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'U SY PEMORANDUM FOR:
Victor Stello, Jr.
Executive Director for Operations FROM:
Eric 5. Beckjord, Director Office.cf Nuclear Regulatory Research
SUBJECT:
EXCHANGE AND DISTRIBUTION OF NRC COMPUTER CODES THROUGH INTERNATIONAL AGREEMENTS AhD OTHER MEANS The purpose of this memorandum is to describe in some detail the considerations used in transferring and exchanging of computcr codes as part of nuclear safety research international agreements. The discussion is separated into two parts to address the specific IAEA Source Tem Code Package transfer (Enclosure 1) and code transfer and exchange in general (Enclosures 2,3,4).
includes a general list of codes which have been involved in exchange agreements with others.
International cooperative agreements in the area of thermal-hydraulic code assessment and severe accidents and source tenn research which involve a number of computer code transfer and/or exchanges are used to illustrate the manner in which computer codes are exchanced or transferred as part of our international agreement.
The Office of Nuclear Regulatory Research presently has a large number of international agreements with research institutions around the world. A number these agreements are based on the transfer of codes developed under either total or partial NRC sponsorship. These codes range from simple, single purpose codes to large multi-purpose codes used in the evaluation of nuclear power plant safety systems and components.
I.
Source Term Code Package to the IAEA Recently, Chairman Zech provided the IAEA a set of internally consistent, interfacing computer codes for assessing the release of radioactive materials from a light water (PWR 8 BWR) nuclear reactor accident to the environment.
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These endes designated by the NRC as the Source Term Code Package ($TCP) are a
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listed below and are further described by the charts in Enclosure 1.
oE PARCH - describes the overall behavior of the reactor coolant system, y[g molten core, and containment.
MERGE - describes detailed temperature, pressure, and flow in the reactor coolant system, SEE
- 3 CORCON - describes detailed core-concrete temperature and interactions.
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. 0 4EN - describes fission product inventory in fuel,
@@g CORSOR 1 de. scribes fission product releases from the fuel.
NA
Victor Stello, Jr.
2 OCT 2 1986 TRAPMELT - describes reactor coolant system transport and retention, VANESA - describes fission product releases from core-concrete melt,
!!AUA - describes aerosol deposition of fission products in the containment, SPARC - describes fission product retention in water pools, and ICEDF - describes fission product retention in ice condensers.
The use and application of these codes are fully described in Reassessment of the Technical Bases for Estimating Source Terms. NUREG-0956 and its companion Source Term Code Package docunent, HUREG/CR-4587. Both have been recently published and made available to the general public. This code package has been developed as part of the NRC severe accident and source tem program in which foreign governments have nade significant contributions in terms of financial ano scientific manpower resources through international cooperative This agreements with the USNRC as indicated in the attachment to Enclosure 2.
financial and technical support for this program by several countries with substantial nuclear programs has resulted in mutual benefits for all.
Assuming that the lAEA will devote the necessary resources, we believe that these codes have the potential for a broader range of applications and they could be modified to assess the accident behavior of nuclear power reactors types other than LWRs.
These codes developed under the USNRC sponsored program are available on request to US industry since the NRC coordinated closely with the Industry Degraded Core Study Group (IDCOR) during the source tem reevaluation progran.
The NRC has not utilized IDCOR developed codes, but the codes could be made available on request. However, NRC has reviewed the IDCOR code documentation.
RES believes that because of the specific safety nature of the STCP codes these codes bave no intrinsic military value or application.
II. NRC Computer Cnde Exchange in General As noted above, in the last few years the NRC has entered into a number of international agreements involving the transfer of codes as part of the cooperation. Foreign research groups doing nuclear safety studies continue to have a high degree of interest in NRC developed codes. Until very recently, most of the nuclear power plants licensed abroad used hRC developed licensing requirements and procedures.
The need to perfom their own safety analysis coupled with the clear leadership enjoyed by the US software developers, has prompted many research groups to adapt US codes to their analytical needs and apply the US codes to address their nuclear safety evaluations. As noted in, RES presently has a number of agreements in which codes are specifically exchanged.
In some cases foreign groups have requested us to perfom some of their reactor safety analysis and have agreed not only to pay
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Victor Stello, Jr.
3 OCT 2 1985
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for these calculations but also to pay the NRC to maintain and upgrade these cedes for specific applications. An example of this situation is the current negotiation with Japan, Germany, and France to upgrade a module of the SIMMER 11 code used in the analysis of core melt accidents by developing an advanced fluid dynamics model.
