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Design of infiltration basin
Published in James C. Y. Guo, Urban Flood Mitigation and Stormwater Management, 2017
A sand filter (Figure 18.2) is a shallow, wide, flat infiltration bed that is located at the outfall point of a parking lot, automobile service station, business area, etc. A dry well is a vertical tube with backfilled gravels and rocks to store and then to transfer the intercepted stormwater into the groundwater table. A dry well shall be deep enough to effectively recharge the local groundwater table.
Novel concept for a filtered containment venting system with an ionic liquid to remove organic iodine (1)-proof of concept for organic iodine removal
Published in Journal of Nuclear Science and Technology, 2023
Sohei Fukui, Kazushige Ishida, Motoi Tanaka, Kazuo Tominaga
In the case of boiling water reactors (BWRs), wet well or dry well venting is conducted to reduce the release of radionuclides into the environment at the time of a SA. Some radionuclides are removed by scrubbing the vent gas in the suppression pool. The vent gas containing the remaining radionuclides flows to the filter vessel. The ratio of iodine initially contained in the vent gas to iodine that remains after passing through a FCVS defined as the decontamination factor (DF) and DF of 100 for particle and inorganic iodine obtained by the wet well venting through the suppression pool is described in NUREG-1465 [13]. For an advanced BWR (ABWR) with a thermal output of 3,926 MWt, we estimated that about 0.8 kg of organic iodine would be produced and released into the PCV. This organic iodine in the PCV would then be released to the organic iodine filter vessel via the filter vessel and then DF of 50 for the organic iodine will be attained. Filter vessel for an ABWR is designed about 5 m diameter, 10 m height, and 3 m scrubbing water depth. At the time of a SA, design conditions of filter vessel are 0.1–0.6 MPa[gage] design pressure, 393–433 K design temperature, 6–8 m3 s−1 design gas flow rate, and 0.38–0.64 m s−1 design gas flow velocity.
What is the role of green stormwater infrastructure in managing extreme precipitation events?
Published in Sustainable and Resilient Infrastructure, 2021
Lauren E. McPhillips, Marissa Matsler, Bernice R. Rosenzweig, Yeowon Kim
Several of the cities examined have stronger requirements. Miami requires retention of the 5-year, 24-hr precipitation event on residential and commercial development. It also specifically focuses on exfiltration trenches, grassed swales, dry detention basins, or underground drainage wells. Portland requires retention of the 10-year, 24-hr event, regardless of the implementation mechanism for GSI (i.e., post-construction of new or re-development or CSO control). Portland prioritizes runoff reduction via impervious surface reductions, and then vegetated infiltration as a top choice for GSI; in areas with infiltration restrictions, detention may be permitted, given that peak flow control requirements are met (which are discussed in the following paragraph). Phoenix has the most extensive runoff reduction guidance of the cities considered with a requirement to retain the 100-year, 2-hr precipitation event on site for new land development projects. This requirement is typically met by using retention basins, which are designed to promote infiltration, and may sometimes have a dry well to help facilitate infiltration (McPhillips & Matsler, 2018). In select cases in Phoenix, detention facilities may be permitted and retention and/or treatment of a 13 mm water quality volume is required, which equates to roughly a 1-year, 1-hr event (City of Phoenix, 2011).
Estimation of reactor vessel failure by metallic interaction in Fukushima Daiichi Nuclear Power Plant accident
Published in Journal of Nuclear Science and Technology, 2021
Ayumi Itoh, Shintaro Yasui, Yoshinao Kobayashi
Figure 4 shows the measured RPV pressure data (green circles) with the calculated RPV failure time. In the case of Unit 1, the cooling function was completely lost immediately after the tsunami owing to the station blackout. Thereafter, the water in the RPV evaporated with a discharge of steam to the suppression pool (S/C) and/or dry-well (D/W), resulting in a decrease in the water level, exposure of fuel to the gas phase, temperature escalation of core materials triggering chemical reactions, core melt, and relocation. The international benchmarking project [4] after the incident also confirmed this accident progression.