NHK public broadcasting in Japan reports that steel beams and a concrete wall will be installed by the end of this month in a desparate attempt to support a wall of the Fukushima Daiichi Unit 4 high-level radioactive waste storage pool at risk of catastrophic failure. A large hydgrogen gas explosion at Unit 4 on March 15th -- and a second, even larger hydrogen gas explosion at Unit 3 -- has so damaged the Unit 4 reactor building that it is listing to one side, threatening to collapse its high-level radioactive waste storage pool within. If the pool were to suddenly lose its cooling water supply, the high-level radioactive waste within could catch on fire within hours. A collapse could also jam irradiated nuclear fuel close together, sparking a nuclear chain reaction if the fuel remains immersed in enough neutron-moderating water cover. The Nuclear Regulatory Commission reported in 2001 that a high-level radioactive waste storage pool fire in the U.S. could kill more than 25,000 people downwind, at distances as far away as 500 miles. Given the Fukushima Daiichi Unit 4 pool's location outside of primary containment, all releases will escape directly into the environment, especially considering the secondary containment reactor building was largely destroyed by the large hydrogen gas explosion.