Under this arrangement the NRC will pey for less than 1/5 the cost of the total effort and get the benefit of the whole program.
Specife code exchange agreements in which the NRC gains e tremendcus leverage is in the area of thennal hydraulic code assessment. The USNRC has invested substantial sums of money to develop thermal hydraulic codes such as RELAP and TRAC and other codes listed in Enclesure 3 to calculate thermal hydraulic transients analysis.
The present NRC budget does not provide the necessary funds to assess these codes or to develop the necessary data needed for code assessment. Many of these assessment are being conducted through a series of international agreements as shown in the attachment to Enclosure 2, in which, basically, the USNRC provides the uther party with codes plus instructions on their use; the other party performs assessment based on thermal hydraulic transients and/or experimental conditions of mutual interest to the parties.
In the area of severe fuel damage, severe accidents and source tenn analysis, which were discussed above in connection with the transfer of the Source Tenn Code Package to the IAEA, the transfer of NRC codes has been an integral part of these foreign cooperative agreenents.
In this case, foreign funds have been provided to RES and have been used to perform additional in-pile fuel damage experiments. These experiments have been used to verify and or calibrate analytical techniques to predict the behavior of severely damaged fuel under controlled experimental conditions. These experiments conducted in various US and Canadian test reactors and partly paid with foreign funds have provided the NRC with the necessary data to validate a number of codes such as, SCDAP/RELAP, TRAP-MELT, FASTGRASS and others as described in Enclosure 4.
l The area of thermal hydraulic code assessment and severe accident program l
l exchanges serve to illustrate the manner and philosophy used in transfering computer codes as a means of cooperation with other countries. In terms of the procedures used to insure an equitable return for the NRC codes, all bilateral l
agreements cell for periodic reviews of the work in progress and in the case of severe accidents and thermal hydraulic code assessment agreements, semiannual meetings both here and abroad are held in which all the participants not only attend but present their findings.. For example, on October 21-24, 1986 the severe accident cooperative group will have its semiannual meeting in Washington, D.C.
On November 1,1986, the thermal hydraulic International Code Assessment Program (ICAP) group will hold its third semiannual review meeting in Washington, D.C.
We expect these meetings to provide valuable contributions to safety research in their respective areas.
In addition to periodic reviews in which information is exchanged, the agreements have clauses which limit and specify the use and application of these codes by a third party and restricts the use of NRC codes to solely
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nuclear safety studies and licensing activities of the other party.
In all
Victor Stello, Jr.
4 g7 2 566 cases where codes are exchanged, the other party agrets to provide the NRC with results of the code applications and updates to the subject codes.
i In most cases the international agreements involve new codes or codes under development which have not yet been fully verified and or documented and are not available to the Argonne National Laboratory Code Center. However, in sone cases some countries have requested to enter into an agreement, even when codes are publically available, for them to obtain aid and assistance in the use of these codes. Obviously, the trade value of codes which are already in the public domain is limited and, for this reason, we concentrate our international agreements on codes which are not fully verified and in need of further development.
It is this category of codes which are mostly sought by foreign research groups. At the same time, these codes under development have been inade available to the U.S. nuclear industry and other domestic institutions through separate arrangements with the NRC. The US vendors are presently using some of these codes and or versions of these codes as their best estimate tools in licensing submittels.
For example EXXON uses TRAC-PWR, GE uses TRAC-BWR,.
k'estinghouse uses COBRA / TRAC and B&W is using RELAP5 MOD 2.
l lists other NRC codes used in the regulatory process which have been involved in exchange agreements with others. As can be seen by this list, the number, name and nature of computer codes is a variable depending on the use and application. Code developers are constantly improving their products and/or changing the range of application and in the process redefining their codes in such a way as to make it very difficult if not impossible to state at any given time what codes are available and under what conditions can a given code be transferred or exchanged and for what.
In cooperative agreements involving code, we are always careful t6 note not only the code version but its
, intended application as part of the agreement.
I hope this perncrandum answers the questions associated with the recent Source Term. Code Package transfer to the IAEA, as wc11 as specify the broad policy of the office in this regard.
DISTRIBUTION: RHoskins sub,)
RES Div. Dirs
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chron RES Dep. Dirs circ RHauber, IP EBeckjord Eric S. Beckjord, Director DFRoss Office of Nuclear Regulatory Research JCortez
Enclosures:
As stated RES Div. Dirs
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