Hanford tank residual waste – Contaminant source terms and release models

Deutsch, William J.; Cantrell, Kirk J.; Krupka, Kenneth M.; Lindberg, Michael L.; Serne, R.J.

doi:10.1016/j.apgeochem.2011.04.025

Cited by 22 publications

(26 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This correction was applied to the ICP results of the glasses to account for the Re in the original feed. The retention ratio (R i ) [25] of the i-th constituent of a heat-treated sample was calculated with the formula (1) where g i,r is the mass fraction measured after melting and g i,0 is the target mass fraction of the i-th species if it were retained at 100%.…”

Section: Chemical Analysismentioning

confidence: 99%

“…and is largely stored in underground tanks [1]. Some of the tanks have leaked over the last few decades [2] and the waste must now be removed from the tanks and converted into a geologically stable waste form.…”

mentioning

confidence: 99%

“…Second, Tc is partly present in the waste as the pertechnetate ion ( 99 TcO 4 -), which is highly mobile in the environment. This represents a hazard to the waterways, communities, and ecology around the Hanford site [1]. Third, Tc is volatile at the temperatures where vitrification will be performed (1150 °C) so keeping it in the melt during the vitrification process has proven difficult [4,5].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Sodalite as a vehicle to increase Re retention in waste glass simulant during vitrification

Luksic

Riley

Parker

et al. 2016

Journal of Nuclear Materials

View full text Add to dashboard Cite

Technetium (Tc) retention during Hanford waste vitrification can be increased if the volatility can be controlled. Incorporating Tc into a thermally stable mineral phase, such as sodalite, is one way to achieve increased retention. Here, rhenium (Re)-bearing sodalite was tested as a vehicle to transport perrhenate (ReO 4-), a nonradioactive surrogate for pertechnetate (TcO 4-), into high-level (HLW) and low-activity waste (LAW) glass simulants. After melting HLW and LAW simulant feeds, the retention of Re in the glass was measured and compared with the Re retention in glass prepared from a feed containing Re 2 O 7. Phase analysis of sodalite in both these glasses across a profile of temperatures describes the durability of Resodalite during the feed-to-glass transition. The use of Re sodalite improved the Re retention by 21% for HLW glass and 85% for LAW glass demonstrating the potential improvement in Tcretention if TcO 4 were to be encapsulated in a Tc-sodalite prior to vitrification. 1 Introduction As a byproduct of the effort to produce plutonium for the US nuclear weapons arsenal from 1943 to 1988, a vast quantity of waste was produced at the Hanford Site in Washington State. This waste contains fission products and reagents from chemical separation processes

show abstract

Section: Chemical Analysismentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Sodalite as a vehicle to increase Re retention in waste glass simulant during vitrification

Luksic

Riley

Parker

et al. 2016

Journal of Nuclear Materials

View full text Add to dashboard Cite

show abstract

“…Technetium-99 (Tc-99) is one of the more challenging radionuclides present in Hanford low activity waste (LAW) because of its long half-life of 2.13 × 10 5 year and its penchant to become water-soluble pertechnetate. The pertechnetate ion (TcO 4 -), a stable form of oxidized Tc, is highly mobile in oxidized aqueous conditions and volatile at the temperatures of waste processing in glass melters [1,2], thus inhibiting Tc incorporation into the product glass [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Effect of Technetium-99 sources on its retention in low activity waste glass

Luksic

Kim

et al. 2018

Journal of Nuclear Materials

View full text Add to dashboard Cite

Small-scale crucible melting tests on simulated waste glass were performed with 9 technetium-99 (Tc-99) introduced as different species in a representative low activity waste simulant. The glass saw an increase in Tc-99 retention when TcO 2 •2H 2 O and various Tc-minerals containing reduced tetravalent Tc were used compared to tests in which pertechnetate with heptavalent Tc was used. We postulate that the increase of Tc retention is likely caused by different reaction paths for Tc incorporation into glass during early stages of melting, rather than the low volatility of reduced tetravalent Tc compounds, which has been a generally accepted idea. Additional studies are needed to clarify the exact mechanisms relevant to the effect of reduced Tc compounds on Tc incorporation into or volatilization from the glass melt.

show abstract

“…At Hanford, the inventory of Tc in the waste tanks is estimated at 26,500 Ci, and about 1000 Ci in the sediments and soils from leaks and direct discharge (Serne et al 2014). Among radioactive constituents present in the tank waste, Tc presents a unique challenge in that it is radiotoxic (β = 292 keV), has a long half-life (t 1/2 = 2.13×10 5 y), and exists predominantly in the liquid fraction of the alkaline tank waste, generally in the anionic form of pertechnetate TcO 4 -, which is highly volatile at low-activity waste (LAW) vitrification melter temperatures and mobile in the subsurface environment (Deutsch et al 2011). This makes immobilization of Tc into high-durability waste forms a critical technical challenge for nuclear waste management.…”

Section: Introductionmentioning

confidence: 99%