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SUMMARYThe subject analysis has been reviewed to determine if calculations are valid within stated assumptions. and suggest ways of reducing conservatism. Hand-calculations show that calculations have been performed correctly within the stated assumptions, although sludge density and uranium content have been used inconsistently in the text. VALIDATIONHand-calculations demonstrate that the subject results are reasonable, given the stated assumptions.A simple model suitable for hand-calculation assumes the following: (1) the t e m p e r a h drop across the first and second layers is zero, (2) volumetric beat generation is significant only in the third layer. (3) heat conduction is one-dimensional. and. (4) the bottom surface of the sludge is adiabatic while the top is fixed at IO C, and, (5) heat generation due to oxidation in the third layer can be r e p r m t e d by using one equivalent temperature in the oxidation rate law.A solution then for the temperature rise across the third layer is then:where Q"' is the volumetric heat generation due to decay heat and oxidation, L is the thickness of the third layer, and k is the sludge t h d conductivity. Figure 1 of the s u b w analysis gives L = 49 cm, and k = 0.6 Wk-m. Volumetric beat generation rate due to decay heat (m W/m ) is given by:where rsl is the third layer sludge density, Q is the heat generation rate in tefms of kWkg U, and U is the uranium concentration. Volumetric heat generation due to oxidation (W/m ) is given by:Q"', = 1000 rslmu (0.0068) 10(7.364 3016/r) where RM is rate multiplier, and T is an effective temperature. The effective temperature should yield the total volumetric heat generation rate in the third sludge layer. Appropriate v a l u~ for the analysis base case are: Q = 0.073 KW/ h4T U, RM = 0.82, U = 0.76 kg U/ kg SI, and rsl = 2300 kg/m . From Figure 1 of the subject analysis, the temperature of sludge varies between 283 and 325 K. which suggests that T might be somewhere in the range of 3 IO to 320 K. The effective temperature T was varied parametrically, as shown in Table 1 : 0.49The actual temperature rise across the third layer sludge is about 42 K, which is in fair agreement with results shown in Table 1.Total volumetric heat generation for the subject analysis was found from the temperature distribution shown in Table I, a total volumetric heat generation rate of 189 W/m3 gives a temperature rise of about 38 K, which agrees reasonably well with the 42 K value calculated for the subject analysis, and demonstrates that the temperature distribution in Figure 1 of the subject analysis is correct within stated assumptions. Disagreement between the hand-calculation and the subject analysis can be attributed to neglect of the fmt and second layers in the hand-calculation. COMMENTS AND SUGGESTIONSThe text on page A-10 is inconsistent. Decay heat is listed as 0.073 kW/MT U and from the SNF Project Technical Databook, WHC-SD-SNF-TI-015, this appears to be correct. But the uranium content of wet sludge should be used in calculations by cons...
SUMMARYThe subject analysis has been reviewed to determine if calculations are valid within stated assumptions. and suggest ways of reducing conservatism. Hand-calculations show that calculations have been performed correctly within the stated assumptions, although sludge density and uranium content have been used inconsistently in the text. VALIDATIONHand-calculations demonstrate that the subject results are reasonable, given the stated assumptions.A simple model suitable for hand-calculation assumes the following: (1) the t e m p e r a h drop across the first and second layers is zero, (2) volumetric beat generation is significant only in the third layer. (3) heat conduction is one-dimensional. and. (4) the bottom surface of the sludge is adiabatic while the top is fixed at IO C, and, (5) heat generation due to oxidation in the third layer can be r e p r m t e d by using one equivalent temperature in the oxidation rate law.A solution then for the temperature rise across the third layer is then:where Q"' is the volumetric heat generation due to decay heat and oxidation, L is the thickness of the third layer, and k is the sludge t h d conductivity. Figure 1 of the s u b w analysis gives L = 49 cm, and k = 0.6 Wk-m. Volumetric beat generation rate due to decay heat (m W/m ) is given by:where rsl is the third layer sludge density, Q is the heat generation rate in tefms of kWkg U, and U is the uranium concentration. Volumetric heat generation due to oxidation (W/m ) is given by:Q"', = 1000 rslmu (0.0068) 10(7.364 3016/r) where RM is rate multiplier, and T is an effective temperature. The effective temperature should yield the total volumetric heat generation rate in the third sludge layer. Appropriate v a l u~ for the analysis base case are: Q = 0.073 KW/ h4T U, RM = 0.82, U = 0.76 kg U/ kg SI, and rsl = 2300 kg/m . From Figure 1 of the subject analysis, the temperature of sludge varies between 283 and 325 K. which suggests that T might be somewhere in the range of 3 IO to 320 K. The effective temperature T was varied parametrically, as shown in Table 1 : 0.49The actual temperature rise across the third layer sludge is about 42 K, which is in fair agreement with results shown in Table 1.Total volumetric heat generation for the subject analysis was found from the temperature distribution shown in Table I, a total volumetric heat generation rate of 189 W/m3 gives a temperature rise of about 38 K, which agrees reasonably well with the 42 K value calculated for the subject analysis, and demonstrates that the temperature distribution in Figure 1 of the subject analysis is correct within stated assumptions. Disagreement between the hand-calculation and the subject analysis can be attributed to neglect of the fmt and second layers in the hand-calculation. COMMENTS AND SUGGESTIONSThe text on page A-10 is inconsistent. Decay heat is listed as 0.073 kW/MT U and from the SNF Project Technical Databook, WHC-SD-SNF-TI-015, this appears to be correct. But the uranium content of wet sludge should be used in calculations by cons...
