-- Obsolete -- ISAC Nuclear Zones - Operation During EF-12 to EF-13 Switch

by Aurelia Laxdal, as per Glenn Battersby, Nov. 17, 2005

March 17, 2004

Proposed procedures for ISAC Niclear Exhaust Zones, occupation of spaces during operation of EF13. Written by Glenn Battersby.

1. EF13 is the backup nuclear exhaust fan and will startup automatically under the following circumstances:
   1. Detection of low air flow from EF12.
   2. Loss of compressed air.
   3. Loss of power from external power cut  (EF13 is backed up by diesel power).
   4. Loss of line power due to other reasons, for example, diesel testing.
2. During operation of EF13 there is no longer any backup fan.
3. The procedure for occupied zoned spaces should be informed by the following:
   1. Loose contamination will probably be present in the hot cell.
   2. Loose contamination is unlikely in the target hall, unless the switchover occurs during the transfer of a target.
   3. Typically during RIB production, target contamination is contained within the target vessel. However, air activation will be present outside of the target vessel, but under the sealed shielding.
   4. Switchover of EF12 to EF13 is alarmed in the control room.
   5. During the switchover, for a few 10's of seconds, there will be loss of zoning assurance of the entire area. In event of open hot cell ports, this zoning loss can be almost or totally complete. This will trigger local alarms at the hot cells. Restoration of zoning is provided by EF13 reacing full speed and the local hot cell alarms can be manually reset.
   6. The target hall and hot cell service areas are in direct contact with the hot cells.
   7. Local alarms (hot cell alarm, heard in the hot cell service area) will annunciate in the event of a ventilation failure from EF13.
   8. Note that open ports or lid on a hot cell will reduce or defeat zoning in any event.
   9. New alarms in the target hall and preseparator room will sound if either EF13 is engaged, or loss of depression is detected in the hot cells.
4. Recommended procedure:
   1. Immediate evacuation of the target hall, preseparator, and hot cell service areas.
   2. Access to the area is to be roped off, namely: Door 006, Level B2 (entranceway to the South hot cell service room); and outside (unnumbered) egress door from target hall entrance mezzanine.
   3. Access to these areas requires a respirator until the area has been declared open.
   4. The hot cell service area and the target hall can be declared open for access without a respirator, once swipes and air samples adjecent to the hot cell ports in the target hall and the service areas have been taken and found to be free of contamination.
   5. All operations which have the potential to generate airborne activity must cease while the nuclear ventilation is operating on EF13. (No proton beam operation, no access to the hot cell, no transfer of target modules, and no opening of vacuum systems.)
   6. If the hot cell ports of lid are open, they should be closed as soon as re-access is granted. This step is required to contain the hot cell contents in event of failure of EF13.
   7. Permanent re-occupation requires restoration of the zoning by operation of EF12 and swipes and samples taken once again.