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NRC proposes changes to its rules on nuclear materials
In response to Executive Order 14300, “Ordering the Reform of the Nuclear Regulatory Commission,” the NRC is proposing sweeping changes to its rules governing the use of nuclear materials that are widely used in industry, medicine, and research. The changes would amend NRC regulations for the licensing of nuclear byproduct material, some source material, and some special nuclear material.
As published in the May 18 Federal Register, the NRC is seeking public comment on this proposed rule and draft interim guidance until July 2.
L. R. Bunney, D. Sam
Nuclear Science and Engineering | Volume 39 | Number 1 | January 1970 | Pages 81-91
Technical Paper | doi.org/10.13182/NSE70-A21173
Articles are hosted by Taylor and Francis Online.
Experimental measurements of the gamma-ray spectra emitted by the products of thermal-neutron fission of 235U have been made at nine selected times (¼, ½, 1, 2, 5, 10, 24, 48, and 72 h) after fission. A calibrated and highly collimated 5- × 5-in. NaI(T1) detector was used. The 100-energy-bin γ-ray spectra were unfolded from the pulse-height distributions by means of an iterative method. Extensive use was made of machine computation. The number of fissions in each sample was determined radiochemically. Significant differences between this work and calculated spectra were found. At the earlier times the experimental photon emission rate is higher than the calculated rate by as much as 40%. At later times the experimental rate is 20% lower than the calculated rate. Surprisingly large differences (as much as 33%) were found between the photon emission rates of products of fission by slow neutrons and by fast neutrons.
