CA
Unit: [1] [2] [ ]
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: WES FIANT
HQ OPS Officer: DONALD NORWOOD
Notification Date: 07/31/2014
Notification Time: 23:49 [ET]
Event Date: 07/31/2014
Event Time: 17:29 [PDT]
Last Update Date: 09/24/2014
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
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
Person (Organization):
NEIL OKEEFE (R4DO)

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

Event Text

UNANALYZED CONDITION

"On 07/31/2014 at 1729 PDT, Diablo Canyon Power Plant (DCPP) identified an unanalyzed condition involving the three class 1E 4160 volt buses on Unit 1 and on Unit 2. Following a postulated main steam line High Energy Line Break (HELB) in the Turbine Building, steam could enter the 4160 volt bus rooms through ventilation ducts that exhaust to the turbine deck where the steam lines are located. New analysis identified that the relative humidity (RH) of the 4160 volt bus rooms could reach 100%, which exceeds the design RH used in the analyses for the protective devices in the room. The high-humidity could possibly prevent the protective devices from operating as intended and could therefore result in the unavailability of the 4160 volt buses to supply power to engineered safety feature systems.

"This concern is being reported as an unanalyzed condition per 10 CFR 50.72(b)(3)(ii)(B) and as a condition that could have prevented fulfillment of a safety function per 10 CFR 50.72(b)(3)(v).

"Compensatory measures were taken to isolate the ventilation ducts between the 4160 volt bus rooms and the turbine deck, thereby preventing steam entry into the 4160 volt bus rooms, assuring the protective devices would not be subjected to conditions exceeding the design RH. With this compensatory measure all three 4160 buses on each unit are assured of performing their expected design function following the postulated main steam line break.

"This concern did not result in any adverse affect on the health and safety of the public.

"The licensee informed the NRC Resident Inspector."

In addition to the 10 CFR sections listed in the header of this event notification, the licensee is also reporting this under 10 CFR 50.72(b)(3)(v)(D).

* * * RETRACTION RECEIVED FROM BOB KLINE TO JOHN SHOEMAKER AT 1839 EDT ON 09/24/14 * * *

"Diablo Canyon Power Plant is retracting this event notification based on the following:

"Subsequent to the identification of this event, PG&E conducted additional analysis and testing to support a past operability evaluation. Testing and analysis was completed successfully, demonstrating that the full population of associated components would perform their design safety function in 100% relative humidity conditions during a postulated high energy line break.

"Based on these analysis and testing results, PG&E concludes that the associated equipment remained operable, and did not represent an unanalyzed condition per 10 CFR 50.72(b)(3)(ii)(B) or a condition that could have prevented fulfillment of a safety function per 10 CFR 50.72(b)(3)(v). Therefore, PG&E retracts its notification of 7/31/2014.

"The licensee has notified the NRC Resident Inspector."

Notified the R4DO (Drake).

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Non-Agreement State Event Number: 50461
Rep Org: DOWL HKM
Licensee: DOWL HKM
Region: 4
City: BILLINGS State: MT
County:
License #: 25-17492-01
Agreement: N
Docket:
NRC Notified By: MICHAEL NEZWORSKI
HQ OPS Officer: JOHN SHOEMAKER
Notification Date: 09/16/2014
Notification Time: 14:13 [ET]
Event Date: 09/16/2014
Event Time: [MDT]
Last Update Date: 09/16/2014
Emergency Class: NON EMERGENCY
10 CFR Section:
30.50(b)(2) - SAFETY EQUIPMENT FAILURE
Person (Organization):
MICHAEL VASQUEZ (R4DO)
FSME EVENTS RESOURCE (EMAI)

Event Text

TROXLER MOISTURE/DENSITY GAUGE DAMAGED ON CONSTRUCTION SITE

The licensee [Dowl HKM] Radiation Safety Officer (RSO) reported that a Model 34/40 Troxler Moisture/Density Gauge, containing 8 mCi Cs-137 and 40 mCi Am/Be sources, was damaged at a construction site near Evanston, Wyoming. A roller inadvertently backed over the gauge, however the sources are intact and in the stored position. There is no indication of contamination or exposure to personnel. The gauge has been returned to the appropriate storage container and the container has been locked. The storage container has been placed in the back of a pickup truck and the truck has been parked in a roped off area to minimize the possibility of exposure. The licensee RSO has been dispatched and will provide additional details as they are acquired.

