MH-1A CONTROL ROD EJECTION ACCIDENT ANALYSIS: TWELVE ROD BANK OPERATION.
Abstract
The MH-1A control rod ejection accident can result in core damage when postulated to occur during ten rod bank operation, a rod programming scheme presently utilized at the beginning of core life to lessen the magnitude of the axial power peak. Analyses have been performed to determine if, and under what conditions, core damage from this accident can be prevented by operating the MH-1A in a twelve rod bank configuration at the beginning (and throughout) core life. A parametric study indicates that, during twelve rod bank operation, core damage does not result if the rod ejection accident is initiated at a primary system temperature of 190F and above. This does not represent any restriction on normal plant operations; under present procedures, the primary system temperature is brought to 230F before any control rods are withdrawn. As the result of a core steady-state thermal analysis, it is recommended that operation be limited to 90% full power at beginning of life, when the twelve rod bank is between 14.9 inches and 18.2 inches inserted, due to the increase in the axial power peak. This is to maintain the core steady-state safety margins at their present level. However, a review of the accident analyses indicates that none of the accidents are significantly affected by the increase in the axial power peak; core safety is maintained by the present scram and rod insertion set points. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 15, 1968
- Accession Number
- AD0676686
Entities
People
- David R. Pankratz
- Heriberto Plaza
- James T. Rhodes