North Anna's reply: We have had to install shielding on the floor/gap above the fuel transfer tube due to streaming. Inside containment we use a vendor purchased water shield in conjunction with lead blankets. In our Fuel Building we have installed lead blankets on the floor/gap of the fuel transfer tube into containment.
We use specialty made lead blankets for our NUHOMS dry cask storage while vacuuming drying and welding activities. This has reduced radiation streaming from the annulus (area between the transport cask and dry shielded canister) and reduced overall worker exposure. More recently, we added more horizontal storage modules (HSMs) to our ISFSI. We constructed a scaffold barrier with lead blankets to prevent entry into a locked HRA and reduce dose rates at the opening. For work on the dry storage casks at the ISFSI, we purchased large poly sheets (approximately 5x8) to reduce neutron exposure during long maintenance campaigns. Barbara J. Thompson Supervisor of Exposure Control Dominion - North Anna Power Station Email: [email protected] Phone: 540-894-2605 Beeper: #3469 FAX: 540-894-2408 From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Thursday, September 09, 2010 4:17 PM To: [email protected] Cc: [email protected] Subject: Powernet: Temporary Shielding Usage in Pits Palo Verde requests information on the following topic: There are occasions when work is performed in with areas where shine or streaming radiation contributes to a substantial portion of the total dose. For example, at Palo Verde during dry cask storage campaigns workers in the Cask Load and Washdown Pits get a significant amount of dose from the adjacent Spent Fuel Pool. During mostly due to shine / streaming through the Weir gates that separate the areas. Question for this utilities with similar configurations, have you considered or do you shield these areas? Please provide contact information or contact Darin Hall, RP Dry Cask Storage Team Leader, at (623) 393-1434 or [email protected]<mailto:[email protected]> CONFIDENTIALITY NOTICE: This electronic message contains information which may be legally confidential and or privileged and does not in any case represent a firm ENERGY COMMODITY bid or offer relating thereto which binds the sender without an additional express written confirmation to that effect. The information is intended solely for the individual or entity named above and access by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution, or use of the contents of this information is prohibited and may be unlawful. If you have received this electronic transmission in error, please reply immediately to the sender that you have received the message in error, and delete it. Thank you.
