POLICY ISSUE 

(Notation Vote) 

January 8, 2009 SECY-09-0006

FOR: The Commissioners 

FROM: R. W. Borchardt 

 Executive Director for Operations 

SUBJECT: CRITICAL RESEARCH FACILITIES FOR SEVERE ACCIDENT 

RESEARCH AT LIGHT WATER AND ADVANCED REACTORS 

PURPOSE: 

The purpose of this paper is to provide recommendations to the Commission about critical 

research facilities, both domestic and international, that will be needed for future research on 

severe accidents at light water and advanced reactors and the appropriate level of U.S. Nuclear 

Regulatory Commission (NRC) involvement in those facilities as specified in Staff Requirements 

Memorandum (M080317B). This paper does not address any new commitments or resource 

implications. 

SUMMARY: 

NRC has a large number of bilateral and multilateral agreements for the exchange of nuclear 

safety information within the international community. NRC also participates in the Organisation 

for Economic Cooperation and Development’s (OECD’s) Nuclear Energy Agency (NEA) and 

several of its subgroups in planning for the worldwide availability of experimental facilities. The 

NRC has cooperated with the domestic organizations in gathering experimental data important 

to nuclear safety. The staff’s review of severe accident research facilities to identify those that 

are critical to maintain revealed that very few are necessary to maintain for the long term. The 

NRC may need to continue participation with a few of those research facilities beyond the 

present program. The staff recommends that the Office of Nuclear Regulatory Research (RES) 

continue to negotiate bilateral and multilateral agreements for light water reactor experimental 

programs as discussed below. 

CONTACT: Jocelyn Mitchell, RES/DSA 

 301-251-7697 
The Commissioners - 2 - 

The staff is currently working to identify high-temperature gas reactor (HTGR) severe accident 

programs through the OECD Task on Advanced Reactor Experimental Facilities (TAREF) 

program. Finally, the staff notes that the industry is responsible for providing the experimental 

data necessary to support the safe design, maintenance, and operation of nuclear power plants. 

Were any data to be identified as important to a safety evaluation for an existing or future plant, 

the industry would be required to provide that information, and the staff would determine the 

need to perform confirmatory research, potentially through a collaborative program. 

BACKGROUND: 

The potential risk to the public from nuclear power generation arises from low-frequency 

accidents that are predicted to progress to the point where fuel degradation occurs and large 

quantities of radioactive material are released to the environment. It is important to NRC’s 

mission that it possess expertise in severe accident phenomenology and a predictive capability 

for simulating the response of nuclear power systems to postulated severe accidents. 

Maintaining expertise in severe accident phenomena to help meet the needs of the agency 

supports continuing some level of severe accident research, even absent specific, immediate, 

regulatory questions. 

NRC has been conducting research on severe accidents for the existing light-water reactors for 

decades and has used the results to inform and improve nuclear power plant risk assessments 

and to improve regulations that in part stem from consideration of severe accidents. In the 

specific area of severe accident risk, research results have been used to refine estimates of 

power plant risk, such as from previously postulated early containment failure mechanisms 

(large-scale steam explosions that fail containment, direct containment heating, and, for largedry containments, hydrogen combustion), showing that these phenomena pose no significant 

contribution to early containment failure and risk. Moreover, research results are being used to 

estimate the offsite consequences of selected severe reactor accidents (State-of-the-Art 

Reactor Consequence Assessment project). Severe accident research has also been used in 

the regulatory framework of design basis events, such as in the development of the alternate 

source term (NUREG-1465, “Accident Source Terms for Light-Water Nuclear Power Plants,” 

February 1995), and to support development of risk-informed regulations, Part 50.44 of Title 10 

of the Code of Federal Regulations, “Combustible gas control for nuclear power reactors.” 

Currently, severe accident analysis methods are being applied to spent fuel pool heat removal 

and to analyses of the dose contribution from boiling-water reactor (BWR) Main Steam Isolation 

Valve leakage. Severe accident information also is regularly used in risk-informed decisions 

that use Regulatory Guide 1.174, “An Approach for Using Probabilistic Risk Assessment in 

Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis”; cost-benefit 

analyses; evaluation of new generic issues; and risk-informed prioritizations. Moreover, the 

information has been used in license renewal applications and in new reactor licensing in 

evaluation of design features to prevent and mitigate severe accidents. 

