RSS feed source: International Atomic Energy Association--Nuclear & Radiological Events

Partial loss of post-trip cooling

Print View Posted on: 29 April 2024

Event Date: 15 November 2023 Event Type: Power Reactor Event Location: United Kingdom, TORNESS-2 INES Rating: 2 (Final)

The planned reactor trip triggered switching of the reactor’s eight Gas Circulators’ (GC) power supply from “nominal – 11kV” to “variable speed – 3.3kV”. The 3.3kV power supply is provided by four Variable Frequency Convertors (VFC) and four Variable Speed Drives (VSD). In this case two VFC failed to start, and one VFC and one VSD tripped shortly after starting. Reactor cool down was safely provided by the remaining four GCs for 6 hours when the two failed VFCs were brought into service, which improved cooling margins.

INES Rating: 2 – Incident (Final) as per 26 April 2024

Impact on people and the environment Release beyond authorized limits? No Overexposure of a member of the public? No Overexposure of a worker? No

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RSS feed source: International Atomic Energy Association--Nuclear & Radiological Events

Worker Exceeded Annual Extremity Dose Limit

Print View Posted on: 17 April 2024

Event Date: 22 February 2024 Event Type: Radiation Source Event Location: United States of America, Alton, IL / Alton Steel INES Rating: 2 (Final)

An employee received a dose of 0.95 Sv (95 rem) to the extremities (hands) due to improper handling and response to an incident involving a damaged 85.1 MBq (2.3 mCi) Co-60 source. This dose was estimated by the Illinois Emergency Management Agency and confirmed by the licensee. The source was initially damaged when molten steel flowed over the source housing, severing the source into at least two pieces. The smaller portion, estimated to contain approximately 2.0 MBq (53 uCi), was inadvertently withdrawn from its shielded housing, fused with solidified steel and later partially recovered by the employee. The remainder of the Co-60 source was found to have been covered in solidified steel that prevented its return to the shield. The employee used a 4-inch angle grinder in an effort to remove the solidified steel so it would fit back into the shield. Inspection findings indicate the employee used gloved hands to effect recovery

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RSS feed source: International Atomic Energy Association--Nuclear & Radiological Events

Internal contamination of a worker in a fuel pellets fabrication workshop

Print View Posted on: 07 February 2024

Event Date: 11 February 2020 Event Type: Fuel Fabrication Event Location: France, Melox – Orano Cycle – Marcoule INES Rating: 2 (Final)

The event occurred in the pelleting workshop, where mixtures of plutonium and uranium oxide powders are compacted into cylindrical pellets. These operations are carried out in glove boxes. While cleaning a glove box containing a compacting press, one of the gloves was punctured, causing atmospheric contamination of the working area. This contamination was detected by the room’s radiation monitors and the area was evacuated in accordance with the procedures in force.

One of the three people present in this room was contaminated. The CEA Marcoule medical service then took charge of this person.

Orano Cycle informed ASN of this event on 12 February, indicating that radio-toxicological analyses had been run to estimate the committed dose for this person.

These analyses, which lasted several months, show that the committed dose could exceed the annual dose limit set at 20 mSv. Therefore, on 24 June 2020, Orano Cycle reported this event as

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RSS feed source: International Atomic Energy Association--Nuclear & Radiological Events

Internal contamination of a worker in a fuel pellets fabrication workshop

Print View Posted on: 07 February 2024

Event Date: 11 February 2020 Event Type: Fuel Fabrication Event Location: France, Melox – Orano Cycle – Marcoule INES Rating: 2 (Final)

The event occurred in the pelleting workshop, where mixtures of plutonium and uranium oxide powders are compacted into cylindrical pellets. These operations are carried out in glove boxes. While cleaning a glove box containing a compacting press, one of the gloves was punctured, causing atmospheric contamination of the working area. This contamination was detected by the room’s radiation monitors and the area was evacuated in accordance with the procedures in force.

One of the three people present in this room was contaminated. The CEA Marcoule medical service then took charge of this person.

Orano Cycle informed ASN of this event on 12 February, indicating that radio-toxicological analyses had been run to estimate the committed dose for this person.

These analyses, which lasted several months, show that the committed dose could exceed the annual dose limit set at 20 mSv. Therefore, on 24 June 2020, Orano Cycle reported this event as

Click this link to continue reading the article on the source website.