Event Notification Report for May 19, 2026

LOST EXIT SIGNS

The following information was provided by the licensee via phone:

The licensee reported three exit signs, manufactured by SRB Technologies and each nominally containing 50 Ci of tritium, were lost in Indianapolis, IN. The loss was discovered during an inventory of exit signs performed on April 22, 2026.

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

AGREEMENT STATE REPORT - STOLEN MOISTURE DENSITY GAUGE

The following information was provided by the Texas Department of State Health Services (the Department) via phone and email:

"On May 11, 2026, at 1630 CDT, the Department was notified by the licensee that an InstroTek model 3500 moisture density gauge was stolen from their pickup truck. The gauge contained a 10 mCi Cs-137 source and a 40 mCi Am-241/Be source. The theft was reported to the Dallas Police Department. The source handle was secured with a lock. There is no immediate threat to the public.

"Additional information will be reported in accordance with SA 300 requirements."

Texas incident number: 10288

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

LOST MOISTURE DENSITY GAUGE

The following information was provided by the licensee via phone:

An NRC inspection of the licensee found that one of three Troxler model 3440 moisture density gauges, containing 10 mCi of Cs-137 and 40 mCi of Am-241/Be, was no longer in the licensee's possession. The licensee reported that the gauge had been sold to a company in Wisconsin approximately five years ago. No records of the sale were available. The licensee is attempting to locate additional information about the missing gauge.

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

TECHNICAL SPECIFICATION ABNORMAL OCCURRENCE

The following information was provided by the licensee via phone and email:

"On May 17, 2026, at 0457 CDT, the control room received a firemain low pressure alarm with indication reading 0 psi. The firemain provides the source of water to the emergency pool fill system as required by Technical Specification 3.9.b. At 0501 it was confirmed this was an actual firemain rupture and not just an indication. At 0502 the reactor was manually scrammed. At 0514 the ruptured firemain was discovered and isolated shortly thereafter to restore pressure. Subsequently, permission for the reactor restart was received from the facility director and the reactor was restarted at 1245.

"The 12-inch firemain was found split from fitting to fitting. The cause is still being investigated."


The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:

At the time of notification, the reactor was in the shutdown condition for normal planned maintenance.

MANUAL REACTOR SCRAM

The following information was provided by the licensee via phone and email:

"At approximately 1803 EDT on May 18, 2026, the operating crew responded to a fire below the main generator. The fire was identified on the Y-phase of the isophase ducts. At 1807, the reactor was manually scrammed, and a level 3 isolation signal was received due to the scram. The scram was non-complicated. The fire was confirmed extinguished at 1810.

"Operations responded and stabilized the plant. Reactor water level is being maintained at normal level. The lowest water level observed was approximately 139.5 inches. Decay heat is being removed by the main steam system to the main condenser using automatic operation of the turbine bypass valves. All control rods inserted into the core.

"Due to the reactor protection system actuation while critical, this event is being reported as a four-hour non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B)."