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Event Notification Report for June 25, 2020

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
6/24/2020 - 6/25/2020

** EVENT NUMBERS **


54747 54756

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Agreement State Event Number: 54747
Rep Org: OHIO BUREAU OF RADIATION PROTECTION
Licensee: Cohen Brothers
Region: 3
City: Middletown   State: OH
County:
License #:
Agreement: Y
Docket:
NRC Notified By: Michael Snee
HQ OPS Officer: Bethany Cecere
Notification Date: 06/17/2020
Notification Time: 10:57 [ET]
Event Date: 06/15/2020
Event Time: 00:00 [EDT]
Last Update Date: 06/17/2020
Emergency Class: Non Emergency
10 CFR Section:
Agreement State
Person (Organization):
KENNETH RIEMER (R3DO)
DONNA JANDA (R1DO)
ILTAB (EMAIL)
NMSS_EVENTS_NOTIFICATION (EMAIL)
This material event contains a "Less than Cat 3" level of radioactive material.

Event Text

AGREEMENT STATE REPORT - FOUND NUCLEAR GAUGE IN SCRAP YARD

The following was received by email from the state of Ohio:

"The Bureau received a call on June 15 to report that a company working under reciprocity, Chase Environmental [license number 00004KY2001, Louisville, KY], had discovered a gauging device containing a Cs-137 source at the Cohen Brothers scrap yard in Middletown, Ohio. Chase Environmental packaged the gauge and took possession of the gauge for ultimate disposal.

"The shutter on the gauge appeared to be stuck open or non-existent. Dose rates of 407 mR/hr on contact with the area where the shutter should be, and 23.5 mR/hr at 1 foot were measured. No loose contamination was detected. No scrap yard personnel were exposed. The Cs-137 source is estimated at 6 mCi. No identifying information was visible on the gauge.

"A representative of the scrap yard said that they were cleaning up a section of the yard and a load of dirt with the gauge alarmed their radiation monitors on the way out. He said that this device could have been there for 10+ years. The origin of the gauge is unknown.

"The Bureau performed a survey of the scrap yard on June 16 with no other radioactive material detected."

Ohio Item Number: OH200003
Ohio Reference Number: OH 2020-024

THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf

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Part 21 Event Number: 54756
Rep Org: GE HITACHI NUCLEAR ENERGY
Licensee: Global Nuclear Fuel-Americas
Region: 1
City: Wilmington   State: NC
County:
License #:
Agreement: Y
Docket:
NRC Notified By: Michelle Catts
HQ OPS Officer: Bethany Cecere
Notification Date: 06/24/2020
Notification Time: 13:00 [ET]
Event Date: 04/28/2020
Event Time: 00:00 [EDT]
Last Update Date: 06/24/2020
Emergency Class: Non Emergency
10 CFR Section:
21.21(d)(3)(i) - Defects And Noncompliance
Person (Organization):
MARK MILLER (R2DO)
STEVE ORTH (R3DO)
JEFFREY JOSEY (R4DO)
- PART 21/50.55 REACTORS (EMAIL)

Event Text

PART 21 REPORT - NON-CONSERVATIVE BWR/6 SIDE ENTRY ORIFICE LOSS COEFFICIENTS

The following is a summary of information received from GE Hitachi Nuclear Energy:

For core monitoring, Global Nuclear Fuel-Americas (GNF) applies different hydraulic loss coefficients to BWR/6 fuel bundles as a function of location. The Side Entry Orifice (SEO) loss coefficient varies in BWR/6 plants, depending on the orientation of the SEO relative to intersecting core support beams. The SEO loss coefficient for some bundle locations are under predicted, which results in a local over prediction of Minimum Critical Power Ratio (MCPR) margin. Specifically, the SEO loss coefficients for fuel bundle locations adjacent to Intermediate and Source Range Monitor (IRM/SRM) locations should be higher than the current "one beam" values that are applied. The MCPR effect on affected bundles under conditions where they are near limits can reduce margin by 0.02 in CPR. The condition is not a substantial safety hazard, but the MCPR effect is above the threshold that GNF applies for reportability.

GNF has completed its evaluation and concluded that this issue is a reportable condition under 10 CFR 21.21(d). The basis for reportability is that the change in MCPR associated with this issue could contribute to the exceeding of a safety limit, as defined in the technical specifications of a license for operation issued under 10 CFR Part 50.

US BWR Potentially Affected Plants:
Grand Gulf, River Bend, Clinton, and Perry.

There are currently no US ABWR plants in operation that would potentially be affected by this evaluation. The potential error in the core monitoring system does not affect the NRC certified design of the ABWR or the GEH ABWR design certification renewal application currently under review. The unique core support structure design of the BWR6 and ABWR is not shared by earlier BWR plants or the ESBWR.

Affected plants should review the following paragraph and contact their GNF account representative for schedule and delivery dates for updated core monitoring databanks. Updated core monitoring databanks for the affected BWR/6 plants are scheduled to be completed by July 10, 2020.

For affected plants that use GNF core monitoring software, the long-term corrective action is to implement an updated core monitoring databank with corrected SEO loss coefficient values. Affected plants should contact their GNF account representative for schedule and delivery dates. If necessary, a short-term corrective action such as an administrative MCPR penalty on IRM/SRM locations, should be applied to the core monitoring system. An effective short-term measure would be to assure that IRM/SRM locations are 0.02 less than the Maximum Fraction of Limiting CPR limit (e.g., MFLCPRlimit = 1.00). This condition is met if the core wide MFLCPR is 0.02 below the limit (e.g., MFLCPR < 0.98), because the IRM/SRM locations will be bounded. Note that this recommended short term or interim measure was developed on a standalone basis and does not supplant any existing MFLCPR limit reductions established for other purposes.

For non-affected plants, there are no recommended actions. GNF recognizes that other non-GNF fueled plants, safety analysis methodologies, and core monitoring systems may have different design bases and address SEO losses by other means.

For more information, please contact:
Michelle Catts
GE Hitachi Nuclear Energy
Safety Evaluation Program Manager
3901 Castle Hayne Road, Wilmington, NC 28401
Michelle.Catts@GE.com
(910) 200-9836


Page Last Reviewed/Updated Thursday, June 25, 2020
Thursday, June 25, 2020