RG 5.23-74 相关标准章节.docxVIP

Publication Date: 5/1/74  Pages: 16  Date Entered: 1/5/93  Title: In Situ Assay of Plutonium Residual Holdup  May 1974  U.S. ATOMIC ENERGY COMMISSION  REGULATORY GUIDE  DIRECTORATE OF REGULATORY STANDARDS  REGULATORY GUIDE 5.23  IN SITU ASSAY OF PLUTONIUM RESIDUAL HOLDUP A. INTRODUCTION  Part 70, Special Nuclear Material, of Title 10 of the Code of  Federal Regulations requires licensees authorized to possess more than  one kilogram of plutonium to calculate a material balance based on a  measured physical inventory at intervals not to exceed two months.  Further, these licensees are required to conduct their nuclear material  physical inventories in compliance with specific requirements set forth  in Part 70. Inventory procedures acceptable to the Regulatory staff are  detailed in Regulatory Guide 5.13, Conduct of Nuclear Material Physical  Inventories.  Plutonium residual holdup is defined as the plutonium inventory  component remaining in and about process equipment and handling areas  after those collection areas have been prepared for inventory. Whenever  possible, process equipment should be designed(*) and operated so as to  minimize the amount of holdup. In this guide, procedures are detailed  for the in situ assay of the residual plutonium holdup.  Assay information can be used in one of two ways: 1. When the limit of error of plutonium holdup is compatible with  constraints on the overall limit of error on the facility MUF (LEMUF),  the material balance can be computed using the measured contents of Pu  holdup. Additional cleanout and recovery for accountability will then  not be necessary.   (*) Design features to minimize holdup in process equipment are  the subject of a series of regulatory guides.  2. When the limit of error of Pu holdup is not compatible with  constraints on the overall LEMUF, the information obt