The regulatory framework has benefitted from the agency’s severe accident research program, 

and the staff continuously evaluates the availability of severe accident research facilities to 

ensure that the agency’s research needs are met. Participation in international cooperative 

programs is an effective means of maintaining access to such facilities. NRC uses seven 

criteria to guide the decisions about participation in international cooperative programs. Those 

criteria were provided to the Commission on December 7, 2007 (“Criteria for Selecting 

International Projects for Cooperation and Participation,” Agencywide Documents Access 
The Commissioners - 3 - 

and Management System ML073300235). The staff has used these criteria to evaluate 

participation in the programs discussed below. In addition, the staff has considered the results 

of international reviews of the issue of world-wide availability of experimental facilities for 

research in areas of importance to the nuclear power industry and concluded that the 

international views are not materially different from its own. In 2002, OECD’s Committee on the 

Safety of Nuclear Installations (CSNI) established a senior group of experts on nuclear safety 

research (SESAR) to assess the need for and strategy of maintaining key research facilities. 

In 2007, OECD published the outcome of the SESAR review in “Nuclear Safety Research in 

OECD Countries: Supporting Facilities for Existing and Advanced Reactors” (SFEAR). The staff 

participated in these activities and considered their findings in the staff’s evaluation of critical 

facilities. 

In addition to its relationship with OECD, NRC has bilateral agreements with many countries. 

One group of bilateral agreements is organized into the Cooperative Severe Accident Research 

Program (CSARP). The participating countries receive NRC’s severe accident code, MELCOR, 

and offsite consequence code, MELCOR Accident Consequence Code System (MACCS2) and, 

in exchange, NRC receives in-kind research in addition to support for code modifications. 

Through some of the CSARP agreements, the NRC receives access to experimental facilities 

and data. 

NRC also cooperates with domestic organizations and has signed a Memorandum of 

Understanding (MOU) with the Electric Power Research Institute (EPRI), which has in the past 

enabled EPRI and NRC to share planning and execution of experimental programs. Recently, 

EPRI and NRC have cooperated on experimental programs such as fuel performance, fire, and 

nondestructive examination. The MOU recognizes the need for NRC to maintain its regulatory 

independence; this has been and will be accomplished by separate interpretation of the results 

or implications of the data derived from the cooperative research programs. Although the 

present program with EPRI does not include severe accident research, the program may be a 

model for industry-regulatory authority cooperation. Lastly, NRC has recently signed an MOU 

with the U.S. Department of Energy (DOE) covering NRC’s participation in the Next Generation 

Nuclear Plant project. The MOU provides for the NRC’s review of DOE’s plans in numerous 

technical areas and for “observation of tests, experiments, simulations, and demonstrations” 

related to those areas. 

DISCUSSION: 

RES continuously evaluates its research programs to ensure they are meeting the needs of the 

agency. These evaluations include consultation with the regulatory offices to help determine the 

need for confirmatory research on current issues under review as well as consultation with the 

domestic and international community to identify opportunities for collaboration. RES also 

considers facility availability in its evaluations. 

RES has found the CSNI SFEAR report to be of use when considering severe accident facility 

availability. The report recommends that the CSNI and the Committee on Nuclear Regulatory 

Activities (CNRA) encourage nuclear industry support of infrastructure preservation by 

emphasizing: 1) the responsibility of industry to develop sufficient data to support their 

applications, 2) the benefits of cooperative research, and 3) the value of preserving critical 

research infrastructure. The factors the SESAR group cites as being important to the ability to 

maintain critical infrastructure include the facility operating and replacement cost, the ability to 
The Commissioners - 4 - 

define a useful experimental program, the long-term resource implications and priorities, the 

industry participation, and the host country’s long-term plans and commitments. NRC maintains 

membership in numerous CSNI and CNRA committees and groups and could be influential in 

the efforts to maintain nuclear industry-unique facilities worldwide, if those facilities were to be 

important to NRC activities. The NRC staff uses the seven criteria discussed previously when 

evaluating participation in such cooperative programs. 

The SFEAR report provides light- and heavy-water-related facility evaluations. At the time the 

document was written, no CSNI recommendations for HTGR facilities were deemed warranted 

because of the early stage of design development. The SFEAR report contains a discussion of 

HTGR issues, based in part on a 1999 OECD conference on “Survey on Basic Studies in the 

Field of High Temperature Engineering,” and in part on a 2002 workshop documented in 

“Advanced Nuclear Reactor Safety Issues and Research Needs.” The scope of the workshop 

included advanced light water reactors and liquid metal reactors, in addition to HTGRs. A new 

CSNI working group, called TAREF, was formed recently to address HTGR facility issues. RES 

is a participant in this effort. 

