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in creator/contributor: "Schaefer, R. W."

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ZPR-6 Assembly 7 High {Sup 240} Pu Core : A Cylindrical Assemby With Mixed (Pu, U)-Oxide Fuel and a Central High {Sup 240} Pu Zone.

Over a period of 30 years more than a hundred Zero Power Reactor (ZPR) critical assemblies were constructed at Argonne National Laboratory. The ZPR facilities, ZPR-3, ZPR-6, ZPR-9 and ZPPR, were all fast critical assembly facilities. The ZPR critical assemblies were constructed to support fast reactor development, but data from some of these assemblies are also well suited to form the basis for criticality safety benchmarks. Of the three classes of ZPR assemblies, engineering mockups, engineeri… more

Date: October 1, 2007

Creator: Lell, R. M.; Schaefer, R. W.; McKnight, R. D.; Tsiboulia, A.; Rozhikhin, Y.; Division, Nuclear Engineering et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Advances in criticality predictions for EBR-II

Improvements to startup criticality predictions for the EBR-II reactor have been made. More exact calculational models, methods and data are now used, and better procedures for obtaining experimental data that enter into the prediction are in place. Accuracy improved by more than a factor of two and the largest ECP error observed since the changes is only 18 cents. An experimental method using subcritical counts is also being implemented.

Date: March 1, 1994

Creator: Schaefer, R. W. & Imel, G. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ZPR-3 Assembly 6f : A Spherical Assembly of Highly Enriched Uranium, Depleted Uranium, Aluminum and Steel With an Average {Sup 235}U Enrichment of 47 Atom %.

Over a period of 30 years, more than a hundred Zero Power Reactor (ZPR) critical assemblies were constructed at Argonne National Laboratory. The ZPR facilities, ZPR-3, ZPR-6, ZPR-9 and ZPPR, were all fast critical assembly facilities. The ZPR critical assemblies were constructed to support fast reactor development, but data from some of these assemblies are also well suited for nuclear data validation and to form the basis for criticality safety benchmarks. A number of the Argonne ZPR/ZPPR crit… more

Date: September 30, 2010

Creator: Lell, R. M.; McKnight, R. D; Schaefer, R. W. & Division, Nuclear Engineering

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Probabilistic treatment of rod run-in accident initiators and the reactivity feedback responses in EBR-II

The idea of treating an accident initiator in a probabilistic manner is developed. Instead of using a bounding value, the rod reactivity insertion in an unprotected transient overpower accident is described realistically as a distribution of insertion magnitudes. The initiator analysis uses EBR-II Operating Instructions and data files of rod worths and position histories. The average insertion magnitude is found to be 16{cents}, which is only about hall of the feedback reactivity from zero to f… more

Date: December 31, 1993

Creator: Schaefer, R. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fissile sample worths in the Uranium/Iron Benchmark

One of the long-standing problems from LMFBR critical experiments is the central worth discrepancy, the consistent overprediction of the reactivity associated with introducing a small material sample near the center of an assembly. Reactivity (sample worth) experiments in ZPR-9, assembly 34, the Uranium/Iron Benchmark (U/Fe), were aimed at investigating this discrepancy. U/Fe had a large, single-region core whose neutronics was governed almost entirely by /sup 235/U and iron. The essentially on… more

Date: January 1, 1983

Creator: Schaefer, R. W. & Bucher, R. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fixed-source perturbation worth calculations

Material worth measurements are routinely performed in fast reactor critical programs. Until recently, such measurements were usually made by inserting cylindrical samples via stainless steel tubes. Such measurements pose difficult problems for the analyst since the geometry is very complicated. An alternative measurement utilizes a drawer oscillator to remove or insert a fuel plate. In such a measurement, samples are large enough to cause significant distortions of the local flux. Consequently… more

Date: January 1, 1984

Creator: Smith, K. S. & Schaefer, R. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Criticality safety issues in the disposition of BN-350 spent fuel

A criticality safety analysis has been performed as part of the BN-350 spent fuel disposition project being conducted jointly by the DOE and Kazakhstan. The Kazakhstan regulations are reasonably consistent with those of the DOE. The high enrichment and severe undermoderation of this fast reactor fuel has significant criticality safety consequences. A detailed modeling approach was used that showed some configurations to be safe that otherwise would be rejected. Reasonable requirements for desig… more

Date: February 28, 2000

Creator: Schaefer, R. W.; Klann, R. T.; Koltyshev, S. M. & Krechetov, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Utilizing benchmark data from the ANL-ZPR diagnostic cores program

The support of the criticality safety community is allowing the production of benchmark descriptions of several assemblies from the ZPR Diagnostic Cores Program. The assemblies have high sensitivities to nuclear data for a few isotopes. This can highlight limitations in nuclear data for selected nuclides or in standard methods used to treat these data. The present work extends the use of the simplified model of the U9 benchmark assembly beyond the validation of k{sub eff}. Further simplificatio… more

Date: February 15, 2000

Creator: Schaefer, R. W. & McKnight, R. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department