Karen A. Miller's research while affiliated with Los Alamos National Laboratory and other places

Publications (12)

Article
The blossoming of sensing solutions based on the use of carbon materials and the pervasive exploration of compressed sensing (CS) for developing structural health monitoring applications suggest the possibility of combining these two research areas in a novel family of smart structures. Specifically, the authors propose an architecture for security...
Article
Structural Health Monitoring (SHM) technology has great unexplored potential in security applications. Specifically breakthroughs in graphene-oxide (GO) damage-detecting skins coupled with nonlinear, sparse signal processing techniques being used for SHM lend themselves to addressing the need for low-power remotely-readable tamper-evident seals. As...
Article
As new uranium enrichment plants are proposed and come online worldwide, interest in using neutron methods for uranium hexafluoride (UF6) cylinder assay has been growing; however, large discrepancies exist in published F(α,n) yields from uranium isotopes. Uncertainties in these data are propagated through the analysis of every UF6 measurement and h...
Article
The ability to detect the diversion of a significant quantity of nuclear material is the objective of international nuclear safeguards, and safeguarding uranium enrichment technology is especially important in preventing the spread of nuclear weapons. In gas centrifuge enrichment plants, the uranium is in the form of uranium hexafluoride (UF6), whi...
Article
Uranium cylinder assay plays an important role in the nuclear material accounting at gas centrifuge enrichment plants. The Passive Neutron Enrichment Meter (PNEM) was designed to determine uranium mass and enrichment in 30B and 48Y cylinders using total neutron and coincidence counting in the passive mode. 30B and 48Y cylinders are used to hold bul...
Article
Fluorine has a relatively large (α,n) production cross-section in the MeV range, the energy range of interest for special nuclear materials. In the uranium fuel cycle enriched UF6 in particular is a reasonably prolific source of (α,n) neutrons because along with 235U, 234U becomes enriched and it has a relatively short half-life. This enables the m...
Article
Safeguarding sensitive fuel cycle technology such as uranium enrichment is a critical component in preventing the spread of nuclear weapons. A useful tool for the nuclear materials accountancy of such a plant would be an instrument that measured the uranium content of UF cylinders. The Uranium Cylinder Assay System (UCAS) was designed for Japan Nuc...
Conference Paper
Current safeguards approaches used by the International Atomic Energy Agency (IAEA) at gas centrifuge enrichment plants (GCEPs) need enhancement in order to verify declared low-enriched uranium (LEU) production, detect undeclared LEU production and detect highly enriched uranium (HEU) production with adequate detection probability using non destruc...
Article
Full-text available
Current safeguards approaches used by the International Atomic Energy Agency (IAEA) at gas centrifuge enrichment plants (GCEPs) need enhancement in order to verify declared low-enriched (LEU) production, detect undeclared LEU production and detect highly enriched uranium (HEU) production with adequate detection probability using nondestructive assa...
Article
The Passive Neutron Enrichment Meter (PNEM) is a nondestructive assay (NDA) system being developed at Los Alamos National Laboratory (LANL). It was designed to determine ²³⁵U mass and enrichment of uranium hexafluoride (UFâ) in product, feed, and tails cylinders (i.e., 30B and 48Y cylinders). These cylinders are found in the nuclear fuel cycle...
Article
This paper describes an unattended mode neutron measurement that can provide the enrichment of the uranium in UF cylinders. The new passive neutron measurement provides better penetration into the uranium mass than prior gamma-ray enrichment measurement methods. The Passive Neutron Enrichment Monitor (PNEM) provides a new measurement technique that...
Article
To achieve material balance over an entire uranium enrichment plant, it is essential to verify the mass and enrichment of uranium hexafluoride (UF6) transferred in and out of the facility. A large portion of the UF6 is contained in 30B and 48Y cylinders. Traditional gamma-ray methods for UF6 cylinder assay measure the net counts in the 186-keV peak...

Citations

... The calculation results are shown in the sections below. An uncertainty in the found values Y n (E α ) was determined by comparing the calculation results with the calculated data obtained using the Nedis-2m program and with the results of high-precision direct experiments (Matsunobu et al., 1992;Lafleur et al., 2013;Miller et al., 2014;Venkataraman et al., 2019;Croft et al., 2020;Pigni et al., 2020;Broughton et al., 2021). ...
... As practical 241 AmLi sources are no longer commercially available, an alternative interrogation source must be considered as a replacement. Recent work by Menlove [11] and Miller [12] has suggested that 252 Cf is a suitable alternative to 241 AmLi in many cases, and in fact provides several benefits over the traditional option. Americium lithium is an (α,n) source, which emits single neutrons randomly in time. ...
... Previously, we reported 22 Na production cross sections based on measurements of thick-target neutron yields from the 19 F(α,n) reaction (Norman et al., 1984). Recently, there has interest in knowing the actual thick-target yields for applications such as assaying contents of UF 6 canisters using passive neutron counting techniques (Menlove et al., 2010, Smith et al., 2011). Here we report the results of our original thick-target neutron yield measurements over the energy range of E α ¼3.5–10.0 ...
... Hence, this system will have the enrichment of the feed, product and tails cylinders available without having to physically measure each cylinder. To overcome the constraints of difficult transmission measurements it was proposed to use authenticated gas pressure information similar to that from accountancy scales and load cells [11][12][13]. The systematic accuracy and statistical fluctuation of pressure-based correction for UF 6 gas density are much better than those for transmission and X-Ray Fluorescence (XRF) methods. ...
... The alpha, n neutron source would increase as the enrichment of the fuel increased, and in UF 6 it is the dominant source of neutrons because of the high alpha, n reaction rate in the fluorine. Indeed, alpha, n neutrons are the primary signature for measuring the 235 U content in UF 6 for measurement systems such as the Uranium Canister Assay System (UCAS) [11]. However, the alpha, n reaction cross section in oxygen is two orders of magnitude smaller than for fluorine, so this neutron source is very small for the LEU fuel assemblies. ...