Thursday, March 29, 2007

Here I am.

e-mail to Chairman, NRC, Published on NRC web, ADAMS ML070860793

Date: 03/21/2007 1:03 PM

Subject: What I Should Have Said in Less Than Two Minutes

On February 20-21, 2007, the DOE's Nuclear Energy Research Advisory Committee held an open meeting in Idaho Falls, Idaho. They discussed several activities related to nuclear power developments worldwide. Time was allotted for public comments and I discussed Regulation by Myth for about eight minutes. However, following is what I should have said in less than two minutes.

Gentlemen, you are likely eager to bail out of here after the foregoing endless sets of slide presentations. Today I have only virtual slides. Slide one lists eight nuclear power plants that have applied ultrasonic fuel cleaning. Slide two shows the ultrasonic fuel cleaning equipment. Slide three has two photographs of fouling on nuclear power plant fuel rods. Slide four shows that with fouling, light water reactors have operated with fuel cladding surface temperatures in the range of 1200 degrees Fahrenheit and above (instead of the range of 550 to 600 degrees Fahrenheit that is the design basis for long term operation). Slide five is fantastic and nonexistent; it shows Zircaloy-water reactions: the growth of Zirconium dioxide scale, the increase in dissolved oxygen concentration and the hydriding and increase of dissolved hydrogen concentration in Zircaloy cladding, with time at six reaction temperatures: 600, 800, 1100, 1500, 2000 and 2500 degrees Fahrenheit. To produce slide five, more experiments are needed with Zircaloy cladding, as called for by the AEC Commissioners decades ago, December 28, 1973.

Tuesday, March 27, 2007

FLECHT Run 9573, Leyse Report, Dec. 14, 1970

DOUBLE RUBBLE: FLECHT Run 9573, December 11, 1970

FLEC—500 — Facility Operation

The final FLECHT test (Bundle Z-lO) was completed on December 11, 1970. The test was run with flooding of 1 in/sec. beginning at 2000 degrees F. Several heaters failed approximately 18 seconds after flooding when the peak indi­cated midplane temperature was 2325 degrees F. Heater failure at this temperature is unlikely, particularly under conditions of decay heat and increasing temperature. The steam probe thermocouple located one foot above midplane in close proximity to a Zircaloy grid indicated an extremely rapid rate of temperature rise (over 3OO F/sec.)_beginning approximately 12 seconds after flooding and reached 2450 degrees F by 16 seconds after flooding. 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. Test results are currently being studied.

The temperature measuring system in FLECHT was the object of a complete audit by Idaho Nuclear Corporation prior to the final FLECHT test. The audit was very thorough and required approximately seven days. IdahoNuclear Corporation found that the total temperature measurement system was highly reliable and the final Zircaloy test was run with no changes to the system.

*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.


Test Engineering
R. H. Leyse

The original copy of this report is below.