The Nuclear Regulatory Commission (NRC) Advisory Committee on Reactor Safeguards (ACRS) held a special ACRS meeting Thursday May 26, 2011 on the current status of Fukushima. Arnie Gundersen was invited to speak for 5 minutes concerning the lessons learned from the Fukushima accident as it pertains to the 23 Mark 1 Boiling Water Reactors (BWR's) in the US and containment integrity. Mr. Gundersen was the first engineer to brief the NRC on the implication of Main Steam Isolation Valve (MSIV) Leakage in 1974, and he has been studying containment integrity since 1972. The NRC has constantly maintained in all of its calculations and reviews that there is zero probability of a containment leaking. For more than six years, in testimony and in correspondence with the NRC, Mr. Gundersen has disputed the NRC's stand that containment systems simply do not and cannot leak. The events at Fukushima have proven that Gundersen was correct. The explosions at Fukushima show that Mark 1 containments will lose their integrity and release huge amounts of radiation, as Mr. Gundersen has been telling the NRC for many years.