Exelon always does them from below regardless of the calculated 1-3 rem dose savings. This is done to minimize impact to the Refuel Floor schedule. Even if there's >30hr of float in the schedule we still do below as some issue with the refueling equipment will remove that float. We would only unlatch for a rod that had issues from above or perhaps a Turbine Rewind where the Turnbine Deck was critical path by 5 days or more.
We aren't part of the guaranteed profit model with the utility commission anymore, so the schedule must be short and commitments must be met. If we can get the dose, we'll take that too, but we have to work hard for every dollar we earn... The business model is what it is and each site always has a number for how much dose savings would be achieved if unlatching occurred from below, but that initiative doesn't normally make it into the schedule. Contact any of the Exelon sites for good dose data on unlatching control rod drives from below versus the Refuel Floor. Our business model makes us work harder and I'd like to think it's also made us smarter... On the flip side, if I close the Drywell a day early for my tight schedule, I just saved ~8 rem. Glen Vickers Exelon Corp RP Technical Lead, CHP 815-216-2723 (work/cell) From: [email protected] [mailto:[email protected]] On Behalf Of Trimble, Harold Sent: Thursday, August 15, 2013 2:55 PM To: [email protected] Subject: Powernet: RE: BWR - Unlatching control rods from under-vessel At Hope Creek, a low source term plant the impact is approximately 1.1 Rem. From: [email protected] [mailto:[email protected]] On Behalf Of Creamer, Charles E Sent: Thursday, August 15, 2013 3:40 PM To: [email protected] Cc: Schmehl, Richard S Subject: Powernet: BWR - Unlatching control rods from under-vessel The Browns Ferry Nuclear Plant outage planning team is considering unlatching control rods from the drywell under-vessel instead of from the refuel floor during next outage. Does anyone have an analysis of the additional dose cost and /or schedule savings for undervessel control rod unlatching compared to the refuel floor when considering the higher dose rates, and the dose accrued to remove/replace the extra shoot-out steel, etc? Please cc Rick Schmehl on the replies for this post as he is drafting the preplan for this Rick Schmehl 256-729-2007 [email protected] Thank you Chuck Creamer Charles E. Creamer Health Physicist Tennessee Valley Authority Browns Ferry Nuclear Plant P.O. Box 2000 (Mail Stop NAB-1G-BFN) Decatur, Al. 35609-2000 Phone: 256-729-2983 Fax: 256-729-3101 Pager: 1-800-323-4853, pin 30-053 mailto:[email protected] <mailto:[email protected]> This electronic message transmission contains information which may be TVA SENSITIVE, TVA RESTRICTED or TVA CONFIDENTIAL. Any misuse or unauthorized disclosure can result in both civil and criminal penalties. If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the content of this information is prohibited. If you have received this communication in error, please notify me immediately by email and delete the original message. ________________________________ The information contained in this e-mail, including any attachment(s), is intended solely for use by the named addressee(s). If you are not the intended recipient, or a person designated as responsible for delivering such messages to the intended recipient, you are not authorized to disclose, copy, distribute or retain this message, in whole or in part, without written authorization from PSEG. This e-mail may contain proprietary, confidential or privileged information. If you have received this message in error, please notify the sender immediately. This notice is included in all e-mail messages leaving PSEG. Thank you for your cooperation. This e-mail and any attachments are confidential, may contain legal, professional or other privileged information, and are intended solely for the addressee. If you are not the intended recipient, do not use the information in this e-mail in any way, delete this e-mail and notify the sender. -EXCIP
