Development of Emergency Response Guidelines (ERGs) for AP1000
- Kansai Electric Power Co., Inc., P.O. Box 355, Pittsburgh, PA, 15230-0355 (United States)
- ANSALDO NUCLEARE S.p.A, P.O. Box 355, Pittsburgh, PA, 15230-0355 (United States)
- Westinghouse Electric Company, LLC, P.O. Box 355, Pittsburgh, PA, 15230-0355 (United States)
The AP1000 is two-loop 1100 MWe advanced pressurized water reactor (PWR) that uses passive safety features to enhance plant safety and to provide significant and measurable improvements in plant simplification, reliability, investment protection and plant costs. The AP1000 uses proven technology, which builds on over 30 years of operating PWR experience. The AP1000 final design certification has been approved by the NRC in December, 2005. The Emergency Response Guidelines (ERGs) have been developed for the AP1000. The generic ERGs for the low pressure reference PWR plant were used as the basic documents to develop the AP1000 ERGs. The AP1000 design differences from the reference plant were reviewed and reflected in the process of developing operational steps in each ERG. The AP1000 used PRA in both design and licensing. The provisions of the AP1000 PRA were also reviewed and incorporated into the ERGs Although the AP1000 design does not require operator actions for the first 72 hours after accidents, the operator actions with both safety-related and non-safety-related equipment have an important role to mitigate the consequence of accidents. In the event of a LOCA, the AP1000 safety-related passive core cooling system (PXS) provides sources of core makeup water along with an automatic depressurization system (ADS) consisting of several sets of redundant flow paths which are sequentially opened in stages to reduce the reactor coolant system (RCS) pressure in a controlled manner. The final stage of this system, ADS-4, consists of four large valves that open off the hot legs, reducing the pressure to allow gravity injection from the in-containment refueling water storage tank (IRWST) and eventually the containment sump recirculation. The AP1000 has non-safety-related normal residual heat removal system (RNS) pumps which can be used to provide low pressure pumped injection of cask loading pit and/or IRWST water and recirculation of containment water. These pumps are not required to operate following accidents. However, it is expected that they should be used if available and their operator actions should be incorporated into ERGs to restore safety-related PXS and/or to avoid ADS-4 actuation. Several LOCA and other cases were analyzed, including consideration of such operator actions as RNS injection, to support the development process of the AP1000 ERGs. These cases were modeled using the best-estimate state-of-art RELAP5 code. The analyses results show that RNS injection is effective for a typical small LOCA to avoid ADS-4 actuation. (authors)
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 21016430
- Resource Relation:
- Conference: 2006 International congress on advances in nuclear power plants - ICAPP'06, Reno - Nevada (United States), 4-8 Jun 2006; Other Information: Country of input: France; 9 refs; Related Information: In: Proceedings of the 2006 international congress on advances in nuclear power plants - ICAPP'06, 2734 pages.
- Country of Publication:
- United States
- Language:
- English
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