Nuclear Regulatory Commission November 25, 2008 – Federal Register Recent Federal Regulation Documents

The Nuclear Regulatory Commission (NRC) will consider the issues raised in a petition for rulemaking (PRM) submitted by Mark Edward Leyse in the NRC's rulemaking process. The petition was dated March 15, 2007, and was docketed as PRM-50-84. The petitioner requests that the NRC amend its regulations to require that nuclear power reactors be operated in a manner to limit the thickness of crud layers and/or the thickness of oxide layers on fuel rod cladding surfaces to ensure that the facilities operate in compliance with the emergency core cooling system (ECCS) acceptance criteria. The petitioner also requests that the requirements pertaining to ECCS evaluation models be amended to explicitly require that the steady-state temperature distribution and stored energy in reactor fuel at the onset of a postulated loss-of-coolant accident (LOCA) be calculated by factoring in the role that the thermal resistance of crud and/or oxide layers on fuel cladding plays in increasing the stored energy of the fuel. Lastly, the petitioner requests that the acceptance criteria for analyses of ECCS cooling performance for light-water nuclear power reactors be amended to stipulate a maximum allowable percentage of hydrogen content in the cladding of fuel rods. The NRC will consider the petitioner's first two requests in PRM-50-84 because the underlying technical considerations regarding the effects of crud and oxide growth on ECCS analyses noted by the petitioner are sufficiently related to an ongoing NRC rulemaking activity on ECCS analysis acceptance criteria. The NRC will consider the petitioner's third request because the NRC has already initiated rulemaking activities that will address the petitioner's underlying technical concerns on fuel cladding embrittlement. While the NRC will consider the issues raised in the petition in its rulemaking process, the petitioner's concerns may not be addressed exactly as the petitioner has requested. During the rulemaking process, the NRC will solicit comments from the public and will consider all comments before issuing a final rule.