The University of Missouri (MU) has been working in conjunction with Argonne National Laboratory (ANL) in the National Nuclear Security Administration (NNSA) Material Management and Minimization (M3) Reactor Conversion Program to support conversion of the University of Missouri-Columbia Research Reactor (MURR®) from highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel. MURR is one of five U.S. High Performance Research Reactors (USHPRR) plus a critical facility that plans to convert to the use of LEU fuel. ANL/RTR/TM-18/16 Safety Analysis of the Mo-99 Production Upgrade to the University of Missouri Research Reactor (MURR) with Highly Enriched and Low-Enriched Uranium Fuel ii ANL/RTR/TM-18/16 Safety Analysis of the Mo-99 Production Upgrade to the University of Missouri Research Reactor (MURR) with Highly Enriched and Low-Enriched Uranium Fuel iv installed. Thus, the upgrade causes a change in the location of the maximum HEU fuel temperature resulting from the limiting LOFA, which is consistent with the shift in the core power distribution that occurs due to the upgrade. For the LEU core, the minimum margin to the fuel temperature safety limit for the limiting LOFA with the 2017-RBM-99 upgrade is 232 °C and occurs in an EOL fuel plate. This is the same margin as was predicted for the limiting LOFA for the PSAR analysis. The location of the minimum margin moves from plate 23 of the fuel element in core position 8 in the PSAR analysis to plate 23 of the fuel element in core position 4 with the upgrade. With more margin than the other scenarios, all LOFA transient results are considered to have very adequate margins to the burnupdependent fuel temperature safety limit. Because there is no change to the HEU or LEU nominal fuel element loadings and an overall negligible effect on the fuel burnup as a result of the 2017-RBM-99 upgrade, the radiological consequences of the maximum hypothetical accident and fuel handling accident were not evaluated in this work. As found in the PSAR analysis, for any event where a release is considered in the current HEU SAR, the radiological consequences after conversion remain lower than the regulatory limits. In summary, the Mo-99 production upgrade to MURR with the 2017-RBM-99 device has been found to cause a shift in the core power distribution for both HEU and LEU cores relative to the PSAR analysis. The predicted steady-state margins to flow instability with the upgrade are adequate for both HEU and LEU cores. The margins with the upgrade are lower than those predicted in the PSAR analysis for both HEU and LEU, but the margin for LEU is larger than that for HEU. For postulated transient accidents, the upgrade causes a slight decrease in the minimum margin to a fuel temperature safety limit based on the fuel blister threshold temperature. There is a 9 °C reduction in the safety margin for HEU for the most limiting accident evaluated under conditions specified in NUREG-1537. For a reference LEU core, the minimum safety margin for the most limiting transient accident with ...

BackgroundThis study aimed to evaluate the effectiveness of gancyclovir (GCV) treatment for severe cytomegalovirus (CMV)-associated pneumonia in immunocompetent children.MethodWe enrolled patients with CMV-associated severe pneumonia admitted to the Vietnam National Hospital of Pediatrics, Hanoi, Vietnam, from January 2010 to December 2011. On admission, though respiratory bacteria and viruses were not detected in tracheal aspirates, more than 5 × 103 copies/mL of CMV-DNA were detected in both tracheal aspirates and in blood plasma. GCV was given intravenously at a dose of 10 mg/kg/24 h for a duration of 14 days at most. The dose was then reduced to 5 mg/kg/24 h until CMV-DNA was not detected in plasma. The main study variables included clinical symptoms, complete blood count, hepatic and renal function, chest X-ray, CMV viral load, duration of GCV treatment and outcome.ResultsForty-three patients were enrolled in the study. The median age of patients was 57 (interquartile range [IQR] 45–85) days. Clinical and laboratory findings included anemia (67.4%), leukocytosis (90.7%), hepatosplenomegaly (60.5%), elevated liver enzymes (74.4%), decreased ratio of CD4: CD8-positive T lymphocytes (69.4%), and decreased serum IgG concentration (25.7%). The median duration of GCV treatment was 12 days (IQR 7-21). Thirty-seven patients (86.0%) showed normal chest X-rays at the end of treatment. One infant died (2.3%); the other children (97.7%) were discharged in good condition. There was no severe toxicity associated with GCV treatment.ConclusionGCV is safe and effective for the treatment of severe CMV-associated pneumonia in children.

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