Publication Date: 12/1/72     Pages: 1     Date Entered: 2/22/84     Title: SERIAL NUMBERING OF FUEL ASSEMBLIES FOR LIGHT-WATER-COOLED NUCLEAR POWER REACTORS     12/20/72     U.S. ATOMIC ENERGY COMMISSION     REGULATORY GUIDE     DIRECTORATE OF REGULATORY STANDARDS     REGULATORY GUIDE 5.1     SERIAL NUMBERING OF FUEL ASSEMBLIES FOR LIGHT-WATER-COOLED     NUCLEAR POWER REACTORS A. INTRODUCTION     Part 70 of the Atomic Energy Commission's regulations requires     that certain licensees establish and maintain written material control     and accounting procedures which are sufficient to enable the licensee to     account for the special nuclear material (SNM) in his possession. In     the case of SNM contained in fuel assemblies, a system of control based     on unique item identification of each fuel assembly is desirable to     achieve an acceptable level of accountability control. This guide     describes an acceptable numbering method for item identification of fuel     assemblies for light-water-cooled nuclear power reactors. B. DISCUSSION     Power reactor fuel is relatively inaccessible while at a reactor     facility. The SNM itself is securely contained within the fuel     cladding. Accurate quantitative measurements of the SNM content of the     fuel assemblies are exceedingly difficult, and as yet not feasible     except through use of techniques requiring disassembly into individual     fuel rods. The SNM content of a fuel assembly is currently obtained by     determining the SNM content in each discrete item (element or rod), and     then verifying the presence of such items. The principal diversion     threat for SNM at the reactor consists of theft of identifiable items.     Accordingly, the AEC's material protection inspection practices for SNM     contained in completed fuel assemblies on inventory at light-water     reactor facilities are based on assuring that all individually     identifiable fuel pieces received at the facility are still on hand or     have been shipped to other licensed facilities.     A substantial level of assurance can be provided within this     context if each fuel assembly is uniquely identified by a number     inscribed in its structure. The unique numbering also offers an     advantage at the time of reprocessing in that fuel assemblies can be     readily identified according to origin and irradiation history, thus     avoiding confusion in formation of dissolver batches.     The Fuel Assembly Identification Working Group of Subcommittee     ANS-13, Fuel Assembly Criteria, has developed a standard (ANS 13.8) for     fuel assembly identification. This standard was approved by the     American National Standards Institute as N18.3-1972(1) on May 10, 1972.     Some fabricators purposely manufacture fuel assemblies that can be     dismantled without any metal-cutting operation. This design feature     allows relatively easy substitution of fuel rods, but complicates the     verification of discrete power reactor fuel items. C. REGULATORY POSITION 1. The provisions contained in ANSI N18.3-1972, "Fuel Assembly     Identification," are generally acceptable and provide an adequate     numbering basis for identification of individual fuel assemblies from     the time of final fuel rod consolidation at the fabricator's facility     until the assembly is dissolved as an entity. 2. In the special case of fuel assemblies from which a fuel rod or     other SNM-containing component may be removed without the need of a     metal-cutting operation, further identification and accounting measures     in addition to those required in ANSI N18.3-1972 may be necessary. This     determination will be made on an individual case basis.     ----------     (1) Copies may be obtained from the American National Standards     Institute, Inc., 1430 Broadway, New York, New York 10018.     ----------     40