Field Experience With Ultrasonic Fuel Cleaning

Go to GOOGLE for these references; enter ultrasonic fuel cleaning. By far the most informative is the first reference (above) Ultrasonic Fuel Cleaning at STP. This illustrates the apparatus and the results of field applications. This is a very valuable reference for Students of Nuclear Engineering as well as their faculty.

The two News Releases (above) from EPRI are revealing. The March 19, 2003, release is the first News Release of this activity. This activity proceeded without any safety review by the NRC. The second News Release, October 3, 2005, lists further applications. The third entry from AREVA NP describes their ultrasonic cleaning services with technology licensed from EPRI; this entry is continued below. The final entry (below) leads to an excellent brochure from Westinghouse.

Ultrasonic Fuel Cleaning

The above e-mail was sent to me by Region 4, NRC, in partial response to my inquiry about the application of ultrasonic fuel cleaning at River Bend Station (RBS). See my entry of January 22 for a view of fouled fuel at RBS. Apparently, ultrasonic fuel cleaning has never been applied at RBS, although it has been applied at several other nuclear power plants.

It is interesting that this complex physical chemical process was reduced to practice and applied at several nuclear power plants without any review or authorization by our NRC. There has been no licensing action and there is therefore no documentation of licensing in the NRC's Public Document Room.

I'll have further entries on this matter. In the meantime, eager readers may get interesting background at the NRC website via an ADAMS search at "ML032810635"

Segolene Royal and Nuclear Power in France

No global warming threat in France!

No luck in posting this photo to My Profile

I will try now and then.

Milton Friedman and Price Anderson

Apparently Milton never included Price Anderson among his many investigations. I wonder what he would have thought about all that. Maybe Energy Northwest (the old WPPSS or WHOOPS!) would be operated differently without the Price protection, maybe not.

Fouling in the Late 1950s

The Experimental Boiling Water Reactor (EBWR) operated at the Argonne National Laboratory during the late 1950s. The uranium fuel plates were clad with zirconium as illustrated in the drawing above. The adjacent photograph shows the fouling on a part of a fuel plate that was removed for destructive examination after about two years of service. The fuel plates became fouled with a mixture of aluminum and iron oxides. The source of the aluminum oxide was corrosion of aluminum filler pieces that were included in the structure of the reactor core. The thickness of the fouling ranged from 120 to greater than 200 microns. Of course, this fouling led to substantially higher fuel temperatures and this prevented extended operation of the EBWR at higher power levels. In general the impact of the fouling was only marginally considered and it was never included in evaluating the potential severity of accidents.

I'll have more to report, including on impact of fouling by aluminum oxide on the severity of the SL-1 Accident that I briefly discussed in my entry of December 27, 2006.

Fouling of Reactor Fuel at River Bend

This was presented at the 2004 International ANS Meeting on LWR Fuel Performance, September 20, 2004. Apparently this was never formally reported to the Nuclear Regulatory Commission. At least, I have not found an LER or Inspection Report or other documents that cover this. Please compare this with my entry of January 20, 2007 (12:14 PM, not the later post on that date). More soon on this.

An edit on February 14, 2007: An NRC inspection team finally caught up with this; see ML060600503, February 28, 2006 and my entry on this blog of February 12, 2007, Regulation by Myth,

Double rubble, toil and trouble; Fire burn and ...

This rubble was produced in the test that has gained notariety as RUN 9573. It is briefly described in the entry of January 20, 2007. This was a 7 by 7 assembly of Zircaloy clad electric heaters that simulated nuclear reactor fuel under accident conditions. The assembly was heated to greater than 2200 degrees Farenheit and then quenched with cooling water. At the high temperatures the Zircaloy chemically reacted with the cooling water and that produced even higher temperatures. The severe reactions that led to the rubble also produced the fused clinker in the upper photograph. This clinker was lifted from the center of the assembly during the post test examinations. In the lower photograph note the white heater section where the Zircaloy sheath was completely removed by the intense chemical reactions at the very high temperatures.

DOUBLE RUBBLE: Partial Disclosure

The above summary report, December 14, 1970, is partial disclosure relating to the photograph DOUBLE RUBBLE, TOIL AND TROUBLE.

For clarity the following key sentence and the related footnote is copied here: It appears likely that ignition of the Zircaloy grids led to high rates of heat input* at the elevation one foot above (and below) midplane and this caused overtemperature and failure of the heaters.

*The ratio of surface area to heat capacity for a Zircaloy grid is approximately 15 times that of a heater rod, hence Zircaloy-steam reactions can lead (to) steeper temperature ramps in the vicinity of a Zircaloy grid.

Fouled Fuel at a Nuclear Power Reactor

This is a photo of fouled fuel at a nuclear power plant. There are those who know where and when this was photographed. I have asked them to tell me where and when, but they have not disclosed this. This photo was also presented to the NRC's ACRS, but the transcript of the 2004 meeting does not disclose any details. So, if anyone out there is willing to disclose the facts, please come across on this blog or elsewhere!