UHI Ultra High Risk, October 3, 1984, Led to an Abnormal Occurrence Report to Congress

This is my seventh consecutive entry in matters stemming from my EPRI-NSAC Memorandum, UHI Ultra High Risk, October 3, 1984.

Yes, my NSAC Memorandum, UHI Ultra High Risk, led to an Abnormal Occurrence Report to Congress.  Here it is, click on it to enlarge and back arrow to get back here.

So, on January 28, 1985, Denton as Director of the Office of Nuclear Regulation, reports, "This condition is beyond the design bases for the plant and is not specifically analyzed in the safety analysis report."  Denton continues: "The effect of nitrogen in the reactor during a LOCA has not yet been analyzed, however, NRR is placing a work order with Sandia National laboratory (SNL) to assess the effect of isolation valve failure during a large LOCA in a UHI plant."

A year later, Sandia submitted its analysis to NRC, but noted that the report had information proprietary to Westinghouse, and NRC did not make the report available to the public. 

I  left the matter alone for about 10 years, but then I went after the NRC for the report.  Nothing was producing results, so I faxed the following to the Chairman, NRC on May 30, 1994.

And on June 17, 1994 I was sent the following reply.  It reveals that NRC had not even had a copy of the Sandia report and that "extraordinary measures" were required to "locate and acquire" a copy of the letter report.  What in the world did  NRC do with this Sandia report that was highlighted in the Abnormal Occurrence Report to Congress?  We will never know.  Moreover, I was not promptly sent the report once NRC found it. 

After a while, I was sent a somewhat illegible copy of the report. Following is from page 13 or is it 15? It is not obvious from the poor copy. This Sandia letter report suggests that failure of the UHI isolation valves to close may be beneficial because of the addtitonal water that is injected into the upper head. 

About six years ago I was not successful in getting NRC to perform evaluations of the UHI situation that prevailed during 1984.  Following is an e-mail exchange that I had with Dean Dobranich of Sandia who had performed the analyses of UHI for the NRC during 1985.   Work at Sandia proceeded during 1985 and was reported to NRC in periodic contacts during 1985 and in a letter report during January 1986.

NRC did not adequately fund Sandia for the UHI analyses and the scope of work was far too narrow.  For example, with four out of four liquid level detectors reverse connected there was no way of determining the amount of water that would be injected.  In the extreme, but not improbable case, there would be no water injected.  More likely, there would be some water available, however, the amount would likely be substantially less than 1800 cubic feet.  Instead of 1800 cubic feet of water, there might be 400 cubic feet of water and 1400 cubic feet of high pressure nitrogen.

Moreover, the water would be saturated with dissolved nitrogen which would be released during the injection.