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in creator/contributor: "Rest, J."

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Development and experimental verification of SST-GRASS: a steady-state and transient fuel response and fission-product release code. [BWR; PWR]

A comprehensive fission-product release model (GRASS), based on a mechanistic understanding of fuel behavior in LWR fuel elements for a wide range of accidental overheating conditions as well as steady-state irradiations, is being developed at Argonne National Laboratory. Experimental support for GRASS is provided by out-of-reactor transient heating of irradiated commercial LWR fuel using a direct-electrical-heating technique. The GRASS calculations are described, benchmarked against standard t… more

Date: January 1, 1976

Creator: Rest, J.; Seitz, M. G.; Gehl, S. M. & Kelman, L. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fastgrass: A Mechanistic Model for the Prediction of Xe, I, Cs, Te, Ba, and Sr Release From Nuclear Fuel Under Normal and Severe-Accident Conditions

The primary physical/chemical models that form the basis of the FASTGRASS mechanistic computer model for calculating fission-product release from nuclear fuel are described. Calculated results are compared with test data and the major mechanisms affecting the transport of fission products during steady-state and accident conditions are identified.

Date: September 1, 1992

Creator: Rest, J. & Zawadzki, S. A. (Argonne National Lab., IL (United States))

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Development and verification of the LIFE-GCFR computer code for predicting gas-cooled fast-reactor fuel-rod performance

The fuel-pin modeling code LIFE-GCFR has been developed to predict the thermal, mechanical, and fission-gas behavior of a Gas-Cooled Fast Reactor (GCFR) fuel rod under normal operating conditions. It consists of three major components: thermal, mechanical, and fission-gas analysis. The thermal analysis includes calculations of coolant, cladding, and fuel temperature; fuel densification; pore migration; fuel grain growth; and plenum pressure. Fuel mechanical analysis includes thermal expansion, … more

Date: March 1, 1982

Creator: Hsieh, T. C.; Billone, M. C. & Rest, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A mechanistic model for radiation-induced crystallization and amorphization in U{sub 3}Si

Radiation-induced amorphization is assessed. A rate-theory model is formulated wherein amorphous clusters are formed by the damage event These clusters are considered centers of expansion (CE), or excess-free-volume zones. Simultaneously, centers of compression (CC) are created in the material. The CCs are local regions of increased density that travel through the material as an elastic (e.g., acoustic) shock wave. The CEs can be annihilated upon contact with CCs (annihilation probability depen… more

Date: June 1, 1994

Creator: Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fission gas bubble nucleated cavitational swelling of the alpha-uranium phase of irradiated U-Pu-Zr fuel

Cavitational swelling has been identified as a potential swelling mechanism for the alpha uranium phase of irradiated U-Pu-Zr metal fuels for the Integral Fast Reactor being developed at Argonne National Laboratory. The trends of U-Pu-Zr swelling data prior to fuel cladding contact can be interpreted in terms of unrestrained cavitational driven swelling. It is theorized that the swelling mechanisms at work in the alpha uranium phase can be modeled by single vacancy and single interstitial kinet… more

Date: April 1, 1992

Creator: Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Comparison of irradiation behavior of different uranium silicide dispersion fuel element designs

Calculations of fuel swelling of U{sub 3}SiAl-Al and U{sub 3}Si{sub 2} were performed for various dispersion fuel element designs. Breakaway swelling criteria in the form of critical fuel volume fractions were derived with data obtained from U{sub 3}SiAl-Al plate irradiations. The results of the analysis show that rod-type elements remain well below the pillowing threshold. However, tubular fuel elements, which behave essentially like plates, will likely develop pillows or blisters at around 90… more

Date: January 1, 1995

Creator: Hofman, G. L.; Rest, J. & Snelgrove, J. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A New Swelling Model and Its Application to Uranium Silicide Research Reactor Fuel

This document discusses a new version of the dispersion fuel behavior model currently being incorporated in DART, which has been generated. The model`s description of fuel swelling - more specifically, the evaluation of fission-gas bubble morphology - is significantly improved. Although some of the assumptions underlying the basic model are derived from systems other than U{sub 3}Si{sub 2}, it represents a physically realistic interpretation of the observed irradiation behavior of U{sub 3}Si{su… more

Date: December 31, 1992

Creator: Hofman, G. L.; Rest, J. & Snelgrove, J. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A phenomenological model for the effect of nanocrystalline microstructure on irradiation-induced amorphization in U{sub 3}Si

A rate theory model is formulated wherein amorphous clusters are formed by a damage event. These clusters are considered centers of expansion (CEs), or excess-free-volume zones. Simultaneously, centers of compression (CCs) are created in the material. The CCs are local regions of increased density that travel through the material as an elastic (e.g., acoustic) shock wave. The CEs can be annihilated upon contact with a sufficient number of CCs, to form either a crystallized region indistinguisha… more

Date: October 1, 1994

Creator: Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Predicted irradiation behavior of U sub 3 O sub 8 -Al dispersion fuels for production reactor applications

