According to NHK, Tohoku Electric, which is based in Sendai and is the fourth-largest electric utility in Japan by revenue, plans to increase its defense in depth at its nuclear plants. Specifically it intends to prepare for scenarios where both off-site and backup generator power are lost, as happened at Fukushima Daiichi.
Tohoku plans to deploy generator trucks as a source of power in case both off-site and emergency power sources fail. It also said that it will deploy backup motors for the possible breakdown of reactor cooling pumps. Tohoku will conduct training on a regular basis with scenarios that require generator trucks to restore power and fire engines to inject water into storage pools for spent nuclear fuel.