Design Report for the ½ Scale Air-Cooled RCCS Tests in the Natural convection Shutdown heat removal Test Facility (NSTF)

Lisowski, Darius; Farmer, M. T.; Lomperski, S.; Kilsdonk, D. J.; Bremer, Nathan; Aeschlimann, R. W.

doi:10.2172/1184668

Cited by 5 publications

(16 citation statements)

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“…The mesh convergence sensitivity study showed that the simulation results are highly dependent on the mesh refinement at the fluid-solid boundary, calling for very fine meshes near the reactor vessel surface due to the large temperature gradients at the wall. To examine the feasibility of an air-cooled RCCS option for advanced gas-cooled reactors, an experimental program was established at Argonne National Laboratory [58] in the early 2000s which revitalized the Natural convection Shutdown heat removal Test Facility (NSTF) built previously for RVACS testing in the 1980s. Compared to the legacy NSTF, the modern NSTF stood 26-m in total height and was designed to represent a 1:2 scale model of the primary features of the General Atomic (GA) RCCS design for the MHTGR [59].…”

Section: Air-cooled Rccsmentioning

confidence: 99%

“…To examine the feasibility of an air-cooled RCCS option for advanced gas-cooled reactors, an experimental program was established at Argonne National Laboratory [58] in the early 2000s which revitalized the Natural convection Shutdown heat removal Test Facility (NSTF) built previously for RVACS testing in the 1980s. Compared to the legacy NSTF, the modern NSTF stood 26-m in total height and was designed to represent a 1:2 scale model of the primary features of the General Atomic (GA) RCCS design for the MHTGR [59]. The test section contained twelve riser ducts and served as the primary flow area for cooling within the heated cavity, Figure 48.…”

Section: Air-cooled Rccsmentioning

confidence: 99%

“…Testing performed on the modern, air-based RCCS of the NSTF at Argonne examined system response and heat removal performance with blocked riser channels [58]. Their test began by establishing steady-state operating conditions at the normal operating heat load, which defined a full-scale load of 700 kWt, or 26.16 kWt in the test facility, scaled ½ axially from the full-scale RCCS design for the GA-MHTGR.…”

Section: Blockage Of Riser Flow Channelsmentioning

confidence: 99%

“…Studies performed with the modern air-based NSTF at Argonne also examined the effect of a chimney "short-circuit". In this scenario, a break occurs between adjacent ductwork that allows incoming cold air to by-pass the heated section and instead flows directly back into the exhaust stream [58]. For this test case, a variable damper valve was installed between adjacent ductwork, where one duct serves as the primary fresh air intake and the other as the exhaust discharge.…”

Section: Blockage Of Riser Flow Channelsmentioning

confidence: 99%

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An Overview of Non-LWR Vessel Cooling Systems for Passive Decay Heat Removal (Technical Letter Final Report)

Lisowski¹,

Lv²,

Alexandreanu³

et al. 2021

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The following report provides a technical review of various reactor vessel cooling system (VCS) concepts under consideration for decay heat removal (DHR) in non-light water advanced reactor designs. This review focuses on ex-vessel designs, including the Reactor Cavity Cooling System (RCCS), the Reactor Vessel Auxiliary Cooling System (RVACS), and hybrid iterations, using both air and water cooling to achieve their heat removal function. Based on a literature review of publicly available sources published between 1979 and 2021, a technical summary is presented detailing existing and planned VCS design options, their applicability to specific reactor type, and review of authored research and development studies. Following an assessment of the availability of data and modeling tools, an evaluation was performed analyzing their likely performance during normal, degraded, and accident conditions, including reliability, stability, and longevity.With renewed consideration of air-based DHR systems by some US vendors, there is a need to fully understand the complexities inherent to natural circulation systems, and more importantly, how they may influence safety-related heat removal functions and system performance. For DHR systems that rely on air-based mode of cooling, this entails quantification of the impacts of low flow conditions during start-up, relative elevations of inlet and outlet ducts for below-grade installations, effects of the use of multiple parallel chimneys for redundancy, and impact of weather conditions at the plant site. For systems relying on water-based mode cooling, reliance on limited coolant inventory in an event of pipe break or extended duration accident scenarios, sensitivities related to stability of boiling flow and heat transfer conditions, and quantification of full-scale structural vibrations on balance of plant structures are among the complicating factors. Paperwork Reduction Act StatementThis report does not contain information collection requirements and, therefore, is not subject to the requirements of the Paperwork Reduction Act of 1995 (44 United States Code [U.S.C.] 3501 et seq.). Public Protection NotificationThe U.S. Nuclear Regulatory Commission (NRC) may not conduct or sponsor, and a person is not required to respond to, a request for information or an information collection requirement unless the requesting document displays a current valid Office of Management and Budget (OMB) control number.

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Section: Air-cooled Rccsmentioning

confidence: 99%

Section: Air-cooled Rccsmentioning

confidence: 99%

Section: Blockage Of Riser Flow Channelsmentioning

confidence: 99%

Section: Blockage Of Riser Flow Channelsmentioning

confidence: 99%

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An Overview of Non-LWR Vessel Cooling Systems for Passive Decay Heat Removal (Technical Letter Final Report)

Lisowski¹,

Lv²,

Alexandreanu³

et al. 2021

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“…Measurements of system mass flow rates, differential pressure drop, surface and gas temperatures, among others, are included in this suite. A summary is provided in Table 1, with additional details such as the heater configuration and insulation properties provided in earlier works by the authors [6,7]. While it is expected that thermal radiation will be the primary mode of heat transfer, the heated cavity (essentially an internal enclosed environment) allows natural circulation cells to develop and grow.…”

Section: Full Scale Design Conceptmentioning

confidence: 99%

Experimental observations of natural circulation flow in the NSTF

Lisowski¹,

Kraus²,

Bucknor³

et al. 2016

Nuclear Engineering and Design

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A ½ scale test facility has been constructed at Argonne National Laboratory (ANL) to study the heat removal performance and natural circulation flow patterns in a Reactor Cavity Cooling System (RCCS). Our test facility, the Natural convection Shutdown heat removal Test Facility (NSTF), supports the broader goal of developing an inherently safe and fully passive ex-vessel decay heat removal for advanced reactor designs. The project, initiated in 2010 to support the Advanced Reactor Technologies (ART), Small Modular Reactor (SMR), and Next Generation Nuclear Plant (NGNP) programs, has been conducting experimental operations since early 2014. The following paper provides a summary of some primary design features of the 26-m tall test facility along with a description of the data acquisition suite that guides our experimental practices. Specifics of the distributed fiber optic temperature measurements will be discussed, which introduces an unparalleled level of data density that has never before been implemented in a large scale natural circulation test facility. Results from our test series will then be presented, which provide insight into the thermal hydraulic behavior at steady-state and transient conditions for varying heat flux levels and exhaust chimney configuration states.

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Ambient and building condition effects modeling of air-cooled natural circulation systems

Lisowski

Bucknor

et al. 2018

Applied Thermal Engineering

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Design Report for the ½ Scale Air-Cooled RCCS Tests in the Natural convection Shutdown heat removal Test Facility (NSTF)

Cited by 5 publications

References 0 publications

An Overview of Non-LWR Vessel Cooling Systems for Passive Decay Heat Removal (Technical Letter Final Report)

An Overview of Non-LWR Vessel Cooling Systems for Passive Decay Heat Removal (Technical Letter Final Report)

Experimental observations of natural circulation flow in the NSTF

Ambient and building condition effects modeling of air-cooled natural circulation systems

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