GE-Hitachi nuclear energy reactor design clarification

G E - nuclear energy design clarification

In wake of Japanese nuclear emergency spawned by two week’s back  earth quake and tsunami, questions  are being raised about design of General Electric nuclear reactor known as Mark 1. Nuclear opponents have criticized that Mark 1 as inferior to other reactor designs,U.S.A. reported saying that its containment systems are smaller and more vulnerable to rupturing  under high pressure. The Mark 1 design was used at five of the six nuclear reactor located at Japan’s troubled Fukushima Daiichi plant.

According to an ABC news report, 35 years ago three nuclear scientists went so far to resign from their positions at General  Electric because of their concern over Mark 1 nuclear reactor design.

“ The problem we identified in 1975 were that, in doing the design of the containment, they did not take into account the dynamic loads that could be experienced with loss of coolant “ Dale G. Bridenbaugh told ABC news in an interview . “The impact loads the containment would receive by this very rapid release of energy could tear containment apart and create an uncontrolled release”

However Bridenbaugh went on to tell ABC news that he believe the design flaws that prompted his resignation from GE eventually addressed at Japan’s Fukushima Daiichi plant, and added that GE agreed to a series retrofits at Mark 1 reactor around globe. How effective such retrofitting might have been in question though, with Bridenbaugh admitting that “ the Mark 1 still little more susceptible  to an accident that would result in a loss of containment.

Over the years, others have also expressed concerned over Mark 1 nuclear reactor design. According to U.S.A Today  report , U.S. Atomic Energy Commission official Stephen Hanauer  said in 1972 memo that  the type of system used in Mark 1 was vulnerable and should be discontinued . According ABC News  in 1986, Harold Denton than director of the nuclear regulatory commission  office of nuclear reactor regularity raised doubts saying he did not “ have the same worry feeling about  GE containment that  I do  about larger dry containment's “ 

General Electric for its parts , insists Mark 1 nuclear design is safe. In a statement To U.S.A Today the company the company said Mark 1 is an industry work horse with proven safety record for more than 40 years.

According to New York Times, 23 reactors at 16 locations in U.S. use Mark design including the Oyster Creek Plant in central New Jersey, the Dresden plant near Chicago and the Monticello plant Minneapolis. These reactors have undergone a variety of modifications since initial concern were raised the Times said.

GE SETTING THE RECORD STRAIGHT ON MARK 1 CONTAINMENT HISTORY

Recent several news stories have reported that the design of Mark 1 containment system in  nuclear reactors at Fukushima Daiichi power plant has history of problems. As several speculations contained in three stories GE would like to set the record straight. We believe it is too early to know specially what had happened in each of reactors at Fakushima Daiichi . GE committed to participating in research for facts. However   we can address ( GE) the 40 years history of technology and its performance.

Claim : The Mark 1 reactor is less “ physically robust” than competing pressurized water reactors.

GE s  view : the Mark 1 meets all regularity requirements and has performed well over 40 years. Difference in the primary containment systems used in different reactor designs including differences’ in the size of containment vessel-are largely function of different operating characteristic of those designs. For example GE’s containment systems utilize pressure suppression technology, where a pool of water available to condensate steam in the event of an accident and reduce pressure on containment vessel. Units are built to with stand predicted peak containment pressures based upon their design under accident guidelines.

Claim : The Mark 1 should have been discontinued based on statement made in 1972 by Stephen Hanauer  an Atomic Energy Commission   officials who said that its smaller containment vessel design was more susceptible to explosion and rupture from a build up of hydrogen.

General Electric view : In 1980 the NRC advised that it had  given careful consideration to concern raised by Mr.Hanauer s 1972 memorandum about Mark 1  and that “ the staff, including Dr.Hanauer has concluded that pressure suppression concept for containment design is safe.

Claim : The Mark 1 was cheaper and easier to build -in part because GE used comparatively smaller and less expensive containment structure,

Fact claimed by GE :  Because of pressure suppression capability designed onto the Mark 1, GE are able to have smaller containment design. The pressure suppression technology enable the Mark 1 to reduce the pressure in the containment vessel by condensing the steam in suppression  pool. Safety remained our priority and Mark 1 design meet all NRC design criteria

Claim : Modification made to Mark 1 over the fast decades were driven by threats of law suits from utilities over alleged flaws in the system

Fact and GE view : the Mark 1 containment designs were modified in1980’s  to address improvements in technology and changing regulatory requirements. All these  changes required by regulatory authorities have been implemented. The changes resulted from operational experience and improvements in technology and had nothing to do with law suits.

GE nuclear energy situation in Japan

GE expresses condolences continue to be with the people of Japan effected by devastating  impact of last 10 days back unprecedented natural disaster. And GE official continue to monitor the events at the Fukushima Daiichi power plant, which suffered a loss of power after tsunami struck site.

During the magnitude 8.9 earth quake the GE Boiling Water Reactor (BWR) performed as designed and initiated safe shut down process. We under stand that back up generator performed as designed to begin the cooling process, shortly thereafter , we understand that tsunami disabled the back up generation system.

Immediately following the earth quake and tsunami, Hitachi -GE  nuclear energy (GE ‘s nuclear joint venture Hitachi)  based in Japan  communicated to Japanese government and Tokyo Electric Power co (TEPCO)the plant operator stating GE is ready to assist them.  The GE -Hitachi alliance assembled incidence response and engineering teams in Tokyo and Wilmington NC to provide 24/7 support.

While Tepco  is managing efforts,GE has been offering assistance from beginning and now taking number of additional actions, providing technical assistance to TEPCO through their joint venture partners in Japan. Providing technical assistance to U.S. Nuclear regularity commission (NRC) which providing assistance to the Japan government.

Engaging GE -net work of more than 1,000 engineers within GE-Hitachi nuclear energy to provide technical assistance to NRC, nuclear energy institute , the government  of Japan and TEPCO.


REACTOR SAFETY

The fleet of GE-Hitachi nuclear energy (GEH) BWR reactors has proven track record of performing reliability and safety for 40 years. GE has been in nuclear industry for more than  half-century. There are currently 92 GE built BWR plants using licensed GE-BWR design operating globally. GE -BWR meet  the rigorous regularity requirements of U.S. Nuclear regularity commission NRC  and other government regulators , and have proven to be safe and reliable.

The unit 1 reactor at Fakushima Daiichi site went into commercial operation in 1971. It is BWR-3 with Mark 1 containment system. That means the reactor is third generation of BWR design. The reactor in unit 1  is same type  as several reactors in U.S. although every reactor designed specially for each project site. All GEH BWR designs meet all NRC requirement for safe operation during and after earth quake for areas where they are licensed and site BWR reactors are designed to able to safety shut down in the event of an earthquake or other natural disaster.

However  GE’s reactor design safe and reliable but   GE-Hitachi nu clear energy to solve core melt down problem in reactor at Fakushima Daiichi plant to avoid people getting effected to radiation.