ML19242B826
| ML19242B826 | |
| Person / Time | |
|---|---|
| Site: | 07000025 |
| Issue date: | 06/21/1979 |
| From: | Remley M ROCKWELL INTERNATIONAL CORP. |
| To: | Partlow J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| NUDOCS 7908090442 | |
| Download: ML19242B826 (2) | |
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Energy Systems Group k
8900 Ce soto Avenue Canoga Park. CA 91304 Teleonone: 1213) 341-1000 Rockwell TWX; 910-4941237 lnternat10nal Tetex: 181017 s
June 21, 1979 In reply refer to 79ESG-6218 EE(EE_'.[
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Mr. James G. Partlow, Chief Material Centrol Licensing Branch
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Division of Safeguards D
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Dear Mr. Partlow:
This is to inform you of an impending R&D effort at the Energy Systems Group to be conducted in the Rockwell International Hot Lab (RIHL). The activities will involve the development and checkout of a process for removal of zir. onium cladding and a possible uranium-zirconium inter-metallic cor~,und (UZr2) from uranium-molybdenum alloy fuel rods from the Fermi re1ctor.
This work will be done as an R&D effort as authorized under our Special /
Nuclear Material License, No. SNM-21, and requires no license amendments or modifications. Consequently, this letter is to present a description of the proposed development process for your information.
Dissolutier, recovery of this fuel is planned by E. I. Du Pont, Savannah River plant.
However, uraniw and zirconium are known to react at high temperature
'.o form UZr2 This compcund is known to result frecuently in an uncontr711ed reaction in the presence of HNO, the normal dissolver 3
acid used at the Savannah River plan:.
Energy Systems Group has contracted with DOE-Savanuh River to declad the fuel and to remove the UZrg to enable Du Pont to recover the material. To acccmplish this, a single element is being shipped for the performance of decladding tests.
Three test processes have been devised and will be evaluated for feasibility.
These processes are hydriding, centerless grinding, and oxidation.
To accomplish these tests, one Fermi fuel assembly will be transferred into Cell 4 of the RIHL and disasserbled. The assembly consists of 140 fuel pins as U-10% Mo, enriched to 25.35 in U-235.
A total of 4673 grams of U-235 is contained in the assemblj. Thus, each pin contains 33.4 grams of U-235, together with a negligible amcunt of Pu.
Of the 140 pins, 10 will be transferred into Cell 1 for testi g,10 will go into Cell 2 for possible use in the test plan, and tre remainder will either be recanned and transferred back to the RMDF for storage or held in the hot cell until completion of all tests, when it will be returned with the test material. Thus, only 668 grams cf J-235 is planned to be used in the test program.
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79ESG-6218 June 21, 1979 Page 2 The 10 pins in Cell 1 will be weighed and cut into 3 to 5 sections, depending on the test process, and each sectior will be uniquely numbered to retain traceability. Each of these sections will be weighed, dimen-sionally measured, and all data recorded on a data sheet.
For the hydriding test plan, sections of pins will be loaded into a boat and put in a furnace at a temperature of 6000 to 950 C in a H2 atmosphere, and hydrided and cooled at different time frames and temperatures to determine minimum conditions for spalling to occur.
If spalling occurs, the spalled material will be gathered and measured for U content; the intact fuel pins will be weighed and dimensioned and data recorded. The pins will then be examined for the presence of UZr2 If spalling does not occur, ti;e section will be measured as in the previous paragraph and then beat with a hammer until the hydride and possibly the fuel is broken.
In both cases, the removed material will be sampled and analyzed for U content.
If these tests fail to produce adequate separation of the U and UZr2, this approach will be abandoned and centerless grinding will be tested.
For the centerless grinding test plan, nine pin s'ections (three pins) will be ground on settings for three feeds and three speeds, and dimen-sional measurements will be made and recorded on a data sheet. These steps will continue until the pin diameters have been reduced by at least 0.020 in. After evaluation of these tests and data, two full-length pins will be ground using the most effective of the three feeds and three speeds until their diameters have been reduced by 0.020 in. or until all evidence of Zr and UZr2 is removed, whichever occurs last. At this point, the zirconium end caps will be cut off. This material and grindings will be sampled and analyzed for uranium content.
The results of these tests will be evaluated conjointly with those from hydriding, and the process and parameters that have the best yield in terms of cost, material accountability, and ease of disposal will be adopted.
If neither hydriding nor grinding is successful, the uranium will be oxidized to a fine powder.
To aid in oxidation of the uranium, the pins will be cut into short lengths of approximately 1 in, long.
These pieces will be loaded into a furnace and heated while wet air flows slowly through the furnace. The zirconium may also oxidize to a powder, or it may remain a hollow cylinder. After the furnace ccols, the pcwder and any large pieces will be collected into separate piles and each will be sampled and analyzed for U.
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79ESG-6218 June 21, 1979 Page 3 Based on the results of this test, parameters will be changed in a series of runs to optimize the process in terms of processing time, completeness of the oxidation reaction, and degree of U-Zr separation.
To determine tha level of separation achieved in the various processes, the uranium contents of the products must be measured.
Because the actual activity of the fuel is unknown, the type of measurement used will be determined following each process.
All data on the processes undertaken will be recorded on process data sheets and laboratory notebooks. At the conclusion of these development efforts, all data will be collected and a final report and material balance will be issued.
If you have any questions or need further information, please call me.
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. Remley, Direc Health, Safety & Radiation Services Energy Systems Group cef:4/10-12 13202
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