Candidate fuels for the new heavy-water production reactor include uranium/aluminum alloy and U{sub 3}O{sub 8}--Al dispersion fuels. The U{sub 3}O{sub 8}--Al dispersion fuel would make possible higher uranium loadings and would facilitate uranium recycle. Research efforts on U{sub 3}O{sub 8}--Al fuel include in-pile irradiation studies and development of analytical tools to characterize the behavior of dispersion fuels at high-burnup. In this paper the irradiation performance of U{sub 3}O{sub 8… more

Date: January 1, 1990

Creator: Cronenberg, A.W. (Engineering Science and Analysis, Albuquerque, NM (USA)); Rest, J. (Argonne National Lab., IL (USA)); Hyder, M.L.; Morin, J.P. & Peacock, H.B. (Westinghouse Savannah River Co., Aiken, SC (USA))

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Volatile fission-product source term evaluation using the fastgrass comptuer code. [PWR; BWR]

As the noble gases play a major role in establishing the interconnection of escape routes from the interior to the exterior of nuclear reactor fuel, a realistic description of the release of volatile fission products (VFPs) must a priori include a realistic description of fission-gas release and swelling. The steady-state and transient gas release and swelling subroutine, FASTGRASS, has been modified to include a mechanistic description of behavior of VFPs (I, Cs, CsI, Cs/sub 2/MoO/sub 4/, and … more

Date: August 1, 1982

Creator: Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Steady-state and transient fission gas release and swelling model for LIFE-4. [LMFBR]

The fuel-pin modeling code LIFE-4 and the mechanistic fission gas behavior model FASTGRASS have been coupled and verified against gas release data from mixed-oxide fuels which were transient tested in the TREAT reactor. Design of the interface between LIFE-4 and FASTGRASS is based on an earlier coupling between an LWR version of LIFE and the GRASS-SST code. Fission gas behavior can significantly affect steady-state and transient fuel performance. FASTGRASS treats fission gas release and swellin… more

Date: June 1, 1984

Creator: Villalobos, A.; Liu, Y. Y. & Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Study of UO/sub 2/ wafer fuel for very high-power research reactors

The Reduced Enrichment Research and Test Reactor Program is aimed at reducing fuel enrichment to < 20% in those research and test reactors presently using highly enriched uranium fuel. UO/sub 2/ caramel fuel is one of the most promising new types of reduced-enrichment fuel for use in research reactors with very high power density. Parametric studies have been carried out to determine the maximum specific power attainable without significant fission-gas release for UO/sub 2/ wafers ranging from … more

Date: November 1, 1980

Creator: Hsieh, T.C.; Jankus, V.Z.; Rest, J. & Billone, M.C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Isotopic fission product release from nuclear fuel under severe core damage accident conditions

Isotopic fission gas release behavior during SFD tests 1-1, 1-3, and 1-4 is strongly dependent on the pre-test fuel history. For SFD 1-1, where the majority of all the fission products were generated during the preconditioning period, very little difference in isotopic release behavior between short- and long-lived species is predicted. For the SFD 1-3 and 1-4 tests, where the majority of all short-lived fission gases decayed away during the 4-year cooling period, differences between the behavi… more

Date: September 1, 1985

Creator: Rest, J.; Osetek, D. J. & Hartwell, J. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Analysis of in-situ tritium recovery from solid fusion-reactor blankets

The proposed concept for in-situ tritium recovery from the STARFIRE blanket involves circulation of a low pressure (approx. 0.05 MPa) helium through formed channels in the highly porous solid breeding material. Tritium generated within the grains must diffuse to the grain boundaries, migrate through the grain boundaries to the particle surface and then percolate through the packed bed to the helium purge channel. Highly porous ..cap alpha..-LiAlO/sub 2/ with a bimodal pore distribution is propo… more

Date: January 1, 1980

Creator: Smith, D. L.; Clemmer, R. G.; Jankus, V. Z. & Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The effect of crystal structure stability on the mobility of gas bubbles in intermetallic uranium compounds

Irradiation experiments with certain low-enrichment, high-density, uranium-base intermetallic alloys that are candidate reactor fuel materials, such as U/sub 3/Si and U/sub 6/Fe, have revealed extraordinarily large voids at low and medium fuel burnup. This phenomenon of breakaway swelling does not occur in other fuel types, such as U/sub 3/Si/sub 2/ and UAl/sub 3/, where a distribution of relatively small and stable fission gas bubbles forms. In situ transmission electron microscope observation… more

Date: January 1, 1988

Creator: Rest, J.; Hofman, G. L. & Birtcher, R. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanistic prediction of transient fission-gas release from LWR fuel. [UO/sub 2/]

The steady-state and transient gas release and swelling subroutine (GRASS-SST) is a mechanistic computer code for the prediction of fission-gas behavior in UO/sub 2/-base fuels. GRASS-SST treats fission-gas release and fuel swelling on an equal basis and simultaneously treats all major mechanisms that influence fission-gas behavior. The GRASS-SST transient analysis has evolved through comparisons of code predictions with the fission-gas release and physical phenomena that occur during reactor o… more