ph: (865) 576-8401 fax: (865) 576 5728 email: reports@adonis.osti.gov Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161 ph: (800) 553-6847 fax: (703) 605-6900 email: orders@nits.fedworld.gov online ordering: http://www.ntis.gov/ordering.htm Abstract viiThese findings indicate that for solids very rich in uranium (≳70 to 80 wt%, dry basis), long-term storage under aerated non-agitated conditions will form a thin metaschoepite crust that is readily broken. The underlying material may compact somewhat with time, but, because little appreciable change in settled solids strength was seen after nearly a year of settling at 51°C in laboratory tests, little increase in strength, beyond that associated with any compaction, is anticipated during lower temperature but longer term storage.The observations from the 28-month settling test with uranium-rich genuine sludge and the studies with the uraninite oxidation suggest that metaschoepite crystal ripening and intergrowth may have been responsible for the uncommon strength found in the genuine sludge. In this case, the presence of relatively high amounts of metaschoepite within the settled solids layer likely was necessary to produce the strong product material. Based on these findings, K Basin sludges rich in metaschoepite [≳70 to 80 wt% U as U(VI), dry basis] may self-cement by Ostwald ripening to produce strong agglomerates similar to the behavior shown by the 96-13 sludge in the 28-month settling tests. Because of the low solubility of UO 2 , similar gains in strength by Ostwald ripening for UO 2 -rich sludge cannot occur. Under 51°C oxygenated conditions, a full KW containerized sludge simulant containing gibbsite, ferrihydrite, mordenite, organic ion exchange resin, Hanford sand, and ~50%/50% UO 2 /UO 3 ·2H 2 O decreased in settled solids volume by about 25% over 106 days while a parallel control test run in the absence of oxygen decreased only about 3%. The volume decrease coincided with the oxidation of UO 2 to UO 3 ·2H 2 O and may have been due to better solids packing or coagulation of non-uranium solids with the crystallizing UO 3 ·2H 2 O. However, even though the KW containerized sludge simulant compacted with time, the strength remained low. Under warm (30±5ºC) semi-oxic conditions, the uraninite in uranium-rich K Basin sludge samples oxidized to metaschoepite and other U(VI) phases after 9 years of hot cell storage (Delegard et al. 2007a).These findings mean that, unlike uraninite-rich sludges that form continuous layers or networks of product metaschoepite upon reaction with oxygen or which already have high metaschoepite concentrations, sludges more dilute in uraninite or metaschoepite likely will be unable to produce continuous metaschoepite layers that inhibit further oxidation or which self-cement to form highstrength agglomerates. Instead, the metaschoepite may act to coagulate non-uranium sludge solids and produce settled solids that are more tightly packed ...
Radioactive sludge was generated in the K-East Basin and K-West Basin fuel storage pools at the Hanford Site while irradiated uranium metal fuel elements from the N Reactor were being stored and packaged. The fuel has been removed from the K Basins, and currently, the sludge resides in the KW Basin in large underwater Engineered Containers. The first phase to the Sludge Treatment Project being led by CH2MHILL Plateau Remediation Company (CHPRC) is to retrieve and load the sludge into sludge transport and storage containers (STSCs) and transport the sludge to T Plant for interim storage. The STSCs will be stored inside T Plant cells that are equipped with secondary containment and leakdetection systems. The sludge is composed of a variety of particulate materials and water, including a fraction of reactive uranium metal particles that are a source of hydrogen gas. If a situation occurs where the reactive uranium metal particles settle out at the bottom of a container, previous studies have shown that a vessel-spanning gas layer above the uranium metal particles can develop and can push the overlying layer of sludge upward. The major concern, in addition to the general concern associated with the retention and release of a flammable gas such as hydrogen, is that if a vessel-spanning bubble (VSB) forms in an STSC, it may drive the overlying sludge material to the vents at the top of the container. Then it may be released from the container into the cell's secondary containment system at T Plant. A previous study demonstrated that sloped walls on vessels, both cylindrical coned-shaped vessels and rectangular vessels with rounded ends, provided an effective approach for disrupting a VSB by creating a release path for gas as a VSB began to rise. Based on the success of sloped-wall vessels, a similar concept is investigated here where a sloped fin is placed inside the vessel to create a release path for gas. A key potential advantage of using a sloped fin compared to a vessel with a sloped wall is that a small fin decreases the volume of a vessel available for sludge storage by a very small fraction compared to a cone-shaped vessel. The purpose of this study is to quantify the capability of sloped fins to disrupt VSBs and to conduct sufficient tests to estimate the performance of fins in full-scale STSCs. Experiments were conducted with a range of fin shapes to determine what slope and width were sufficient to disrupt VSBs. Additional tests were conducted to demonstrate how the fin performance scales with the sludge layer thickness and the sludge strength, density, and vessel diameter based on the gravity yield parameter, which is a dimensionless ratio of the force necessary to yield the sludge to its weight. (a) Further experiments evaluated the difference between vessels with flat and 2:1 elliptical bottoms and a number of different simulants, including the KW container sludge simulant (complete), which was developed to match actual K-Basin sludge. Testing was conducted in 5-in., 10-in., and 23-in.-diameter vessels to...
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