Eric, When you cool back down to Mode 5 you will most likely experience a temperature related crud burst and as you indicated you plan on removing the Pressurizer manway afterward. That will produce an oxygenation crud burst similar to a hydrogen peroxide add, and considering where your current RCS Co-58 activity is it's hard to see any benefit in doing a peroxide injection.
Following an extended shutdown period, just introducing Rx Coolant pump flow and the temperature changes should be sufficient impetus for crud release. Palo Verde experience with Co-60 has shown that this is a tightly adhered corrosion layer below the ex-core deposits that the hydrogen peroxide is designed to liberate. I think that your focus should be geared more toward crud burst clean-up as far as source term reduction efforts go. Seth From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, October 16, 2012 1:41 PM To: [email protected] Subject: Powernet: Question: To crud burst or not after an extended shutdown San Onofre Unit 2 is preparing to heat up from cold shutdown and reach Normal Operating Temperature and Pressure but stay non-critical to perform system and new component testing. Upon cooling back down to Mode 5, we can either add hydrogen peroxide for a crud burst or not (the Pressurizer manway cover will be removed afterward). Since the unit has been shutdown for ~10 months, the question was raised - what is the benefit of a crud burst when the RCS Co-58 activity is currently about two orders of magnitude below typical shutdown values. Does anyone out there have any experience, either pro or con, with a decision on crud bursts after an extended shutdown? We perceive some long-term benefit for Co-60 reduction but assume that is not very quantifiable. Minimal work will be performed in containment during the current outage following NOP/NOT testing. The major benefit in source term reduction would be in decreased dose rates during the next outage period. Please reply to me by Thursday, October 18 if possible. Thanks, Eric Eric M. Goldin, CHP Southern California Edison <[email protected]> ----------------------------------- Powernet - a service of the Health Physics Society Power Reactor Section Powernet archives at http://www.mail-archive.com/[email protected]/ Reply to: [email protected] If Questions, contact Mike Russell, CHP at [email protected] --- NOTICE --- This message is for the designated recipient only and may contain confidential, privileged or proprietary information. If you have received it in error, please notify the sender immediately and delete the original and any copy or printout. Unintended recipients are prohibited from making any other use of this e-mail. Although we have taken reasonable precautions to ensure no viruses are present in this e-mail, we accept no liability for any loss or damage arising from the use of this e-mail or attachments, or for any delay or errors or omissions in the contents which result from e-mail transmission.
