NCSET Module 9

Hand Calculations - Part 2

This NCSET module has been in various stages of development for a number of years. Just before the latest version was ready for posting on the NCSP web site, a report was completed by Douglas G. Bowen and Robert D. Busch, titled — Hand Calculation Methods for Criticality Safety - A Primer — and published for unrestricted distribution by LANL. This publication covers the subject area in considerably more detail that one could expect from a typical NCSET module, and as a result release of NCSET Module 9 was determined to be redundant and would not be published.

The abstract from the report by Bowen and Busch, LA-14244-M, is reproduced below and a link to the full report on the NCSP web site follows the abstract.

The purpose of this primer is to provide an overview of the most common hand calculation methods used for criticality safety calculations. The most widely used tools available to a criticality safety practitioner are probably the common Monte Carlo or deterministic criticality safety codes, which can be used to model very complex systems. However, use of these codes can obscure the parameters that a particular fissile system may be sensitive to, whereas the hand calculation methods can be used to delve into the ways each parameter may affect the reactivity of a fissile material system. Further, practitioners must avoid using computer codes as devices that take inputs and simply provide outputs (i.e., a "black box"). Many years ago, pioneers such as Joe Thomas, David Smith, and Hugh Paxton, among others in the field of nuclear criticality safety, took the time before the advent of high-speed desktop computers to create simple hand methods for criticality safety analyses. Some of the methods can be used for single fissile units; others are applicable to fissile units arranged into simple array configurations. This primer discusses the applicability of the various methods, illustrates how they are used, and provides an interpretation of the various results. Some time investment will be needed to master the methods that could be most useful; however, they can provide the practitioner with very fast and accurate answers to criticality safety problems if they are used correctly and if critical data exist for the problem at hand. Hand calculation methods can be used as a starting point for more advanced calculations, and in many circumstances, they can provide sensitivity and perturbation information quicker than using a criticality code.

Hand Calculation Methods for Criticality Safety - A Primer by Douglas G. Bowen and Robert D. Busch.