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The Maricopa County Department of Public Health (MCDPH) Sexually Transmitted Disease (STD) Clinic remained operational during a 6-week statewide Coronavirus Disease 2019 (COVID-19) Stay-at-Home Order. The present study sought to evaluate the effect of the Stay-at-Home Order on countywide STD reporting and uptake of sexual health services. We compared countywide daily median STD reporting and MCDPH STD clinic attendance across 3 timeframes; (1) Pre-Lockdown (01/01/2020–03/30/2020); (2) Lockdown (03/31/2020–05/15/2020); and (3) Post-Lockdown (05/16/2020–12/31/2020). STD reporting was characterized as incident chlamydia, gonorrhea, and primary and secondary syphilis. Clinic attendance was characterized as clients visiting through express testing or provider visits. Differences in STD reporting and clinic attendance were evaluated using non-parametric testing. Comparing Pre-Lockdown to Lockdown, we observed significant declines in the daily median chlamydia case reporting (−22%) and clinic express testing attendance (−29%). Comparing Lockdown to Post-Lockdown, we observed significant increases in daily median chlamydia and gonorrhea case reporting (+20%, +15%; respectively) and clinic express testing and provider visits (+42%, +20%; respectively). No significant difference was observed in countywide syphilis reporting across the 3 timeframes. Declines in STD reporting were observed countywide during the lockdown and were concurrent with declines in attendance observed at the MCDPH STD Clinic. Maintenance of clinic operations during the lockdown allowed for continued uptake of STD testing, diagnosis, treatment, and partner services. This study of sexual health care utilization at the public STD clinic in Maricopa County, Arizona, found reduced testing and provider visits contributed to lower countywide STD reporting during the Arizona COVID-19 Stay-at-Home Order.

The paper presents recent activities conducted at the Paul Scherrer Institut (PSI) in relation to the development and validation of an integral calculation methodology based on CASMO-4/SIMULATE-3/MCNPX for accurate estimations of the fast neutron fluence (FNF) accumulated on reactor pressure vessels and internals of the operating Swiss BWRs. With this computational scheme, the default neutron source is set up at the pin-by-pin level with realistic spectrum specifications based on the actual reactor cycle-specific data from validated reference CASMO-4/SIMULATE-3 core analysis models. On this basis, MCNPX models are then applied for optimized calculations of the fast neutron flux at the RPV or at any other location of interest including e.g. at surveillance dosimeters. In that framework, the validation studies conducted so far have included one dosimeter set irradiated in a BWR/6 reactor during two relatively recent operating cycles. Although this first analysis revealed a satisfactory performance when comparing the calculation results to measured data, it was considered necessary to proceed with further sensitivity/optimization studies combined with an enlarged validation basis (i.e. using additional dosimeter sets) in order to strengthen the overall confidence in the scheme both at the qualitative and quantitative level. A summary of the recent progress achieved in these directions is presented in this paper. To start, recalling that BWRs are characterized by very complex and heterogeneous fuel assembly and core designs (e.g. pins with different enrichments and burnable absorber loading, partial length rods, fuel assemblies of different types in the core), the impact of such heterogeneities on FNF estimations is under investigation in order to determine the level of modeling details required for accurate computational schemes to be used for long-term evaluations of modern BWR core designs. Next, additional validation studies based on experimental dosimeter data obtained from the same BWR/6 reactor are presented. These enlarged validation studies involve the analysis of four dosimeter sets, each irradiated during one cycle (including the 3 first reactor operation cycles), and subsequently analyzed at the PSI Hot Lab shortly after the dosimeters extraction. All these additional validation studies are conducted using both the JEFF-3.1.1 and the ENDF/B-VII.0 continuous-energy neutron data libraries in order to assess the sensitivity of the PSI BWR computational scheme also upon the employed nuclear data.

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The determination of the subcriticality level for source-driven systems is an important problem that can be handled by several deterministic methods developed for the interpretation of flux signals in pulsed experiments. The paper compares the performance of several methods for different physical characteristics of the system considered and for different durations of the source pulse. The effects of the subcriticality level and of the experimental uncertainty are also investigated. Furthermore, an analysis of the influence of spatial effects is carried out. The study gives some indications on the most suitable method in a specific experimental configuration pointing out at the situations where non-conservative evaluations of the reactivity can be expected, i.e. when the system effective multiplication constant is underestimated.

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