ML19119A008
| ML19119A008 | |
| Person / Time | |
|---|---|
| Site: | 07000157 |
| Issue date: | 04/22/2019 |
| From: | Whaley P University of Texas at Austin |
| To: | Ty Naquin NRC/NMSS/DFCSE/FLB |
| Naquin T | |
| References | |
| Download: ML19119A008 (5) | |
Text
The MCZPR fuel elements were originally shipped to NETL in 6M type drums loaded and transported in a non-critical configuration, and initially stored in the NETL Reactor Room (Rm. 1.104) in the 6M drums. The material was later moved to secured storage racks designed to maintain a multiplication factor (ken} of less than 0.8 under all conditions of moderation in a separate locked room (Auxiliary Equipment Room, is monitored in accordance with 1 O CFR 70.24 by two separate radiation detector systems capable of detecting a criticality that produces an absorbed dose in soft tissue of 20 rads of combined neutron and gamma radiation at an unshielded distance of two meters from the reacting material within one minute. The detector system consists of a Ludlum Model 375 dual gamma and neutron monitor with local and remote alarms. In addition to the criticality accident alarm system
, the ambient radiation level in room 1.104 is measured with multiple Ludlum Model 375 gamma and neutron area radiation monitors with local and remote alarms that report to the reactor control room. The reactor room of the NETL is routinely designated as a Controlled Access Area with strict access controls and a security system. These controls and the facility security system are detailed in the separate NRG-approved Physical Security Plan for Reactor License R-129. The reactor building is supported by a ventilation system that controls differential pressures to direct any potential airborne contamination in the reactor building into the reactor room, monitored by a continuously operating air-particulate detector. An argon purge system provides effluent monitoring backup by sampling the reactor bay atmosphere and discharging through a continuous air monitor. A radioactive material handling facility is installed in a fume hood in the reactor room and may be configured for glove box operations if needed.
Type 6M drums are no longer certified for use, and the alternative package (ES-3100) has a smaller interior cavity than a 6 M drumx It is therefore necessary to reduce the length of the MCZPR fuel elements from 37 to approximately 28 inches by removing some of the aluminum material above and below the fueled region. To facilitate reducing the length of the fuel elements, elements will be removed from the storage rack and handled in accordance with NETL health physics procedures (Radiation Monitoring, ALARA, Radioactive Material Control, etc.). The NETL health physics procedures are reviewed and approved by the Reactor Oversight Committee for conformance with the NRG-approved Radiation Protection Program. As needed, contamination and radiation dose rate surveys will be conducted on the fuel element. In accordance with the approved Physical Security Plan, the auxiliary equipment room and if necessary, the reactor room will be established as Controlled Access Areas while MCZPR fuel is not in the secured storage racks.
The majority of the excess material to be removed to reduce the length of the fuel element is the aluminum outer enclosure tube. The intended area of the cut will be marked, and edge of the active fuel region will be marked to provide visual indication and the margin to the fuel region. The preferred method for cutting the outer support tube will be a standard pipe cutter. In the event that the pipe cutter is not adequate, abrasive cutters may be used (manual or powered blade or cutting wheel). If the pipe cutter is adequate, there will be minimal potential for generation of aluminum particles.