Nineties



















Advanced Reactor Research in High Gear

While most of the 1980s was spent talking about the next generation of commercial nuclear power plants, the 1990s would be about "putting your money where your mouth is." All around the world work has been underway to design, certify, and/or construct the next generation of nuclear power plants. Reactor suppliers in North America, Japan and Europe have nine new nuclear reactor designs at advanced stages of planning and others at a research and development stage

The next generation reactors will

Reactor vendors both inside the United States and in other countries have heeded the conclusions of the "Utility Requirements Document" (URD). The URD, created by the Electric Power Research Institute, can be considered a "lessons learned"-type document. It specifies a comprehensive set of design specifications desired by utility users. In addition, the document address more than 700 regulatory issues that the U.S. Nuclear Regulatory Commission required to be resolved in any future designs. The first three volumes of the URD were completed in 1990 and contain more than 20,000 detailed requirements for ALWR designs. The NRC review documents conclude that designs that meet the URD requirements are licensable designs. While the NRC was reviewing the design and regulatory features describe in the URD, they were also evaluating and implementing the URD recommendations for With the URD complete a coalition of domestic and international utilities (organized through EPRI), vendors, and the Department of Energy began working to develop and license ALWR designs that meet the URD requirements. The Advanced Reactor Corporation (ARC) was established at that time to serve as a vehicle to merge, under utility management, government and utility funds to support the "First of a Kind Engineering" (FOAKE) on selected designs. Funding of the FOAKE effort was provided through matching contributions from DOE and private industry.

The table below summarizes the ALWR designs that have been actively being pursued this decade.

Country and developer Reactor Size MWe Design Process Main Features
1300 Commercial operation in Japan since 1996-7. In US: NRC final design certification May 1997, FOAKE
  • Evolutionary design
  • More efficient, less waste
  • Simplified construction (48 months) and operation
  • 1300 NRC final design certification May 1997. Some elements in new S. Korean reactors.
  • Evolutionary design
  • Increased reliability
  • Simplified construction and operation
  • 600 NRC final design approval Sept. 1998, FOAKE
  • Passive safety features
  • Simplified construction and operation
  • 3 years to build
  • 60-year plant life
  • 600 NRC Submittal Withdrawn in 1996
  • Passive safety features
  • Simplified construction and operation
  • Japan (utilities, Westinghouse, Mitsubishi) APWR 1500 Basic design in progress, twin unit planned at Tsuruga
  • Hybrid safety features
  • Simplified Construction and operation
  • France-Germany (Framatome ANP) EPR (PWR) 1550-1750 Confirmed as future French standard, design completed 1997
  • Evolutionary design
  • Improved safety features
  • High fuel efficiency
  • Low cost electricity
  • Germany (Framatome ANP) SWR (BWR) 1000 Under development
  • Innovative design
  • High fuel efficiency
  • Passive safety features
  • Sweden (Westinghouse) BWR 90+ 1500 Under development
  • Evolutionary design
  • Short construction time
  • Enhanced safety features
  • Russia (Atomenergoproject & Gidropress) V-407
    V-392
    (PWR)
    640
    1000
    respectively
    Construction of first V-407 unit pending, V-392 units planned
  • Passive safety features
  • 60-year plant life
  • Simplified construction and operation
  • Russia (AEE) VVER-91 (PWR) 1000 Two being built at Tianwan in China
  • Evolutionary design
  • Enhanced safety features
  • Canada (AECL) CANDU-9 925-1300 Licensing approval 1997
  • Evolutionary design
  • Single stand-alone unit
  • Flexible fuel requirements
  • Passive safety features
  • Canada (AECL) ACR 700
    1000
    Development to 2005.
  • Evolutionary design
  • Light water cooling
  • Low-enriched fuel
  • Passive safety features
  • South Africa (Eskom, BNFL) PBMR 110 (module) prototype due to start building in 2002
  • Modular plant, low cost
  • Direct cycle gas turbine
  • High fuel efficiency
  • Passive safety features
  • USA-Russia et al (General Atomics - Minatom) GT-MHR 285 (module) Under development in Russia by multinational joint venture
  • Modular plant, low cost
  • Direct cycle gas turbine
  • High fuel efficiency
  • Passive safety features


  • In the United States the first designs targeted for design certification were General Electric's Advanced Boiling Water Reactor (ABWR) and Simplified Boiling Water Reactor (SBWR), ABB Combustion Engineering's System 80+, and Westinghouse's Advanced Passive 600 MW Reactor (AP600)

    General Electric's Advanced Boiling Water Reactor (ABWR) and ABB Combustion Engineering's System 80+ (a pressurized water reactor) fall into the category of evolutionary designs. These two designs were the first to receive final design approval under the NRC's reformed certification process. Final design approval for both designs came from the NRC in the summer of 1994. A public review process completed the certification of these designs by the end of 1995, complying with the most recent provisions of the Code of Federal Regulations (10CFR52).

    The midsize, passive safety reactors by Westinghouse (AP600) and General Electric (SBWR) began following on the path to design certification about the same time as the evolutionary design. However, since the passive safety system represented a totally new concept in safety reliance, a more extensive testing program had to be undertaken with these reactors. The AP600 received it final design approval in September 1998. General Electric withdrew its SBWR submittal in 1996.

