Transmuting Long Lived Nuclear Waste Into Valuable Materials ( R Schenter & M Korenko)

Transmuting Very Long Lived Nuclear Waste Into Valuable Materials Robert E. Schenter and Michael K. Korenko Advanced Medical Isotope Corporation and Curtiss-Wright Corporation November 13,2008

Bottom Lines 1. Hundreds of calculations were made which show that large quantities (kgs) of Tc-99 and I-129 can be burned out in a single target subassembly in a large fast reactor.

2. Also large quantities and activities of the “beneficial isotopes� Ru-100 and I-131 can be produced using the same target design 3. These calculations were performed using the computer codes MCNPX and CHAIN

Introduction-1 1. Disposal and storage of very long lived fission products (Tc-99 th=4,200,000years I-129 th=15,700,000years,et al.) in a facility such as Yucca Mountain is a very expensive and fairly unreliable process.

In this paper we present results of physics analyses that we feel represents a much better solution.

2. A number of analyses have been made in the past on transmuting long lived fission products using fission reactor and accelerator systems.

However, none have looked into producing valuable materials.

3. Fast reactors are very effective in being able to “flux tailor” the neutron spectrum. This was done extensively during the 1980’s and early 1990’s in the FFTF.

Introduction-2 4. I-131is a very important medical isotope used in the treatment of thyroid cancer non-Hodgkins Lymphoma, et al. Along with Mo-99, I-131 is in short supply. They are both obtained from Canada, Europe and South Africa.

Currently the reactors that produce these isotopes are shut down or not being replaced. There is no US Production of Mo-99 or I-131.

5. The total production of Tc-99 and I-129 in a 1000 Megawatt Thermal Reactor is: Mass Tc-99/year= 9.88kg Mass I-129/year= 1.14kg

“Yucca Mountain Cost estimate tops $90 billion”

Las Vegas Review - Journal July 16, 2008 “Washington --The projected costs to build a nuclear waste repository at Yucca Mountain, ship used radioactive fuel to Nevada from around the country and operate the site for 100 years have grown to more than $90 billion, an energy department official said Tuesday”

Calculations 1. Calculations were made for a number of target designs and materials using the MCNPX computer code.

A single target assembly was modeled (cylindrical geometry) with dimensions similar to the FFTF “Hex� assemblies. Pins and Homogeneous(target isotope and moderating material homogeneously mixed together).

Given the MCNPX results (cross sections versus target mass and perturbed fluxes) CHAIN cod calculations were made which include time dependent self-shielding factors. These calculations were made for several different irradiation times.

2.

3. Results from these calculations are presented next.

Self Shielding Effects MCNPX Calculates FF for a given target mass m(t)

CHAIN Code Time dependent cross sections FF= 1.0/Sqrt( 1.0+C*m**B) Sigma(m(t))=FF*Sigma(m=0.0)

Technitium-99 Burnout 8 Pin Model 7/13/08 1.00E+04 9.00E+03 8.00E+03

Mass(grams)

7.00E+03 6.00E+03 5.00E+03 4.00E+03 3.00E+03 2.00E+03 1.00E+03 0.00E+00 0

50

100

150

200

Irradiation Time(days)

250

300

350

400

Previous Experimental Data 1.

Burnout results were obtained from the FFTF Multi-Isotope Production Test(May1989). The test results showed good agreement of “burnout” for the Tc-99 and I-129 targets resulting in C/E values of 0.8 and 0.86, respectively.

These results help confirm the capture cross sections we have been using.

2. Thermal cross sections, resonance integrals and resonance parameters have been well measured.* Tc-99: sigmat=22.8b Ires=368b I-129: sigmat=30.3b Ires=33.8b *See for example S.F. Mughabghab “Atlas of Neutron Resonances” 2006

Conclusion Breakthrough Design/Calculations • In one year a single fast reactor tailored spectrum assembly can transmute – A year’s worth of the longest life isotopes technetium 99 or iodine 129 from a thermal reactor

Technetium 99 Burnout 100 90 80 70 60 50 40 30 20 10 0 0

50

100

150

200

Irradiat ion Time( days)

250

300

350

400