nuclear-news

Fukushima Unit 2 Muon Scan Inconclusive

TEPCO and IRID released a set of reports on the muon scan of unit 2, as a follow up report to the June preliminary scan results.

Tepco makes an assertion in the new report that the majority of the melted fuel is present in the bottom of the reactor pressure vessel but that assertion is quite questionable upon further review of the reports.

To justify the assertion that most of the fuel is in the bottom of the RPV, Tepco uses a close view of the actual scan output. Viewed without the wider view it seems there must be some fuel in the bottom of the RPV and there probably is.

When you look at the same image with the entire scan view, the black area inside the RPV becomes less conclusive. This black band reaches far beyond containment and matches an area of interference documented on the earlier reviews of the scans.

TEPCO also goes on to make an estimate of fuel volume in the lower portion of the RPV based on these questionable images. They do not provide any justification for how they take the black spots in the image of the lower RPV and translate that to tons of melted materials and fuel.

Existing meltdown literature and findings expect some amount of fuel residue to exist in the bottom of the RPV even if the bottom of the RPV fails.

Both scans of unit 2′s vessel showed little remaining in the core region.

At this point the scans are inconclusive either way on the question of fuel in the bottom of the RPV.

Sources:

http://mainichi.jp/english/articles/20160729/p2g/00m/0dm/022000c

http://www.asahi.com/ajw/articles/AJ201607290050.html

http://www.fukuleaks.org/web/?p=15637

https://youtu.be/tswvsQ8Zc7M

July 29, 2016 - Posted by dunrenard | Fukushima 2016 | Fuel, Fukushima Daiichi, Muon Scan, reactor 2