Preparation and Heat-Treatment of DWPF Simulants With and Without Co-Precipitated Noble Metals

Koopman, David C.

doi:10.2172/881443

Cited by 1 publication

(9 citation statements)

References 3 publications

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two versions of Sludge Batch 3 simulant were prepared at the Aiken County Technology Laboratory, ACTL, Koopman (2005c). One ACTL simulant included co-precipitated noble metals and the other did not.…”

Section: Analytical Results For Simulants Used In Phase II Testsmentioning

confidence: 99%

“…The tables in this section primarily summarize data needed for the stoichiometric acid calculation for the SRAT cycle, section 2.4. Additional compositional details for the four simulants can be found in Koopman (2005c).…”

Section: Analytical Results For Simulants Used In Phase II Testsmentioning

confidence: 99%

“…Considerable total inorganic carbon, TIC, data was obtained as described in Koopman (2005c). This was averaged later to determine the best estimate of TIC for each simulant run.…”

Section: Analytical Results For Simulants Used In Phase II Testsmentioning

confidence: 99%

“…These two simulants, with and without co-precipitated noble metals, were used to test the impact of the form of noble metals on hydrogen generation. Simulant preparation is reported in Koopman (2005c).…”

Section: Overview Of Current Hydrogen Generation Programmentioning

confidence: 99%

“…If hydrogen generation results were nearly identical for the co-precipitated noble metal SRAT and the 100% trimmed noble metal SRAT cycles, then this would indicate no significant difference between trimmed and co-precipitated noble metals. A supporting run would be made trimmed at 65% of the nominal noble metal concentrations to show the sensitivity of the 100% trimmed noble metal results to the concentrations of the noble metals and to cover potential analytical uncertainties in the measured concentrations of the co-precipitated noble metals, Koopman (2005c).…”

Section: Srat Test Matrixmentioning

confidence: 99%

See 4 more Smart Citations

DWPF Hydrogen Generation Study-Form of Noble Metal SRAT Testing

Bannochie¹

2005

View full text Add to dashboard Cite

EXECUTIVE SUMMARYThe Defense Waste Processing Facility, DWPF, has requested that the Savannah River National Laboratory, SRNL, investigate the factors that contribute to hydrogen generation to determine if current conservatism in setting the DWPF processing window can be reduced. A phased program has been undertaken to increase understanding of the factors that influence hydrogen generation in the DWPF Chemical Process Cell, CPC. The hydrogen generation in the CPC is primarily due to noble metal catalyzed decomposition of formic acid with a minor contribution from radiolytic processes. Noble metals have historically been added as trim chemicals to process simulations. The present study investigated the potential conservatism that might be present from adding the catalytic species as trim chemicals to the final sludge simulant versus co-precipitating the noble metals into the insoluble sludge solids matrix.Two sludge simulants were obtained, one with co-precipitated noble metals and one without noble metals. Co-precipitated noble metals were expected to better match real waste behavior than using trimmed noble metals during CPC simulations. Portions of both sludge simulants were held at 97°C for about eight hours to qualitatively simulate the effects of long term storage on particle morphology and speciation. The two original and two heat-treated sludge simulants were then used as feeds to Sludge Receipt and Adjustment Tank, SRAT, process simulations. Testing was done at relatively high acid stoichiometries, ~175%, and without mercury in order to ensure significant hydrogen generation. Hydrogen generation rates were monitored during processing to assess the impact of the form of noble metals. The following observations were made on the data:• Co-precipitated noble metal simulant processed similarly to trimmed noble metal simulant in most respects, such as nitrite to nitrate conversion, formate destruction, and pH, but differently with respect to hydrogen generation.The peak hydrogen generation rate occurred three to five hours later for the regular and heat-treated co-precipitated noble metal slurries than for the slurries with trimmed noble metals. The peak hydrogen generation rate was lower during processing of the co-precipitated noble metal simulant relative to the trimmed noble metal simulant data. Trimmed noble metals appeared to be conservative relative to co-precipitated noble metals under the conditions of these tests as long as the peak hydrogen generation rate occurred early in the SRAT boiling period.• If the peak hydrogen generation rate with trimmed noble metals is near or above the DWPF limit, and if the peak occurs late in the SRAT cycle, then a potential SME cycle hydrogen generation rate issue could be anticipated when using co-precipitated noble metals, since the peak is expected to be delayed relative to trimmed noble metals.• The peak hydrogen generation rate increased from about 1.3 to about 3.7 lbs H 2 /hr on the range of 170-190% stoichiometry, or about 0.1 lbs. H 2 /hr per % change in the...

show abstract

Section: Analytical Results For Simulants Used In Phase II Testsmentioning

confidence: 99%

Section: Analytical Results For Simulants Used In Phase II Testsmentioning

confidence: 99%

“…Considerable total inorganic carbon, TIC, data was obtained as described in Koopman (2005c). This was averaged later to determine the best estimate of TIC for each simulant run.…”

Section: Analytical Results For Simulants Used In Phase II Testsmentioning

confidence: 99%

Section: Overview Of Current Hydrogen Generation Programmentioning

confidence: 99%

Section: Srat Test Matrixmentioning

confidence: 99%

See 3 more Smart Citations