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Title: The Scientific Challenges in Stewarding the U.S. Nuclear Weapons Stockpile

Abstract

No abstract provided.

Authors:
 [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1343730
Report Number(s):
LA-UR-17-21138
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION

Citation Formats

Wilburn, Wesley Scott. The Scientific Challenges in Stewarding the U.S. Nuclear Weapons Stockpile. United States: N. p., 2017. Web. doi:10.2172/1343730.
Wilburn, Wesley Scott. The Scientific Challenges in Stewarding the U.S. Nuclear Weapons Stockpile. United States. doi:10.2172/1343730.
Wilburn, Wesley Scott. 2017. "The Scientific Challenges in Stewarding the U.S. Nuclear Weapons Stockpile". United States. doi:10.2172/1343730. https://www.osti.gov/servlets/purl/1343730.
@article{osti_1343730,
title = {The Scientific Challenges in Stewarding the U.S. Nuclear Weapons Stockpile},
author = {Wilburn, Wesley Scott},
abstractNote = {No abstract provided.},
doi = {10.2172/1343730},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 2
}

Technical Report:

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  • Ceramic materials are used extensively in non-nuclear components in the weapons stockpile including neutron tubes, firing sets, radar, strong link and weak link assemblies, batteries, and current/voltage stacks. Ceramics also perform critical functions in electronics, passively as insulators and actively as resistors and capacitors. Glass and ceramic seals also provide hermetic electrical feedthroughs in connectors for many weapons components. The primary goal of the ceramic material lifetime prediction program is to provide the enhanced surveillance program with the capability to specify the reliability and lifetimes of glass and ceramic-containing components under conditions typical of the stockpile environment. The authors havemore » studied the reliability and subcritical crack growth (SCG) behavior of 94% alumina (Al{sub 2}O{sub 3}), which is likely the most common ceramic in the stockpile. Measurements have been made on aluminas manufactured by four war reserve qualified vendors (Coors, Wesgo, AlSiMag, and Diamonite). These materials are expected to be representative of typical product obtained from vendors who have supplied alumina for weapons components during the past several decades.« less
  • Lawrence Livermore and Los Alamos National Laboratories have developed a common framework and key elements of a national certification methodology called Quantification of Margins and Uncertainties (QMU). A spectrum from senior managers to weapons designers has been engaged in this activity at the two laboratories for on the order of a year to codify this methodology in an overarching and integrated paper. Following is the certification paper that has evolved. In the process of writing this paper, an important outcome has been the realization that a joint Livermore/Los Alamos workshop on QMU, focusing on clearly identifying and quantifying differences betweenmore » approaches between the two labs plus developing an even stronger technical foundation on methodology, will be valuable. Later in FY03, such a joint laboratory workshop will be held. One of the outcomes of this workshop will be a new version of this certification paper. A comprehensive approach to certification must include specification of problem scope, development of system baseline models, formulation of standards of performance assessment, and effective procedures for peer review and documentation. This document concentrates on the assessment and peer review aspects of the problem. In addressing these points, a central role is played by a 'watch list' for weapons derived from credible failure modes and performance gate analyses. The watch list must reflect our best assessment of factors that are critical to weapons performance. High fidelity experiments and calculations as well as full exploitation of archival test data are essential to this process. Peer review, advisory groups and red teams play an important role in confirming the validity of the watch list. The framework for certification developed by the Laboratories has many basic features in common, but some significant differences in the detailed technical implementation of the overall methodology remain. Joint certification workshops held in June and December of 2001 and continued in 2002 have proven useful in developing the methodology, and future workshops should prove useful in further refining this framework. Each laboratory developed an approach to certification with some differences in detailed implementation. The general methodology introduces specific quantitative indicators for assessing confidence in our nuclear weapon stockpile. The quantitative indicators are based upon performance margins for key operating characteristics and components of the system, and these are compared to uncertainties in these factors. These criteria can be summarized in a quantitative metric (for each such characteristic) expressed as: (i.e., confidence in warhead performance depends upon CR significantly exceeding unity for all these characteristics). These Confidence Ratios are proposed as a basis for guiding technical and programmatic decisions on stockpile actions. This methodology already has been deployed in certifying weapons undergoing current life extension programs or component remanufacture. The overall approach is an adaptation of standard engineering practice and lends itself to rigorous, quantitative, and explicit criteria for judging the robustness of weapon system and component performance at a detailed level. There are, of course, a number of approaches for assessing these Confidence Ratios. The general certification methodology was publicly presented for the first time to a meeting of Strategic Command SAG in January 2002 and met with general approval. At that meeting, the Laboratories committed to further refine and develop the methodology through the implementation process. This paper reflects the refinement and additional development to date. There will be even further refinement at a joint laboratory workshop later in FY03. A common certification methodology enables us to engage in peer reviews and evaluate nuclear weapon systems on the basis of explicit and objective metrics. The clarity provided by such metrics enables each laboratory and our common customers to understand the meaning and logic of technical and management decisions affecting stockpile performance and safety.« less
  • We review here results of several classes of US nuclear weapons tests conducted withith the principal strengths and weaknesses of nuclear weapons themselves. It is found that a high degree of confidence in the reliability of the existing stockpile is justified, and that it is sufficiently robust to permit confidence in the reliability of remanufactured warheads in the absence of nuclear explosive proof-tests. We also review problems encountered with the 14 nuclear weapon designs since 1958 that have been frequently and prominently cited as evidence that a Low-Threshold Test Ban (LTTB) or a Comprehensive Test Ban (CTB) would preclude themore » possibility of maintaining a reliable stockpile. It is concluded that that experience has little if any relevance to the question of maintaining the reliability of the stockpile of nuclear weapons that exists in 1987. Further, we discuss actions necessary to assure the future availability of materials needed to remanufacture nuclear weapons in the existing stockpile and the reliability of repackaged nuclear weapons. It is recommended that the Department of Energy be encouraged to undertake the formulation and execution of a Readiness Program whose purpose is to ensure that the US is prepared to maintain the reliability of its stockpile of nuclear weapons in the absence of nuclear explosive tests, and that funds earmarked for this purpose be provided.« less
  • The focus of this grant, entitled ''Experimental investigations of magnetic, superconducting, and other phase transitions in novel f-electron materials at ultra-high pressures using designer diamond anvils'', is to explore the novel properties of f-electron compounds under pressure, with a particular emphasis on the physics of superconductivity, magnetism, and their interactions. This report is a synopsis of the research that was undertaken from 6/2006-6/2007.
  • The focus of this grant, entitled 'Experimental investigations of magnetic, superconducting, and other phase transitions in novel f-electron materials at ultra-high pressures using designer diamond anvils', is to explore the novel properties of f-electron compounds under pressure, with a particular emphasis on the physics of superconductivity, magnetism, and their interactions. This report is a synopsis of the research that was undertaken from 6/2007-6/2008.