nuclear-news

Rods can be removed from No. 2 reactor at Fukushima plant, Tepco says

A remotely operated underwater robot casts light over nuclear fuel rods inside the fuel pool of the No.2 reactor at the Fukushima No. 1 nuclear power plant.

Jun 11, 2020

Fukushima – Tokyo Electric Power Company Holdings Inc. (Tepco) found no obstacles Wednesday to its planned removal of radioactive fuel rods from a spent fuel pool at the Fukushima No.1 nuclear power plant, the firm has said.

Tepco confirmed the findings after starting its first internal probe of the No. 2 reactor since the 2011 disaster. The investigation is expected to continue through Friday.

Using a remotely operated underwater robot to photograph the interior of the pool, submerged fuel rods and their storage racks were checked for any damage. A total of 615 spent and unspent fuel rods are stored in the pool.

White sediment was discovered on the aluminum alloy racks. It is believed to have formed from a reaction between aluminum and elements in sea water, which was injected into the pool to cool the nuclear fuel during the disaster.

Similar sediment was found in the reactor pools at units No. 3 and No. 4, from which fuel rods have already been removed, but according to Tepco it did not affect the process.

Similar to the No. 1 and No. 3 reactors, the No. 2 reactor suffered a core meltdown after it temporarily lost its cooling function in its spent fuel pool, but there was no hydrogen explosion at the building.

Because of that, the pool is thought to be free of debris and in a relatively stable condition.

High radiation levels on the top floor of the reactor building, where the fuel rods are located, have delayed cleanup efforts.

But progress in decontamination efforts has now enabled remote inspections to be carried out.

A new facility complete with a crane and equipment to lift out the fuel rods will be built on the south side of the No. 2 nuclear reactor building. The removal process is slated to begin sometime between fiscal 2024 and 2026.

https://www.japantimes.co.jp/news/2020/06/11/national/fuel-rods-fukushima-no-2/#.XuJIOufgqUk

June 22, 2020 Posted by dunrenard | Fukushima 2020 | Fukushima Daiichi, Unit 2, Used fuel pool | Leave a comment

Tepco completes survey of Fukushima Daiichi 2 fuel pool

The ROV surveys the used fuel pool of Fukushima Daiichi unit 2 (Image: Tepco)

11 June 2020

There are no obstacles to the removal of assemblies from the used fuel storage pool of unit 2 at the damaged Fukushima Daiichi nuclear power plant, Tokyo Electric Power Company (Tepco) said today after completing an initial survey of the pool. Removal of the assemblies is scheduled to begin fiscal year 2024.

Similar to the reactors at units 1 and 3, unit 2’s reactor suffered a core meltdown after it temporarily lost its cooling functions, but the reactor building – which also houses the fuel storage pool – was spared a hydrogen explosion.

Using a submersible remotely-operated vehicle to investigate the fuel pool, Tepco concluded there was no damage to the fuel assemblies or the storage rack they are held in. It did, however, discover sand-like sediment at the bottom of the pool.

The utility said images captured during the pool’s survey will be used for designing equipment to be used in the removal of the fuel assemblies. It plans to start removing the 587 fuel assemblies from the unit’s used fuel pool between fiscal year 2024 (ending March 2025) and fiscal year 2026 (ending March 2027).

Dose levels on the operating floor of unit 2 are high, thereby making it difficult to access. Tepco has, however, already made progress with the clean-up of equipment, etc. that remains on the operating floor, providing access to the area near the storage pool.

It plans to complete the removal of all fuel assemblies from Fukushima Daiichi units 1-6 during 2031.

https://www.world-nuclear-news.org/Articles/Tepco-completes-survey-of-Fukushima-Daiichi-2-fuel

June 22, 2020 Posted by dunrenard | Fukushima 2020 | Fukushima Daiichi, Unit 2, Used fuel pool | Leave a comment