DOE-STD-1020-2002, DOE STANDARD: NATURAL PHENOMENA HAZARDS DESIGN AND EVALUATION CRITERIA FOR DEPARTMENT OF ENERGY FACILITIES (JAN-2002)

DOE-STD-1020-2002, DOE STANDARD: NATURAL PHENOMENA HAZARDS DESIGN AND EVALUATION CRITERIA FOR DEPARTMENT OF ENERGY FACILITIES (JAN-2002)., This revision provides information to help meet the requirements of 10 CFR Part 830, “Nuclear Safety Management,” (for Nuclear Facilities), DOE O 420.1 and its associated Guides, accounting for cancellation of DOE O 6430.1A and updating this standard to most current references. This standard has also been brought up-to-date to match the requirements of current model building codes such as IBC 2000 and current industry standards. Since the publication of DOE-STD-1020-94 several new documents have been published which made the seismic design standards of DOE-1020-94 outdated. 􀂃 The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures Parts 1 and 2 introduced new seismic maps for evaluating the seismic hazard. 􀂃 The three model building codes UBC, BOCA, and SBCCI were replaced by the International Building Code (IBC 2000), which adopted the 1997 NEHRP seismic provisions. 􀂃 DOE Order 420.1 and the associated guide, DOE G 420.1-2, were approved and adopted the use of IBC 2000 for PC-1 and PC-2 facilities. Since DOE-STD-1020-94 adopted the UBC for the seismic design and evaluation of PC-1 and PC-2 structures, it was necessary to accommodate the use of the IBC 2000 instead of the UBC for DOE facilities. The seismic hazard in the IBC 2000 is provided by maps that define the seismic hazard in terms of the Maximum Considered Earthquake (MCE) ground motions. Except for locations on or near very active known faults, the maps contain accelerations that are associated with a 2500-year return period earthquake. The ground motions associated with MCE ground motions as modified by the site conditions are used for the design and evaluation of PC-1 and PC-2 structures in this revised DOE standard. The graded approach is maintained by applying a 2/3 factor for PC-1 facilities, and a factor of unity for PC-2 facilities. At the same time PC-3 design ground motions have been adjusted from a 2,000 year return period to a 2,500 year return period. This differs from DOE-STD-1020-94 where different return periods of 500, 1000, 2000 (1000)1 , and 10,000 (5000)11 years were used for PC-1, PC-2, PC-3, and PC-4, respectively. Also, specific performance goals were established for each performance category (PC-1 thru PC-4). These performance goals (in terms of a mean annual probability of failure) were based on a combination of the seismic hazard exceedance levels and accounting for the level of conservatism used in the design/evaluation. In this revised standard the performance goals for PC-1 and PC-2 facilities are not explicitly calculated but are consistent with those of the IBC 2000 for Seismic Use Group I and III, respectively2. For PC-3 SSCs there is no change to the performance goal when compared to the previous version of this standard. This was accomplished by making a slight adjustment to the PC-3 scale factor. Thus, it is not the intent of this revision to alter the methodology for evaluating PC-3 facilities nor to increase the performance goal of PC-3 facilities by increasing return period for the PC-3 DBE from a 2000- year earthquake to a 2500-year earthquake. Rather, the intention is more for convenience to provide a linkage from the NEHRP maps and DOE Standards. All PC-3 SSCs which have been evaluated for compliance with the previous version of this standard do not require any reevaluation considering that the PC-3 level of performance has not changed. Major revisions to DOE-STD-1020-94 were not attempted because of ongoing efforts to develop an ASCE standard for seismic design criteria for Nuclear Facilities. Referring the design of PC- 1 and PC-2 facilities to building codes (such as the IBC 2000) is consistent with design criteria in the proposed ASCE standard.