Open AccessProposal for elimination of 100 percent inspection for uranium grain size
Author(s) -
W. F. Stevenson
Publication year - 1965
Language(s) - English
Resource type - Reports
DOI - 10.2172/28390
Subject(s) - ingot , grain size , incentive , sampling (signal processing) , quality (philosophy) , statistics , process engineering , forensic engineering , reliability engineering , environmental science , engineering , materials science , mathematics , metallurgy , economics , philosophy , alloy , filter (signal processing) , epistemology , electrical engineering , microeconomics
Uranium cores have a grain size specification of A8 to A3. Large grain size is denoted by a small ``A`` number and small grain by larger ``A`` numbers. Grain sizes smaller than A9 denote an untransformed core which presumably has a high rupture potential. Grain sizes larger than A3 cause swelling, or bumping, of the fuel thus increasing the probability of rupture failure. Presently, tests are made on all cores received to determine compliance to the above specifications. As a result of a recent study and analysis of all pertinent factors applicable to this situation, it is concluded that 100% inspection of all lots received at HAPO for compliance to grain size specifications is neither warranted nor economically justifiable. In lieu of the present screening, a system is proposed to insure that screening is effected only when there is an economic incentive. Such a system requires that the Feedsite (NLO) maintain its present process control sampling plan of 5 cores per ingot. A sampling receiving inspection at HAPO will be used to detect major shifts in the quality of cores to insure that screening is used only when there is an economic incentive. This sampling inspection, in place of the present 100% screening, will result in an estimated annual savings, to IPD, of $52,500, based on the 0.0057% defective rate currently observed in the incoming material received at HAPO