Date: January 1, 1978

Creator: Rest, J. & Gehl, S.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A new swelling model and its application to uranium silicide research reactor fuel

This document discusses a new version of the dispersion fuel behavior model currently being incorporated in DART, which has been generated. The model's description of fuel swelling - more specifically, the evaluation of fission-gas bubble morphology - is significantly improved. Although some of the assumptions underlying the basic model are derived from systems other than U[sub 3]Si[sub 2], it represents a physically realistic interpretation of the observed irradiation behavior of U[sub 3]Si[su… more

Date: January 1, 1992

Creator: Hofman, G.L.; Rest, J. & Snelgrove, J.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanistic prediction of iodine and cesium release from LWR fuel

A theoretical model (FASTGRASS) has been used for predicting the behavior of fission gas and volatile fission products (VFPs) in UO/sub 2/-base fuels during steady-state and transient conditions. This model represents an attempt to develop an efficient predictive capability for the full range of possible reactor operating conditions. Fission products released from the fuel are assumed to reach the fuel surface by successively diffusing (via atomic and gas-bubble mobility) from the grains to gra… more

Date: December 1, 1983

Creator: Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Grain boundary sweeping and dissolution effects on fission product behavior under severe fuel damage accident conditions

The theoretical FASTGRASS-VFP model has been used in the interpretation of fission gas, iodine, tellurium, and cesium release from severe-fuel-damage (SFD) tests performed in the PBF reactor in Idaho. A theory of grain boundary sweeping of gas bubbles, gas bubble behavior during fuel liquefaction (destruction of grain boundaries due to formation of a U-rich melt phase), and during U-Zr eutectic melting has been included within the FASTGRASS-VFP formalism. The grain-boundary-sweeping theory cons… more

Date: October 1, 1985

Creator: Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanistic model for Sr and Ba release from severely damaged fuel

Among radionuclides associated with fission product release during severe accidents, the primary ones with health consequences are the volatile species of I, Te, and Cs, and the next most important are Sr, Ba, and Ru. Considerable progress has been made in the mechanistic understanding of I, Cs, Te, and noble gas release; however, no capability presently exists for estimating the release of Sr, Ba, and Ru. This paper presents a description of the primary physical/chemical models recently incorp… more

Date: November 1, 1985

Creator: Rest, J. & Cronenberg, A.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Scoping analysis of fission gas behavior in UO/sub 2/ fuel for an in-core thermionic reactor

This paper gives results from a preliminary evaluation of swelling, and, in particular, swelling caused by the retained fission gases (Xe, Kr) in the fuel. Design parameters of the thermionic unit cell and its operating conditions were provided by Space Power, Inc. The analysis tool used is a mechanistic fission-gas behavior code, FASTGRASS, developed by J. Rest at ANL (Rest, 1984). In the FASTGRASS analysis, the UO/sub 2/ fuel column is taken as a solid cylinder. No external restraint is impos… more

Date: October 1, 1984

Creator: Liu, Y. Y. & Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanistic prediction of fission-gas behavior during in-cell transient heating tests on LWR fuel using the GRASS-SST and FASTGRASS computer codes

GRASS-SST and FASTGRASS are mechanistic computer codes for predicting fission-gas behavior in UO/sub 2/-base fuels during steady-state and transient conditions. FASTGRASS was developed in order to satisfy the need for a fast-running alternative to GRASS-SST. Althrough based on GRASS-SST, FASTGRASS is approximately an order of magnitude quicker in execution. The GRASS-SST transient analysis has evolved through comparisons of code predictions with the fission-gas release and physical phenomena th… more

Date: January 1, 1979

Creator: Rest, J. & Gehl, S.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Prediction of the response of fission-gas in nuclear fuels during normal and transient heating conditions

A discussion is presented on the interplay between mechanisms of fission-gas behavior, and on how the assumed relationships between various mechanisms affect predictions for the behavior of the gas during a wide range of operating conditions. Highlighted in the discussion are the relationships between intragranular fission gas mobilities during normal and off-normal (nonequilibrium) conditions and intra- and intergranular gas-atom re-solution. The main conclusion reached is that more definitive… more

Date: January 1, 1979

Creator: Rest, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

GCFR Fuels and Materials Program at Argonne National Laboratory

The F-5 fuel-pin irradiation experiment in EBR-II is a cornerstone of the GCFR program. It is the largest-scale fuel-pin experiment in the present program and will provide data on the performance of pins and a pin-support structure that are prototypic of the GCFR Demonstration Plant. The fuel pins are presently undergoing interim examination after successfully achieving 4.6 at.% burnup. Studies of the thermodynamics and kinetics of the U--Cs--O system, supplemented by analysis of the results of… more

Date: January 1, 1979

Creator: Neimark, L. A.; Greenberg, S.; Johnson, C. E.; Purohit, A.; Liu, Y. Y.; Rest, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department