RPV steam generator pressure boundary
As the types of SG tube degradation affecting PWR SGs has changed, and improvements in tube inspection and repair technology have occurred, current SG regulatory requirements and guidance have become increasingly out of date. This regulatory situation has been dealt with on a plant-specific basis, however to resolve this problem in the long term, the NRC has begun development of a performance-based rule. As currently structured, the proposed steam generator rule would require licensees to implement SG programs that monitor the condition of the steam generator tubes against accepted performance criteria to provide reasonable assurance that the steam generator tubes remain capable of performing their intended safety functions. Currently the staff is developing three performance criteria that will ensure the tubes can continue to perform their safety function and therefore satisfy the SG rule requirements. The staff, in developing the criteria, is striving to ensure that the performance criteria have the two key attributes of being (1) measurable (enabling the tube condition to be {open_quotes}measured{close_quotes} against the criteria) and (2) tolerable (ensuring that failures to meet the criteria do not result in unacceptable consequences). A general description of the criteria are: (1) Structural integrity criteria: Ensures that the structural integrity of the SG tubes is maintained for the operating cycle consistent with the margins intended by the ASME Code. (2) Leakage integrity criteria: Ensures that postulated accident leakages and the associated dose releases are limited relative to 10 CFR Part 50 guidelines and 10 CFR Part 50 Appendix A GDC 19. (3) Operational leakage criteria: Ensures that the operating unit will be shut down as a defense-in depth measure when operational SG tube leakage exceeds established leakage limits.
- Research Organization:
- US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Office of Nuclear Regulatory Research; Brookhaven National Lab. (BNL), Upton, NY (United States)
- OSTI ID:
- 269670
- Report Number(s):
- NUREG/CP-0149-Vol.3; CONF-9510156-Vol.3; ON: TI96007986; TRN: 96:016776
- Resource Relation:
- Conference: 23. water reactor safety information meeting, Bethesda, MD (United States), 23-25 Oct 1995; Other Information: PBD: Mar 1996; Related Information: Is Part Of Twenty-third water reactor safety information meeting. Volume 3, structural and seismic engineering, primary systems integrity, equipment operability and aging, ECCS strainer blockage research and regulatory issues; Monteleone, S. [comp.] [Brookhaven National Lab., Upton, NY (United States)]; PB: 236 p.
- Country of Publication:
- United States
- Language:
- English
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