Development of an analytical theory to describe the PNAR and CIPN nondestructive assay techniques

Cadmium Subtraction Method for the Active Albedo Neutron Interrogation of Uranium

“…Recently, Bolind [9] has developed an analytical theory of the PNAR-FC and 252 Cf Interrogation with Prompt Neutron Detection methods for underwater spent nuclear fuel (SNF) characterization in order to explain why they are closely allied approaches, in the sense that they both provide a measure of reactivity. They also share some key underlying dependence on the BIC parameters (burnup, initial enrichment, and cooling time), which provide a crude means to describe the isotopic composition of spent low-enriched uranium (LEU) pressurized water reactor (PWR) fuel assemblies.…”

“…Furthermore, the approach does not consider PNAR-3 He based on coincidence counting because additionally PNAR-3 He requires the time domain to be understood [4]. In that regard, the approach of Bolind [9] does not consider the doubles neutron counting rate signature and only considers the singles rate signature (time-averaged neutron balance).…”

Passive neutron albedo reactivity measurements of spent nuclear fuel

“…The ratio of the measured neutron flux in the two configurations, high multiplication divided by low multiplication, is called the PNAR Ratio and is a measure of the multiplication in the fuel assembly for which the fissile content creates the chain reaction. The PNAR concept was originally proposed in 1982 by Lee and Lindquist [6] and the method has recently been discussed in more detail in several publications [7][8][9][10].…”