Results of low level waste analysis of plutonium with a passive neutron coincidence counter
- Canberra Nuclear, Meriden, CT (United States). Applied Systems Div.
Measurements have been made at the Los Alamos National Laboratory (LANL) in the US and the Power Reactor Nuclear Fuel Development Corporation/Plutonium Fuel Production Facility (PNC/PFPF) in Japan with the Passive Neutron Waste Assay System (JCC-21) employing the Add-a-Source technique to quantify the plutonium content in 208 liter drums. The JCC-21 was jointly developed by Canberra Nuclear and LANL. High counting efficiency is obtained by using multiple {sup 3}He detectors in a 4{pi} geometry, and a carefully-designed high-density polyethylene moderator provides relative insensitivity to the effects of scattering reactions in the matrix. Additional high-density polyethylene also provides shielding to reduce the low-energy ambient neutron background and improves the detection limit. The Add-a-Source technique developed by LANL provides a significant improvement in accounting for matrix effects by actually measuring the matrix absorption of neutrons from a small {sup 252}Cf source and correcting the detected flux for the matrix absorption. Matrix effects and corrections using the Add-a-Source technique were evaluated during installation. A detectability limit of 0.73 mg {sup 240}Pu{sub eff} was measured for coincidence count at PNC/PFPF, making the JCC-21 one of the most sensitive and accurate NDA systems for analysis of plutonium-bearing waste. A detectability limit of 0.4 mg {sup 240}Pu{sub eff} was measured for total counts at LANL, demonstrating a lower detection limit for waste where the ({alpha},n) component is known. Enhancements to the counter design are being investigated to improve the sensitivity by reducing the background and increasing the counting efficiency. New counting techniques are also being investigated to improve the accuracy of the assay. The results of these enhancements and new techniques are presented.
- OSTI ID:
- 113112
- Report Number(s):
- CONF-930906-; ISBN 0-7918-0691-X; TRN: 95:022413
- Resource Relation:
- Conference: `93 international conference on nuclear waste management and environmental remediation, Prague (Czech Republic), 5-11 Sep 1993; Other Information: PBD: 1993; Related Information: Is Part Of Proceedings of the 1993 international conference on nuclear waste management and environmental remediation. Volume 3: Environmental remediation and environmental management issues; Baschwitz, R.; Kohout, R.; Marek, J.; Richter, P.I.; Slate, S.C. [eds.]; PB: 919 p.
- Country of Publication:
- United States
- Language:
- English
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