#Fukushima I Nuke Plant: Two Pinholes in the Bad Weld on ALPS Batch Treatment Tank Found, Says TEPCO

Additional information (or stating the obvious) on the leak from one of the ALPS (multi-nuclide removal system) tanks Fukushima I Nuke Plant.

From Jiji Tsushin (6/18/2013):

タンク溶接部に微細な穴＝放射能低減装置水漏れで－福島第１

Pinholes found in the weld on the tank for ALPS at Fukushima I Nuke Plant

東京電力は１８日、福島第１原発敷地内で汚染水の放射性物質を除去する「多核種除去装置（アルプス）」のタンクから、微量の汚染水が漏れた問題で、タンク下部の溶接部分に２カ所の微細な穴（ピンホール）が見つかったと発表した。同社はここから水が漏れたとみており、内部にカメラを入れ、原因調査を進める。

TEPCO announced on June 18 that two pinholes were found in the weld at the bottom of the tank used in the multi-nuclide removal system ALPS at Fukushima I Nuke Plant, where a small leak of contaminated water was found. The company thinks the water leaked from these holes, and plans to insert a camera inside the tank to further investigate the cause [of the pinholes].

東電によると、ピンホールはタンク下部の溶接したつなぎ目部分に約３０センチの間隔で開いていた。直径１ミリに満たず、通常の目視では確認できないため、色の付いた溶剤を塗る検査で判明した。

According to TEPCO, two pinholes were found at the weld, about 30 centimeters apart. They are less than 1 millimeter in diameter and couldn't be found by visual inspection. TEPCO applied colored solvent [on the weld] to find the holes.

Cause of the pinholes? Bad weld, bad inspection, I can't think of anything else.

Looking at the diagram that TEPCO provided the other day, there are total 6 Batch Treatment Tanks in ALPS, two each in the three lines. There are numerous other tanks and vessels to absorb radioactive materials, and they are all welded. I wonder if they are properly inspected - i.e. each and every one of the tanks and vessels inspected by professionals and regulatory officials, instead of copying the data of a good weld.

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