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Power Reactor Event Number: 50487
Facility: PRAIRIE ISLAND
Region: 3 State: MN
Unit: [ ] [2] [ ]
RX Type: [1] W-2-LP,[2] W-2-LP
NRC Notified By: DARRELL LAPCINSKI
HQ OPS Officer: DANIEL MILLS
Notification Date: 09/24/2014
Notification Time: 08:41 [ET]
Event Date: 09/24/2014
Event Time: 07:28 [CDT]
Last Update Date: 09/24/2014
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
Person (Organization):
NICK VALOS (R3DO)

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

Event Text

SHIELD BUILDING VENT GAS RADIATION MONITOR OUT OF SERVICE FOR PLANNED MAINTENANCE

"At 0728 CDT on 9/24/2014, 2R-22 Shield Building Vent Gas Radiation Monitor was removed from service for planned maintenance. This monitor has no compensatory measure that will allow timely classification of two Emergency Action Levels (EALs) - NUE (Notification of Unusual Event) and Alert classifications - when out of service. It is also used for offsite dose projection calculations. This results in a Loss of Emergency Assessment Capability while 2R-22 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii).

"Unit 2 Shield Building Ventilation Stack is also monitored by high range monitor, 2R-50, which is used for the same purpose in Site Area or General Emergency classifications. 2R-50 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidenced by normal readings on 2R-22 prior to its removal from service. The duration of this maintenance is scheduled for 1 hour and will continue until the monitor is returned to service. Maintenance will not result in the unplanned release of radioactivity to the environment and will not adversely affect the safe operation of the plant or health and safety of the public.

"The licensee has notified the NRC Resident Inspector."

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Power Reactor Event Number: 50492
Facility: PRAIRIE ISLAND
Region: 3 State: MN
Unit: [1] [ ] [ ]
RX Type: [1] W-2-LP,[2] W-2-LP
NRC Notified By: STEVE INGALLS
HQ OPS Officer: DANIEL MILLS
Notification Date: 09/25/2014
Notification Time: 00:04 [ET]
Event Date: 09/24/2014
Event Time: 15:33 [CDT]
Last Update Date: 09/25/2014
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Person (Organization):
NICK VALOS (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

UNIT 1 TRAIN B RVLIS AND ICCM INOPERABLE DUE TO DATA ERRORS

"At 1533 CDT on September 24, during a Past Operability review for the Unit 1 Train B Inadequate Core Cooling Monitor (ICCM), it was discovered that due to data errors, the as left VDC [voltage DC] value for the Remote Display Power Supply was outside of acceptance criteria during the last performance of SP 1213B 'Inadequate Core Cooling Monitor Calibration,' completed on 8/25/2014. The Reactor Vessel Level Instrumentation System (RVLIS) and the Core Exit Thermocouples (CETs) are subsystems of the ICCM System and were determined to be inoperable during this timeframe. Therefore Tech Spec 3.3.3 Condition A for Train B RVLIS and Tech Spec 3.3.3 Condition B for CETs were not met. Also during this time, Unit 1 Train A ICCM was out of service from 1110 [CDT] on 9/8/2014 to 1530 [CDT] on 9/12/2014 for calibration. Thus, both trains of Core Exit Thermocouples and RVLIS were inoperable during this 4 day, 4 hour and 20 minute time period.

"ICCM System indication is used for Safety Injection Termination and Reinitiation criteria in the Emergency Operating Procedures (EOPs). During the time when both trains of ICCM were inoperable, B Train remained in service and was thought to be operable. This provided the potential for operators to perform an untimely SI Termination or Reinitiation during an accident based on inaccurate information. The Emergency Response Computer System was available to provide accurate backup information to the operators and for timely Emergency Action Limit classification

"This is reportable under 10 CFR 50.72 (b)(3)(v)(D), Event or Condition that Could Have Prevented Fulfillment of a Safety Function to Mitigate the Consequences of an Accident.

"Based on new information currently being received from Westinghouse, the ICCM Remote Display Power Supply only functions to communicate data to the display and has no effect on the data values. Thus the ICCM System may have been functioning properly. An update to this information will be provided once it is available

"The protection of the health and safety of the public was not affected by this issue.

"The Unit 1 Train B ICCM System was returned to operable status at 2300 [CDT] on 9/24/2014.

"The license has notified the NRC Senior Resident Inspector."

Page Last Reviewed/Updated Thursday, September 25, 2014
Thursday, September 25, 2014