Design and Performance of ABWR-II Safety System
- Toshiba Corporation, 8, Shinsugita-cho, Isogo-ku, Yokohama, 235-8523 (Japan)
- Hitachi, Ltd., 1-1, Saiwai-cho 3-chome, Hitachi, 317-8511 (Japan)
- Tokyo Electric Power Company, 1-3, Uchisaiwai-cho 1-chome, Chiyoda-ku, Tokyo, 100-0011 (Japan)
In order to meet utility demands after successful completion of ABWR development, ABWR-II design provides more emphasis on beyond-DBA capability to achieve further enhancement of safety such as the practical exclusion of the probability of emergency evacuation/resettlement. Optimization of safety and economic aspects is also to be strongly pursued. The active core and containment cooling system for the accomplishment of these objectives, is realized as the rationalized four division RHR system. The front line consists of complete four trains, and the supporting cooling circuit consists of two loops, however, key active components basically have N+2 capability. Hence the configuration enables on-line maintenance, and simultaneously improves safety and plant availability. The passive heat removal system is adopted as an in-depth backup for reactor and containment cooling. These systems practically eliminate necessity of containment venting as a means of overpressure protection. Several types of containment configuration have been studied in addition to conventional containment design which meets design criteria. In the separated drywell concept, drywell is separated at RPV skirt into upper and lower drywell. This configuration provides larger volume for non-condensable gases compared to conventional containment of the same total volume, and reduces pressure during an accident. In the other concept also aiming at no evacuation, wet well is extended up to the operation floor along with containment wall. Rupture disks installed between this extended area and wet well, open when the containment pressure exceeding the design pressure in case of severe accident. These containment designs also consider other severe accident phenomena on a safety margin basis, according industrial guideline. As a result of these design evolution, ABWR-II achieved distinguished safety feature. Both of probabilistic and deterministic consideration for beyond DBA event has been made from design stage. Adopting evolutional system design, key performance and defense-in-depth capability expected for the next generation reactor are provided. System integration and economical benefit are realized simultaneously so that utility requirements are fulfilled. (authors)
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 21160667
- Resource Relation:
- Conference: ICAPP'04: 2004 international congress on advances in nuclear power plants, Pittsburgh, PA (United States), 13-17 Jun 2004; Other Information: Country of input: France; 6 refs; Related Information: In: Proceedings of the 2004 international congress on advances in nuclear power plants - ICAPP'04, 2338 pages.
- Country of Publication:
- United States
- Language:
- English
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