The SFEAR report identifies the PHEBUS experimental facility in France as a facility of high 

importance to severe accident research. Recently, because of its high cost, the Institut de 

Radioprotection et de Sûreté Nucléaire decided to shut down PHEBUS. Some of its activities 

could be conducted elsewhere in test reactors in the United States, Japan, or Norway, or in the 

future, in France. As the results from the PHEBUS program are analyzed, NRC expects to 

receive additional information on ruthenium behavior that will be of use in the phase behavior 

that will be of importance for reactor accident source term estimation as well as for spent fuel 

pool accident source terms. 

RES evaluated its present programs in severe accident research and has identified nine 

facilities that today substantially contribute to severe accident programs for light-water reactor 

technology (the staff is in the process of reviewing facilities important to advanced reactor 

technologies). Each program is briefly described below. Some are important to retain for the 

NRC’s long-term program and others will be reevaluated for long-term support at the end of the 

current program. 

The following provides the programs likely to require long-term support, the host country, and 

the program through which NRC participates: 

• VERDON, France, is a bilateral agreement through the International Source Term 

Program (ISTP), and studies the fission product behavior in containment. This 

experimental facility will provide data to validate fission product release models under 

steam/hydrogen mixture or air-ingress conditions. 

• Two facilities, KROTOS, France, and Test for Real cOrium Interaction (TROI), Korea, 

are part of the OECD’s Steam Explosion Resolution for Nuclear Applications (SERENA) 

program. SERENA is quantifying the effects of voiding on ex-vessel steam explosion 

potential and energetics to bound the calculated pressure-time history and loads on 

structures. These facilities can also support experimental programs on fuel-coolant 

interaction. The need to maintain two facilities will be reevaluated at the end of 

SERENA, but it is likely that support for at least one will continue. 
The Commissioners - 5 - 

The facilities for which the long-term support will be evaluated at the completion of the present 

program are: 

• AeRosol Trapping In a STeam Generator (ARTIST), Switzerland, is a bilateral 

agreement, involving studies of aerosol behavior in the secondary side of a steam 

generator and separate effects in piping. Results from the current research will allow 

NRC to improve source term bypass models and evaluate fission product resuspension. 

• QUENCH, Germany, is a bilateral agreement through CSARP, which studies the 

effectiveness of core melt prevention scenarios. This research will provide data to 

evaluate success criteria in severe accident analyses under over-heated fuel conditions. 

• Experimental Programme of Iodine Chemistry Under Radiation (EPICUR), France, is a 

bilateral agreement through ISTP, which studies iodine behavior in containment. This 

research will address uncertainties related to iodine interactions with paints and the need 

for pH control in the containment sump. 

• CHemistry of Iodine Project (CHIP), France, is a bilateral agreement through ISTP, 

which studies iodine chemistry in the reactor coolant system. This program is evaluating 

the potential for release of gaseous iodine into the containment, for instance from 

revaporization from surfaces. 

• Behavior of Iodine Project (BIP), Canada, is a bilateral agreement through OECD, which 

studies iodine behavior. This research will quantify various processes on surfaces 

leading to gaseous iodine formation; measure adsorption/desorption rate constants on 

containment surfaces as a function of temperature, relative humidity, and carrier-gas 

composition in humid environments; and measure absorption of iodine on sump 

materials. 

• Melt Coolability and Concrete Interaction (MCCI), United States, is an OECD program 

hosted by the NRC, which studies ex-vessel core-concrete interactions using prototypic 

materials in a large scale facility. The program is acquiring data to improve our 

understanding of certain phenomena and to support model development for special 

mitigation features intended to protect the bottom-cooled basemats of the European 

Pressurized Reactor and the Economic Simplified Boiling Water Reactor. 

The NRC does not have active programs at any of the three following facilities, but they may 

become more important in the future to support licensing review activities. 

• Thermal Hydraulics, Aerosols and Iodine (THAI), Germany, presently evaluates thermalhydraulic and aerosol behavior in containment. The facility may be of use in the future to 

study graphite dust in HTGRs. 

• Molten Fuel Moderator Interaction (MFMI), Canada, studies core disassembly and fuel 

channel safety for Canadian-designed reactors. This facility could be important to NRC 

if design certification is sought for an Advanced Canadian Reactor (ACR). 
The Commissioners - 6 - 

• The Natural Convection Shutdown Heat Removal Test Facility (NSTF), United States, is 

a large-scale facility designed to investigate HTGR reactor cavity cooling system 

performance under severe accident conditions. 

