The Manhattan Project Resources

U.S. Department of Energy

HSS Office of Classification

Office of History and Heritage Resources

Plutonium: The First 50 Years

APPENDIX A: EXCESS WEAPON GRADE PLUTONIUM

Over the years, DOE has produced, acquired and maintained large inventories of plutonium for nuclear weapons production and non-defense related missions. With the end of the Cold War and resulting diminished strategic military threat, opportunities presented themselves for the Department to redirect its priorities from weapons production activities to other critical national security missions. With the reduction in nuclear weapons, significant quantities of weapons grade plutonium became excess to national defense needs.

On September 27, 1993, the President issued a Nonproliferation and Export Control Policy which set forth the framework for U.S. efforts to prevent the proliferation of weapons of mass destruction. As a key element of the President's policy, the U.S. committed to eliminating, where possible, the accumulation of stockpiles of highly enriched uranium and plutonium and to ensure that where these materials already exist, they are subject to the highest standards of safety, security, and international accountability.

In support of this policy, the Departments of Energy and Defense performed an in-depth review of the fissile material required to support the nuclear weapons program and other national security needs. This was compared to available materials and as a result, 38 MT of weapon grade plutonium were declared excess to national defense needs (Table 15).

In keeping with the President's policy, the Secretary of Energy announced on December 20, 1994, that plutonium and weapons usable highly enriched uranium that was separated and/or stabilized during the phase out, shutdown, and cleanout of weapons complex facilities would be set-aside as restricted use material and not used for nuclear explosive purposes.

On March 1, 1995, in a speech at the Nixon Center for Peace and Freedom, President Clinton stated, "To further demonstrate our commitment to the goals of the Treaty [note 27], today I have ordered that 200 tons of fissile material -- enough for thousands of nuclear weapons -- be permanently withdrawn from the United States nuclear stockpile. It will never again be used to build a nuclear weapon."

APPENDIX B: PLUTONIUM WASTE

The report, Plutonium: The First Fifty Years, focuses on the U.S. Government production, acquisition, and utilization of plutonium during the past fifty years and the Nuclear Materials Management and Safeguards System (NMMSS) which is used to track and account for this plutonium. Information in the NMMSS has changed over the years reflecting improved measurement technologies and increased accounting requirements. This appendix addresses the plutonium in waste that the Department manages. Plutonium in waste is not included in the DOE/DoD 99.5 MT plutonium inventory as presented earlier in this report. In addition, this appendix explains the differences between quantities of plutonium in "normal operating losses" and the "waste" accounts within the NMMSS. It also presents how data from the NMMSS compare to other Departmental materials inventory systems that track plutonium in waste.

Normal Operating Losses Compared with Plutonium in Waste in NMMSS.

Section 10.3 of this report identifies the amount of plutonium in a NMMSS category referred to as "normal operating losses" (NOL). Plutonium that is technically or economically unrecoverable and intentionally sent to waste is referred to as NOL and removed from the DOE/DoD plutonium inventory. The DOE/DoD plutonium inventory requires strict safeguards and security. The plutonium in waste is not subject to the same degree of rigorous safeguards and security as the DOE/DoD plutonium inventory.

  • The quantities of plutonium removed from the DOE/DoD inventory and placed in waste as NOL are determined by either direct measurements or estimated based on measured sampling methods and practices -- for example, all liquid wastes are sampled and analyzed prior to being sent to a waste tank. The NMMSS indicates that a total of 3.4 MT of plutonium was sent to waste by way of NOL.
  • The method used in estimating plutonium in waste burial sites and tanks was based on extrapolation from direct measurements of the waste -- for example, a small sample of radioactive waste is taken from a waste tank, the amount of plutonium in that sample is analyzed, and the amount of plutonium is estimated by multiplying this small sample times its relative proportion in the larger waste volume. The total amount of plutonium in NMMSS waste accounts is 3.9 MT (see Figure 14 and Table 16).

Because the NMMSS was originally designed for nuclear materials safeguards purposes, there was no need to reconcile the NOL quantities with the later quantities recorded in the NMMSS waste accounts for materials management purposes. The 0.5 MT difference in NMMSS between the NOL estimate of 3.4 MT and the 3.9 MT "waste" estimate is attributable to two primary causes:

  1. Waste inventories are tracked for environmental, safety and health reasons, and are therefore not necessarily calculated like normal operating losses. Waste inventory calculations and normal operating losses both rely on independent measured estimates, which lead to some degree of uncertainty in each. The normal operating losses are used for safeguards and security purposes and may not include all the information that may be required for waste inventory.

    In the early 1970s, sites began reporting details of plutonium in waste for the first time to NMMSS. At most sites the estimates of the amount of plutonium in waste were based on direct measurements of waste and provided confirmation of the NOL estimates of waste. In the case of Hanford, however, the 1974 estimate indicated 0.4 MT more plutonium in waste than in normal operating losses. This difference could be either: an accounting error at the site, such as reporting plutonium already included in the normal operating losses; or additional plutonium not captured by the normal operating losses tracking system, and therefore likely reported as "inventory differences [note 28]." While site records do not allow the Department to determine the source of this inconsistency at this time, the Department has performed additional analysis supporting the higher estimate of plutonium in waste and, using this higher estimate, has determined that there are no imminent health, safety, or environmental risks. Since 1974, the annual normal operating losses and waste inventories have tracked very closely.

  2. Waste includes offsite sources, including plutonium waste from the Navy and from licensed commercial facilities. Most commercial waste came from two facilities that fabricated fuel for reactors: the Nuclear Fuel Services at Erwin, Tennessee, and Cimarron Corporation at Cresent, Oklahoma. Normal operating losses include only waste generated from government onsite production. Since 1974, the remaining 0.1 MT inconsistency tracks closely to wastes received from sources outside of the Department.

Waste Quantities in the NMMSS Compared to Other Departmental Waste Material Databases.

In addition to the difference between waste and normal operating losses within NMMSS, the amount of plutonium waste in this report may not agree with the amount of plutonium in waste reported in other Departmental sources, such as the Integrated Database (IDB) or sitespecific waste tracking systems. Two primary reasons for these apparent inconsistencies include: (1) the NMMSS waste data reflect only fissile plutonium inventories (i.e., Pu239), while other sources include all isotopes of plutonium; and (2) the IDB does not differentiate between waste that requires nuclear materials safeguards, and therefore is still recorded as part of the inventory, and waste that has actually been removed from the inventory and physically sent to a waste burial site. Because of different intended uses of these databases, differing quantities of plutonium in waste can arise.

The Department has formed a working group to analyze NMMSS, IDB, and other Departmental tracking systems and to make recommendations on the appropriateness of integrating the various inventory systems or developing a new tracking system for all forms of plutonium.

For more information on the environmental, safety and health problems related to waste across Departmental sites and what the Department is doing to address those problems, please refer to the DOE Office of Environmental Management report, Closing the Circle on the Splitting of theAtom, January 1995.



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