Tritium in groundwater, debris removal at unit 3 and more operational issues with the ALPS decontamination system highlighted the news from Fukushima this week.
Recent developments related to the Tokyo Electric Power Co. plant blacked out by Japan's 2011 earthquake and tsunami include:
Elevated Tritium Levels Interrupt Ground Water Pumping
Part of an operation to pump up ground water before it reaches damaged reactor buildings paused for several days after tritium levels exceeded self-imposed limits. TEPCO stopped pumping from one of 12 wells after its water revealed tritium at 1,600 becquerels per liter on April 15, the Asahi Shimbun reported. The plant recently began a program to pump, store and eventually release groundwater that meets stringent contamination limits. While the legal limit for releasing tritium into the ocean is 60,000 becquerels per liter, TEPCO resolved to release only water with less than 1,500 becquerels in an agreement with local fishermen. NHK reported that tritium levels in the well fell below that mark this week, and pumping resumed on Thursday.
Crane Removal Begins in Unit 3 SFP
TEPCO announced Wednesday that crews had begun removing wrecked fuel handling equipment from the spent fuel pool of unit 3. The work is expected to extend into June, Kyodo reported. The SFP's cooling system will only operate on weekends to protect it from oil leaks from the debris during removal.
ALPS Shut Down
The ALPS water decontamination system shut down for about a day Wednesday when crews found it was not effectively removing calcium. TEPCO officials quoted by NHK reported that human error was likely behind the interruption after operators found that a valve injecting sodium carbonate had been closed.