Nuclear archaeology to assess fissile-material inventories for nuclear safety and security, transparency, and disarmament

Figures & data

Figure A1. Two-dimensional implementation in SERPENT 2 of Savannah River Site’s K Reactor’s inner core with the Mark 15 fuel design (left). Detail of the fuel element (right).

Figure A2. Illustration (in the form of vials) of mixing the waste from two different plutonium-production campaigns “A” and “B” in one waste tank. “Cooling time” refers to the age. Courtesy of Antonio Figueroa.

Table A1. Implemented priors used to reconstruct the plutonium-production history (whose true parameter values are also shown here) using Bayes’ theorem

	True value	Implementation without prior information	Implementation with prior information on the declared campaign
Burnup (declared campaign)	1.8 MWd/kg	0-3 MWd/kg	1.7–1.9 MWd/kg
Age (declared campaign)	10 years	0–50 years	9–11 years
Burnup (undeclared campaign)	0.8 MWd/kg	0–3 MWd/kg	0–3 MWd/kg
Age (undeclared campaign)	30 years	0–50 years	0–50 years

Figure A3. Posterior distributions for the declared campaign (“a”) and the undeclared campaign (“b”), as well as the mass ratio $\alpha$. Courtesy of Antonio Figueroa.

Table A2. Posterior uncertainties on the undeclared campaign

	Burnup uncertainty (standard deviation) of the undeclared campaign (%)	Age uncertainty (standard deviation) of the undeclared campaign (%)
No prior information	30	24
Prior information only on the declared campaign	17	17