Abstract The international reactor innovative and secure (IRIS) is a modular pressurized water reactor with an integral configuration (all primary system components – reactor core, internals, pumps, steam generators, pressurizer, and control rod drive mechanisms – are inside the reactor vessel). The IRIS plant conceptual design was completed in 2001 and the preliminary design is currently underway. The pre-application licensing process with the United States Nuclear Regulatory Commission (USNRC) started in October 2002. The first line of defense in IRIS is to eliminate event initiators that could potentially lead to core damage. If it is not possible to eliminate certain accidents altogether, then the design inherently reduces their consequences and/or decreases their probability of occurring. One of the most obvious advantages of the IRIS Safety-by-Design™ approach is the elimination of large break loss-of-coolant accidents (LBLOCAs), since no large primary penetrations of the reactor vessel or large loop piping exist. While the IRIS Safety-by-Design™ approach is a logical step in the effort to produce advanced reactors, the desired advances in safety must still be demonstrated in the licensing arena. With the elimination of LBLOCA, an important next consideration is to show the IRIS design fulfills the promise of increased safety also for small break LOCAs (SBLOCAs). Accordingly, the SBLOCA phenomena identification and ranking table (PIRT) project was established. The primary objective of the IRIS SBLOCA PIRT project was to identify the relative importance of phenomena in the IRIS response to SBLOCAs. This relative importance, coupled with the current relative state of knowledge for the phenomena, provides a framework for the planning of the continued experimental and analytical efforts. To satisfy the SBLOCA PIRT project objectives, Westinghouse organized an expert panel whose members were carefully selected to insure that the PIRT results reflect internationally recognized experience in reactor safety analysis, and were not biased by program preconceptions internal to the IRIS program. The SBLOCA PIRT Panel concluded that continued experimental data and analytical tool development in the following areas, in decreasing level of significance, are perceived as important with respect to satisfying the safety analysis and licensing objectives of the IRIS program: (1) steam generator; (2) pressure suppression system, containment dry well and their interactions; (3) emergency heat removal system; (4) core, long-term gravity makeup system, automatic depressurization system, and pressurizer; (5) direct vessel injection system and reactor vessel cavity.
[1]
C. D. Fletcher,et al.
Use of phenomena identification and ranking (PIRT) process in research related to design certification of the AP600 advanced passive light water reactor (LWR)
,
1996
.
[2]
U. S. Rohatgi,et al.
Preliminary phenomena identification and ranking tables for simplified boiling water reactor Loss-of-Coolant Accident scenarios
,
1998
.
[3]
G. E. Wilson,et al.
The role of the PIRT process in experiments, code development and code applications associated with Reactor Safety analysis
,
1998
.
[4]
U. S. Rohatgi,et al.
Preliminary Phenomena Identification and Ranking Tables (PIRT) for SBWR start-up stability
,
1997
.
[5]
Lawrence E. Hochreiter,et al.
Identification and Ranking of Phenomena Leading to Peak Cladding Temperatures in Boiling Water Reactors During Large Break Loss of Coolant Accident Transients
,
2002
.
[6]
Hisashi Ninokata,et al.
The design and safety features of the IRIS reactor
,
2004
.
[7]
D. P. Griggs,et al.
Development of a phenomena identification and ranking table (PIRT) for a postulated double-ended guillotine break in a production reactor
,
1989
.
[8]
C. D. Fletcher,et al.
Phenomena identification and ranking tables for Westinghouse AP600 small break loss-of-coolant accident, main steam line break, and steam generator tube rupture scenarios
,
1997
.
[9]
Beatrice Gralton,et al.
Washington DC - USA
,
2008
.