Severe accident experimental research, as typified by the work in the facilities discussed above, 

is expensive because the facilities must operate under challenging conditions. In addition, 

facilities that use radioactive materials are especially expensive because of material control 

requirements. The expense has fostered the international cooperation discussed above 

because each country with interests in the area has recognized that it cannot afford to provide 

the necessary funding solely from its own budget. 

For the nine facilities with active programs, RES has budgeted a total of $1.2M in fiscal year 

(FY) 2009 and $1.1M in FY 2010. Each of the cooperative programs is covered by a detailed 

bilateral or multilateral agreement and has been evaluated to ensure that the program complies 

with the seven criteria and is cost-beneficial to the agency. Nonetheless, NRC does not know in 

all cases how much money or in-kind research is provided to the program by third parties so the 

total cost is not known for every program. However, for those programs where NRC does know 

the cost, NRC’s share is about 10 percent where the United States is not the host country, or 

could be as high as 50 percent where the United States is the host country. Because of their 

high costs, experimental programs are highly leveraged in the international community and have 

been for many years. However, because of their long lead times for planning, procurement, and 

analysis, experimental programs require multiyear funding support from the participants. 

RECOMMENDATION: 

The staff recommends that the Commission agree that the staff continue to negotiate bilateral 

and multilateral agreements for light-water reactor and high-temperature gas reactor 

experimental programs to meet the needs of the agency. 

COORDINATION: 

The Office of the General Counsel reviewed this paper and has no legal objection. 

 /RA Martin J. Virgilio For/ 

 R. W. Borchardt 

 Executive Director 

 for Operations 
The Commissioners - 6 - 

• The Natural Convection Shutdown Heat Removal Test Facility (NSTF), United States, is 

a large-scale facility designed to investigate HTGR reactor cavity cooling system 

performance under severe accident conditions. 

Severe accident experimental research, as typified by the work in the facilities discussed above, 

is expensive because the facilities must operate under challenging conditions. In addition, 

facilities that use radioactive materials are especially expensive because of material control 

requirements. The expense has fostered the international cooperation discussed above 

because each country with interests in the area has recognized that it cannot afford to provide 

the necessary funding solely from its own budget. 

For the nine facilities with active programs, RES has budgeted a total of $1.2M in fiscal year 

(FY) 2009 and $1.1M in FY 2010. Each of the cooperative programs is covered by a detailed 

bilateral or multilateral agreement and has been evaluated to ensure that the program complies 

with the seven criteria and is cost-beneficial to the agency. Nonetheless, NRC does not know in 

all cases how much money or in-kind research is provided to the program by third parties so the 

total cost is not known for every program. However, for those programs where NRC does know 

the cost, NRC’s share is about 10 percent where the United States is not the host country, or 

could be as high as 50 percent where the United States is the host country. Because of their 

high costs, experimental programs are highly leveraged in the international community and have 

been for many years. However, because of their long lead times for planning, procurement, and 

analysis, experimental programs require multiyear funding support from the participants. 

RECOMMENDATION: 

The staff recommends that the Commission agree that the staff continue to negotiate bilateral 

and multilateral agreements for light-water reactor and high-temperature gas reactor 

experimental programs to meet the needs of the agency. 

COORDINATION: 

The Office of the General Counsel reviewed this paper and has no legal objection. 

 /RA Martin J. Virgilio For/ 

 R. W. Borchardt 

 Executive Director 

 for Operations 

ADAMS Accession No.: ML083380047 WITS 200800188/EDATS: SECY-2008-0207 

OFFICE RES/DSA BC: DSA/NARB BC: DSA/FSTB BC: DSA/RSAB Tech Editor 

NAME JMitchell JJolicoeur RLee MGavrilas JZabel (via email)

DATE 12/10/08 12/17/08 12/16/08 12/11/08 12/15/08 

OFFICE D: RES/DSA NSIR NRR NRO FSME 

NAME JUhle WDean JGrobe CAder (via email) DCool (via email)

DATE 12/10/08 12/19/08 12/18/08 12/16/08 12/15/08 

OFFICE OGC D: RES EDO 

NAME KWinsberg BSheron (JLyons for) RBorchardt 

(MVirgilio for)

 

DATE 12/15/08 12/30/08 01/08/09 

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