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Resolution of Generic Safety Issues: Item A-7: MARK I Long-Term Program (Rev. 2) ( NUREG-0933, Main Report with Supplements 1–35 )

DESCRIPTION

During testing for an advanced BWR containment system design (MARK III), suppression pool hydrodynamic loads were identified which had not been considered in the original design of the MARK I containment system. To address this issue, a MARK I Owners’ Group was formed and the assessment was divided into a short-term and a long-term program. The results of the NRC staff's review of the MARK I Containment Short-Term Program were documented in NUREG-0408.701 The long-term program was conducted to provide a generic basis to define suppression pool hydrodynamic loads and the related structural acceptance criteria, such that a comprehensive reassessment of each MARK I containment system could be performed.

A series of experimental and analytical programs were conducted by the MARK I Owners’ Group to provide the necessary bases for the generic load definition and structural assessment techniques. The generic methods proposed by the MARK I Owners’ Group, as modified by the NRC staff's requirements, were to be used to perform plant-unique analyses which would identify the plant modifications, if any, needed to restore the originally intended margin of safety in the MARK I containment designs. This item was originally identified in NUREG-03712 and was later declared a USI in NUREG-0510.186

CONCLUSION

This USI was RESOLVED with the issuance of Supplement 1 to NUREG-0661702 and SRP11 Section 6.2.1.1C. For operating BWRs, MPA D-01 was established by DL/NRR for implementation purposes.

REFERENCES

0002.NUREG-0371, "Task Action Plans for Generic Activities (Category A)," U.S. Nuclear Regulatory Commission, November 1978.
0011. NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants," U.S. Nuclear Regulatory Commission, (1st Ed.) November 1975, (2nd Ed.) March 1980, (3rd Ed.) July 1981.
0186.NUREG-0510, "Identification of Unresolved Safety Issues Relating to Nuclear Power Plants," U.S. Nuclear Regulatory Commission, January 1979.
0701.NUREG-0408, "Mark I Containment Short-Term Program Safety Evaluation Report," U.S. Nuclear Regulatory Commission, December 1977.
0702.NUREG-0661, "Mark I Containment Long Term Program Safety Evaluation Report, Resolution of Generic Technical Activity A-7," U.S. Nuclear Regulatory Commission, July 1980, (Supplement 1) August 1982.