UHI Upper Head Injection, Nitrogen Blowdown

So far this blog has lots in the arena of UHI and there is more to come.

"Where this couldn't be done or wasn't enough, we proposed an upper head injection system."
John W. Simpson, page 199 of Nuclear power from underseas to outer space, Copyright 1995 American Nuclear society.

Of course, Simpson was an old man (80) by the time his book was published. By then the UHI system had been "engineered", installed and abandoned at several units; Catawba and McGuire at Duke, Sequoyah and Watts bar at TVA, and Ohi in Japan.  AEP did not fall for the Westinghouse sales talk that encouraged installing UHI at ice condenser plants (although AEP was conned into the ice condenser units). 

A fast recap:  On October 3, 1984, I submitted my Memorandum, UHI Ultra High Risk, and my employer, the Nuclear Safety Analysis Center (NSAC) of the Electric Power Research Institute then invited me to get lost.  NSAC was not skilled in the game of Nuclear Safety Analysis and the nuclear power utilities that funded NSAC were perfectly content with that.  NSAC was set up after the TMI-2 meltdown to act as a front for nuclear power utilities that needed to assure the public that all was well.

During October 1972 I was employed by Westinghouse Nuclear Energy Systems in a group called Safeguards Development.  Westinghouse was conceiving assorted schemes to address concerns with the adequacy of emergency core cooling systems.  The use of water accumulators with high pressure nitrogen was under study.  I was assigned to review the proposals and I issued the attachment below:

In the above I posed four questions. The essence of the four is in the fourth question that asked if the effects of nitrogen saturation had been considered.  The response from Gallagher of Systems Development stated that "In general, the effects of nitrogen saturation have not been considered."  Also, "The nitrogen dissolved in the spray injection water should be extremely low because of the short time that the accumulator is pressurized, therefore we do not expect the pressure drop through the control valve to lead to substantial nitrogen outgassing."  Gallagher's response is below:

As has been reported in several earlier entries in this blog, the UHI system that Westinghouse installed in several of its ice condenser plants proved to be unwieldy and the systems were abandoned. It turned out that during operation, the nitrogen pressurized accumulators were exposed to pressurized nitrogen for durations up to several months on several occasions.