Residual and fission gas release from UOg were studied in the laboratory and in in-reactor experiments. Arc-fused powder and sintered pellets were used to determine the rate of evolution and types of residual gases as a function of temperature.Fission gas release was related to the average UO2 temperature prevalent iri fuel elements studied during irradiation. The UOg temperature and fission gas release calculations were made using the latest thermal conductivity values, isotopic half lives, and branching ratios available m the literature. The results obtained were compared with those available in the literature, and a satisfactory agreement was found among the groups of comparable data.

This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Make& Any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of th" huormatlnn contained in this report, or that the use of any luformnttnn , apparatus, method, or process disclosed in this report way not Infringe privately owned rlghto; or B. Assumes any liabilities with respect to the us" uf, or for tlAma~tes re~:~u!tlu~ from thP use of any Information, apparatus, method, or process disclosed In this report. As used In the above, "person acting on behalf of the Commission" Includes any employee or contractor of the Commission, or employee of such contractor, to the extent that Ruch employee or contractor of the Commission, ur employee of such contractor prepares, disseminates, or provide~:~ access to, any Information pursuant to his employment or contract with the Commission, or his employment with such contractor. This report has been reproduced directly from the best available copy.

LN·l LEGAL NOTICEThis report was prepared as an account of Government sponsored work. Neither the United Slates, n(!r the Commission, nor any pe,.son a~ting on behalf of the Commission: A. Makes any warranty or representation, .expressed or implied, with respe~t to the at~ura~y, completeness, or usefulness of the information ~ontained in this report, or thallhe use of any information, apparatus, method, or pro~ess disclosed in this report may not infringe privately owned-rights; (!r B. Assumes any liabilities with respe~t io the use of; or for damages resulting from the use of any information, apparatus, method, or pro~ess dis~losed in this report.· As used in the above, "person acting on behalf of the Commission" includes any employee or contra~tor of the Commission, or em· ployee of such contractor, to the extent that such employee or contractor of the Commission, or employee of su~h contractor prepares, disseminates, or provides a~cess to, any information pursuant to his employment or ~ontract with the Commission, or bis employment with su~h contractor. y I -:• GEAP-4013 ABSTRACT Control rod materials, designs, and fabrication processes are compared for their relative economies. Control rod lifetime data are calculated with a simple approximation of nuclear worth depreciation.These data are used in conjunction with the estimated fabrication costs to determine the cost of using several absorber materials in a typical power reactor on a cost-per-year basis. The effect the control system has on core power density and fuel lifetime is included. ACKNOWLEDGMENTThe authors are indebted to A. J. Alexander for his help in estimating the costs for the various fabrication processes evaluated in this study.

This report was prepared ns an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting o~ behalf of the CommJsslon: A. Makes any warranty or representation, expressed or implied, with respect to the ac.cur.O.cy, completeness, or usefulness of the Information contained In this report, or that the use of any Information, apparatus, method, or process disclosed in this report may not Infringe priVAtely UR"•IN t ls,hlo; u1 B. Assumes any liabilities with respect to the u~e of, or for damagee resultlna' from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, "person acUng on behalf of the Commission" includes any employee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any Information pursuant to his employment or contract with the Commission, or hl-9 employment with such c~ntractor.

This rep01"1 W/l.S prepared liS an account of Government spons01"ed W01"k. Neither the United Stales, n01" the Commission, n01" any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed 01" implied, with respect to the accuracy, completeness, 01" usefulness of the information contained in this repMI, 01" that the use of any inf01"malion, apparatus, method, or process disclosed in this rep01"t may not infringe privately owned rights; 01" B. Assumes any liabilities with respect to •the use of, 01" f01" damages resulting from the use of any information, apparatus, method, 01" process disclosed in this rep01"1. As used in the above, "person acting on behalf of the Commission" includes cmy employee ur contractlW of the Commission, lW employee of such contract01", to the extent that such employee 01" contract01" of the Commission, or employee of such conlract01" prepares, disseminates, or provides access to, any information pursuant to his employmentM contract with the Commission, or bis employment with such contracl01".