Harry, Cook experienced elevated dose rates due to having the unit remain at 200 to 350 degrees F from August 1-4, 2007 due to a summer hear wave and high containment atmosphere temperatures. Staying in this coolant temperature range caused the hemotite to change to magnitite 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 warn against not going through a CRUD Burst on PWRs during mid-cycle shutdowns. The 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 report library. 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.