    Passive Reactor Testing Program

    While the evolutionary designs of the ABWR and the System 80+ represented a significant improvement over conventional reactor designs, no new safety related phenomena was expected. In contrast the passive safety systems of the SBWR and AP600 represented a totally new approach to safety. Since GE chose to withdraw it's SBWR submittal, little information is available highlighting their testing program (planned testing was completed, but it never received NRC/ACRS review). Westinghouse did complete quite an extensive test and analysis program. Utilizing both separate-effects and integral-system facilities, Westinghouse investigated the behavior of the AP600 passive safety systems and developed a database for validation of the computer codes used to perform accident and transient analyses. Key aspects of the test and analysis program included:
  • Core Makeup Tank (CMT) Test Program to characterize the CMT over an extended range of thermal-hydraulic conditions.

  • Automatic Depressurization System (ADS) Test Program, both to characterize the steam flow through the IRWST sparger and to test the thermal-hydraulic behavior of the ADS piping network.

  • Passive Residual Heat Removal (PRHR) System Test Program to generate data for design and characterization of the AP600 PRHR heat exchanger.

  • Oregon State University Advanced Plant Experiment (APEX) Test Program to obtain integral-systems data for code validation; emphasis was placed on low-pressure and long-term core cooling behavior for design-basis, small-break loss-of-coolant accidents (LOCAs).

  • SPES-2 High-Pressure, Full-Height Integral-Systems Test Program to obtain integral-systems data for code validation; the particular focus was on accident progression from initiation to establishment of stable IRWST injection.

  • Passive Containment Cooling System Test Program to obtain integral-systems test data on the thermal-hydraulic performance of this system to support code validation.
  • This extensive test and analysis program was necessary to validate the accident analysis codes applied to new, passive emergency core cooling systems for which there is not a significant experience base.

    For the NRC to confirm the integrity of these designs, they would have to participate in an aggressive testing program.

    For reasons both noble (education) and practical (budget), the NRC chose to depart from its traditional use of the nation's national laboratories and sponsored research at universities. Oregon State and Purdue University were chosen to host scaled integral test facilities of the AP600 and the SBWR. Led by Jose Reyes (OSU) and Mamouri Ishii (PU), both leaders on the subject of plant scaling, these facilities were designed to best represent the relevant new phenomena on the smaller scale facility. In additional to these integral tests, the NRC programs included integral-systems testing performed at the Japan Atomic Energy Research Institute ROSA-AP600 facility and improved phenomenological modeling for their advanced accident analysis computer codes RELAP5 and CONTAIN.

    Implementing ALWR Results in Today's Plants

    Despite all this effort on creating the next generation of light water reactors, the ALWR program has developed technologies that could directly benefit currently operating nuclear plants. In January 1994, EPRI prepared a report identifying such technologies, which include improved analytical methods, retrofittable hardware, engineering guidelines, and licensing improvements. Some of these represent significant improvements on current practice; others are breakthrough innovations.

    Many items from this report have been reviewed with member utilities for possible implementation at existing plants. Specific technologies usable now or in the near future include more-realistic estimates of probable radiation release (source term) for use in planning accident response, passive catalytic recombiners to reduce combustible gases after an accident, automated fuel transfer equipment that can reduce the time needed to refuel boiling water reactors, and in-core instrumentation to provide greater operating flexibility in pressurized water reactors.

    International Nuclear Safety Program

    While the big story in nuclear safety research during the 1990s, its has not been the only effort. The U.S. Department of Energy participates in a cooperative effort to improve safety at Soviet-designed nuclear power plants. In eight partnering countries -- Russia, Ukraine, Armenia, Bulgaria, the Czech Republic, Hungary, Lithuania, and Slovakia -- joint projects are correcting major safety deficiencies and establishing nuclear safety infrastructures that will be self-sustaining.

    The joint efforts originated from U.S. commitments made at the G-7 conference in 1992, when world leaders, through heightened international concern, agreed to collaborate with host countries to reduce risks at older Soviet-designed reactors. Since that time, U.S. efforts have expanded to include safety-related activities at 20 nuclear power plants with 64 operating reactors. The work is conducted in cooperation with similar efforts initiated by Western European countries, Canada, and Japan, as well as the Nuclear Energy Agency, International Atomic Energy Agency, and the European Bank for Reconstruction and Development.

    The United States supports host countries in their efforts to conduct safety evaluations in keeping with international practices install safety equipment establish a culture in which safety takes priority over power production develop improved safety procedures and train workers to use them establish training centers for reactor personnel develop legislative and regulatory frameworks for plant design, construction, and operation that meet international requirements address the extraordinary problems at Chornobyl.

    The primary objectives are:

  • reduce the likelihood of a nuclear accident that could destabilize the new democratic governments of Russia, Ukraine, and Eurasia. Such an accident might require a massive influx of international aid and could threaten the viability of nuclear power worldwide.

  • promote a stable business climate for international investments in the former Soviet Union and Eurasia.

  • provide protection for Europe's public, economic, and environmental health and U.S. personnel located in Europe.

  • Bibliography

    1) J. Douglas, "Reopening the Nuclear Option," EPRI Journal, Dec. 1994.

    2) Letter, R. R. Seale (ACRS) to S. A. Jackson (NRC), REPORT ON THE SAFETY ASPECTS OF THE WESTINGHOUSE ELECTRIC COMPANY APPLICATION FOR CERTIFICATION OF THE AP600 PASSIVE PLANT DESIGN, July 23, 1998.

    3) "INSC Home Page," International Nuclear Safety Center, http://www.insc.anl.gov.

    4) "Advanced Reactors," Nuclear Issues Briefing Paper 16, Uranium Information Centre Ltd., September 1998. See also http://www.uic.com.au/nip16.htm