Question 1: What went wrong at NFS?
Several problems were identified in the NFS accounting and record-keeping system. In one facility there was an apparent shortage of uranium. In a connecting plant there was an apparent excess. The sum of the two discrepancies was a plus. The differences between "book" inventory and actual material on hand was discovered in a routine physical inventory. NRC was notified and the plant was shut down for reinventory in order to determine what happened. NRC appointed a special task group to visit the plant to determine what led to the accounting discrepancies. The task group reported that the discrepancies were caused in part by a bias in the measurement of dissolver solution in the licensee's scrap recovery plant and in part by the licensee's overstatement of the quantity of uranium contained in liquid discards. The measurement bias occurred when undissolved scrap residue was transferred to the accountability weigh tank. This caused a pipe blockage in the tank, improper mixing of the weigh tank solution, and the removal and analysis of accountability samples which were not representative of the concentration of uranium actually present. The overstatement of uranium in liquid discards resulted from the licensee's practice of recording "less than" measurement determinations as quantities of uranium actually discarded. As an example, if the licensee determined that the amount of uranium in the discarded material was less than 0.005 grams per liter, the quantity of the recorded discard would be based on the maximum value (i.e. 0.005 grams per liter). The recorded amount would be greater than the amount of material actually discarded.
Corrective actions have been implemented by NFS. Improved methods are now employed to assure against the transfer of undissolved residues to the accountability weigh tank and to continually check to assure against another pipe blockage. Also, NFS is making more sensitive measurements of liquid discards and is now recording only the quantities of uranium actually present. In addition to needed improvements in the accountability system, the task group identified other areas in the safeguards program where prompt upgrading was necessary. One of the needed improvements related to the company's practice of relying on the honor system to check for concealed special nuclear material on individuals departing from material access areas. The company was directed to
cease this practice and to employ a watchman continuously at each authorized exit and entry point to assure that searching is properly carried out. Needed upgrading has been accomplished.
Question 2: What assurance is there, in the presence of this apparently unreliable accounting system, that materials have not been illicitly removed from the plant?
The NRC task group investigation did not find any information that would indicate that special nuclear materials have been illicitly removed from the plant.
Question 3: Does this incident carry any implication regarding the overall usefulness of material control and accounting systems?
Yes, these systems needed to be improved. The inventory anomalies at NFS also evidence that we cannot depend exclusively on accounting systems to control nuclear material. This is the reason that the NRC is placing increased emphasis on physical security and overall aspects of material control. Such measures include personnel access control and containment procedures such as tamper proofing of sensitive vaults, exit searches and portal sensors. The investigation at the Erwin plant identified several areas where prompt improvements should be accomplished, and these improvements have been made.
Question 4: What accuracy can be expected from material control and accounting systems in large reprocessing and fabrication plants which would be associated with large scale plutonium recycle?
Under NRC regulations, accuracy of an operator's accounting system must be reliable down to 0.5% of throughput quantities for fuel production operations. For reprocessing plants, the control limit is 1% for plutonium and 0.7% for uranium. While improvements can be made in the future and will be required (including a more timely accounting system), sole reliance would not be placed on bookkeeping to detect diversion. Accordingly, as noted above, NRC would insist that an in-depth security system be utilized to monitor, prevent, detect, or defeat any attempt to illicitly remove nuclear materials from licensed plants. NRC also believes that "engineered redundancy" which is used so successfully in design of reactors for safety purposes, can also be effectively employed to protect against any such unauthorized diversion of materials.
JAMES A. HALEY, FLA, CHAIRMAN
OTA. TAYLOR, N.C.
AROLD T. JOHNSON, CALIF.
GDALL, AREZ
PHILLIP BURTON, CALIF.
ROBERT W. KASTIDIMETER, WIS. PATSY T. MINK, HAWAII LLOYD MEEEDS, WARM. ABRAHAM KAZEN, JR., TEX. BOBET G. STEPNENS, JR., GA. XSEPH P. VIGORITO, PA. JOHN MELCHER, MONT.
RONICALIS, WYO. JONATHAN B. BINGHAM, NY. JOHN P. SEXMERLING, CHIQ BOLD HUNNELS, N. MEX. ANTOMUS MORIA WON PAT, QUAM NON DE LUB0, V.J.
108 ECKHARDT, TEX
SOODLOE E. STRON, MD,
INNE BENITEZ PR.
IM SANTING, NEY.
FRUA & TRANSAS, MASS.
ALLAN T. HOWE, UTAH
JAMES WEAVER, ORES.
BOB CARR, MICH.
GEORGE MILLER, CALIF.
THEODORE M. (TED) REBENDOVER,
JOE SKUBITZ, KANS. SAM STEGER, ARIZ. DON M. CLAUSEN, CALIF. PHILIP E. RUPPE, MICH. MANUEL LUJAN, JR. N. MEX. KEITH G. SEBELAS, KANS. ALAN STEELMAN, TEX. DON YOUNG, ALASKA ROSENT E. BAUMAN, MD. STEVEN D. SYMMS, IDAHO JAMES P. (JIM) JOHNSON, COLO. ROBERT J. LAGOMARBING, CALIF. VIRGINGA SMITH, HER. SHIRLEY N. PETTIS, CALIF.
COMMITTEE ON INTERIOR AND INSULAR AFFAIRS
U.S. HOUSE OF REPRESENTATIVES WASHINGTON, D.C. 20515
Chairman, Nuclear Regulatory Commission
1717 M Street, N.W.
Washington, D.C.
LEE MC ELVAIN
GENERAL COUNSEL
MICHAEL C. MARDEN MINORITY COUNSEL
The January 14 Washington Post carried an article by Thomas O'Toole concerning export of research reactor and HTGR fuel. The article suggests there might be significant advantages from the safeguards standpoint if we restricted exports of such fuels to uranium not enriched to the point where it could be used in a nuclear explosive. I would appreciate your views on the feasibility of such restrictions. Since it comes as something of a surprise that such materials have been exported to the extent implied in the article, I would also be grateful if you would indicate the annual quantities which have been exported over the past decade, the size of each shipment involving more than five kilograms, where the material has gone, what it is used for, and to what extent the NRC keeps track of it once it has left the United States.
The Subcommittee on Energy and the Environment is considering holding hearings concerning what might be done to increase the difficulty of fabricating nuclear explosives. I would therefore also welcome your views on the practicality of various schemes proposed for blending plutonium and uranium oxides.
Morris K. Udall
Chairman, Subcommittee on Energy and the Environment
Honorable Morris K. Udall
Chairman, Subcommittee on
Energy and the Environment
Committee on Interior and Insular Affairs U. S. House of Representatives
I am pleased to respond to your letter of January 16, 1976, concerning the export of research reactor and HTGR fuel and related questions. You requested the views of the Nuclear Regulatory Commission on the feasibility of restricting the export of such fuels to uranium not enriched to the point where it could be used in a nuclear explosive, and our views on the practicality of increasing the difficulty of fabricating nuclear explosives through the blending of plutonium and uranium oxides. Answers to these questions have been prepared by the NRC staff and will be found in Enclosure 1.
You also requested shipment and end-use information concerning the supply of highly enriched material abroad during the past decade. As was discussed with Henry Myers of your staff, we are faced with some practical problems in retrieving all of this information. Enclosed are two tables covering 1969 through 1975, one showing total exports by year and one showing exports of significant quantities of material by country of destination. End-use information is included only for 1974 and 1975. We will provide to you the additional shipment and end-use information as soon as we can.
I am hopeful that you will find this information useful and we hope to provide the additional information soon. Please let us know if we may be of further assistance.
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