Event Notification Report for May 28, 2021

EN Revision Imported Date: 8/9/2021

EN Revision Text: AGREEMENT STATE REPORT - POTENTIAL OVEREXPOSURE TO RADIOGRAPHER

The following was received from the Texas Department of State Health Services via email:

"On May 30, 2021, at approximately [1500] CDT one of the licensee's radiographers reported to the radiation safety officer that on May 28, 2021, he had handled a collimator while the source was in it. The radiographer was using a SPEC 150 camera with a 22 curie Iridium-192 source. The radiographer had taken a shot on top of a 2-inch pipe on a pipe stand. He then set up for the next shot by taking hold of the collimator (back, shielded side) and slid it down to the side of the pipe (90 degree). The beam was always facing the pipe. When he walked back to the camera to crank out the source, he found he had not cranked it back in after the first shot. The radiographer was not wearing an alarming rate meter, a pocket dosimeter, or a dosimetry badge, and he was not carrying/using a survey meter at the time of the incident. The licensee's initial, rough calculations indicate the dose will be lower than the reporting criteria used for this report, but until they can get more information, this report is being made as an immediate report. The radiographer was seen by a physician today and the licensee reported white blood cell counts were normal. The licensee is investigating the event and also why the radiographer did not report the incident when it occurred. More information will be provided as it is obtained in accordance with SA-300."

Texas Incident number not assigned as of the time of the report.


* * * RETRACTION ON 7/9/21 AT 0809 EDT FROM ART TUCKER TO KERBY SCALES * * *

The following was received from the Texas Department of State Health Services (the Agency) via email:

"On May 30, 2021, the Agency was informed by the licensee that on May 30, 2021, at approximately [1500] CDT one of the licensee's radiographers reported to the radiation safety officer that on May 28, 2021, he had handled a collimator while the source was in it. The radiographer was using a SPEC 150 camera with a 22 Curie Iridium-192 source. The radiographer had taken a shot on top of a 2-inch pipe on a pipe stand. He then set up for the next shot by taking hold of the collimator (back, shielded side) and slid it down to side of the pipe (90 degree). The beam was always facing the pipe. When he walked back to the camera to crank out the source, he found he had not cranked it back in after the first shot. The radiographer was not wearing an alarming rate meter, a pocket dosimeter, or a dosimetry badge, and he was not carrying/using a survey meter at the time of the incident. The licensee conducted a reenactment of the radiographer's actions on June 1, 2021. The Agency conducted an on-line meeting with the licensee on June 16, 2021 and reviewed the video. Using the reenactment and the National Council on Radiation Protection (NCRP) 41 table 6, it was determined that the exposure to the radiographer's fingers was 31.28 Rem (exposed for 2 seconds) and to the remainder of his hand was 7.629 Rem (exposed for 6 seconds collimator 4.25 half-layer values (HLVS)). The whole-body dose was 124.68 milliRem. No exposure limits were exceeded."

Texas Incident Number: 9853

Notified R4DO (Warnick), NMSS Events and DIR MSST (Williams) via email.

EN Revision Imported Date: 10/22/2021

EN Revision Text: PART 21 REPORT - VACUUM BREAKERS FAILURE TO CLOSE

The following is a summary of the report provided by Framatome Inc.:

Identification of Component: Siemens 5kV 1200A Vacuum Breakers - 5-DPU-350-1200-78

Nature of Defect:
Framtome reported during dedication testing / inspection that a batch of 5-DPU-350-1200-78 MV vacuum breakers exhibited sporadic failure to close upon both electrical and mechanical closure signals. This was entered in their Corrective Action Program and troubleshooting / testing was completed at the Siemens manufacturing facility. Using a high speed camera to troubleshoot, they determined the close latch does not have sufficient torsional force to consistently maintain the breaker close latch in the closed position during the closing cycle. In some instances the breaker will receive a close signal and the close latch will not maintain the breaker in a closed position and the breaker will fail to close. It has been observed in testing that this condition is sporadic and that subsequent attempts to close the breaker will result in a closed breaker. The issue has no impact on the breakers staying closed once they have successfully closed. The issue has no impact on the ability for the breakers to open.

Number and Location of Basic Components:
The reportable defect is similar to design on the 22 breakers delivered and 19 installed at St. Lucie Unit 1, during refueling cycle 30. St. Lucie was notified on May 28, 2021 by Framatome Inc. via telephone and email.

Corrective Actions to Date:
Preliminary evaluation determined a modification of the breakers is required to increase the torsion spring force acting on the close latch. Framatome is working with Siemens to develop a long-term solution to increase the torsional spring force acting on the close latch. An interim solution utilizing a revised spring retaining bracket could be deployed near-term.

Gayle Elliott
Deputy Director, Licensing & Regulatory Affairs
Framatome Inc.
3315 Old Forest Road
Lynchburg, Va. 24501
Office (434-832-3347)
Mobile (434-841-0306)

* * * UPDATE FROM GAYLE ELLIOT TO HOWIE CROUCH AT 1538 EDT ON 9/23/21 * * *

The following information was received from Framatome via email:

"The preliminary evaluation determined a modification of the breakers was required to increase the torsion spring force acting on the close latch. Framatome worked with Siemens to develop an interim and long-term solution. The interim solution utilized a revised spring retaining bracket that could be deployed near-term. The original long-term solution was a new torsion spring design which applied approximately 40 percent more torsional force on the trip latch.

"Following a reoccurrence of the failure-to-close issue, Framatome and Siemens identified the root cause of the trip latch bounce and [determined] the associated corrective actions. The solution developed will mitigate all main failure to close causes (low power to the closing mechanism, insufficient time for the trip latch to drop, and improper trip latch to jackshaft interaction) for the 5kV replacement circuit breakers. The solution consists of the following:
1) Circuit breakers comply with the following revised design performance parameters:
a. Jackshaft rotational speed (C speed #2)
b. Jackshaft overtravel
c. Jackshaft overtravel duration
2) Circuit breakers have the new torsion spring installed
3) Circuit breakers meet the revised bump stop gap

"By increasing the bump stop gap, the jackshaft is now able to rotate further before it hits the bump stop. This reduces the amount of force transferred to the bump stop and in turn the operating mechanism. This reduction significantly reduces the amount of latch bounce for this breaker design.

"St. Lucie was first notified of this 10CFR21 reportable defect on May 28, 2021 by Framatome Inc. via telephone and email."

Notified R2DO (Miller) and Part 21 group via email.