Harry, Cook experienced elevated dose rates due to having the unit remain at 200 to 350 degrees F from August 1-4, 2006 due to a summer heat wave and high containment atmosphere temperatures. Staying in this coolant temperature range caused the hematite to change to magnetite and move from the fuel to the steam generators bowl and diaphrams. High contamination was seen on removal of eddy current tesing probes and probes had to be replaced more frequently than usual.
Cook ALARA Group had fortunately develop a pc piping system to trap the CRUD coming off the probes and collect the CRUD on River Technology HEPA filter system. CRUD samples were characterized by sending smear samples to Kinectrics in Toronto. An industry OE was issued to perform a CRUD Burst on PWRs during mid-cycle shutdowns to mitigate colloids. The lessons leared for the Cook event was presented at the Las Vegas PWR ALARA Association meeting and contained in their meeting notes. Also, the CRUD analysis can be found on the ISOE Information Sheet from the North American Technical Center at the global ISOE website at www.isoe-network.net go to ISOE Publications / information sheets /north american technical center /first document. Let me know if you need any additional information. Good Luck. . David W. Miller Radiation Protection Dept. Cook Nuclear Plant American Electric Power One Cook Place Bridgman, Michigan 49106 1 269 466-3428 1 269 466 3389 fax 1 217 855 3238 cell ---------------------------------------------------------------- This e-mail message and all attachments transmitted with it from the Nuclear Generation Group of American Electric Power are for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message.
