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Developing a new regulatory framework for advanced reactors: Update on Part 53
White
The American Nuclear Society’s Risk-informed, Performance-based Principles and Policy Committee (RP3C) on March 29 held another presentation in its monthly Community of Practice (CoP) series. The presenter, Patrick White with the Nuclear Innovation Alliance (NIA), talked about the current status of efforts to develop a new regulatory framework for advanced reactors—known as 10 CFR Part 53 or simply Part 53. White serves as the research director of the NIA, where he leads their research as well as analysis-based stakeholder and policymaker engagement and education. White’s March 29 presentation is publicly available on YouTube and at ANS’s publication platform Nuclear Science and Technology Open Research (NSTOR).
RP3C chair N. Prasad Kadambi opened the CoP with brief introductory remarks about the RP3C before he welcomed White as the session’s presenter.
White covered three main topics: the history of the existing regulatory frameworks for new reactors, progress to date on the development of the Part 53 rule for advanced reactors, and the current status and next steps for the Part 53 rulemaking process.
Mohamed S. El-Genk, Cheng Gao
Nuclear Technology | Volume 125 | Number 1 | January 1999 | Pages 52-69
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT99-A2932
Articles are hosted by Taylor and Francis Online.
Quenching experiments were conducted to investigate pool boiling of saturated water on downward-facing aluminum and 303e stainless steel hemispheres. Test sections had an outer diameter of 0.152 m and a wall thickness of 0.020 m. Destabilization of film boiling and wetting of the stainless steel surface occurred earlier than with aluminum (15 s versus 92 s), at 20 K higher wall superheat and ~10% higher minimum film boiling heat flux qmin. Wetting of the stainless steel surface occurred first near the edge of the test section and then gradually propagated azimuthally inward, followed by the maximum heat flux (MHF) front. Conversely, wetting of the aluminum surface occurred first at the lowermost position ( = 0 deg) and then propagated azimuthally outward. The azimuthal propagation of the MHF front on the stainless steel surface (~5 deg/s for 60 deg < < 90 deg decreasing to ~1.8 deg/s for 10 deg < < 60 deg and then increasing slightly to ~2 deg/s for 0 deg < < 60 deg) was much slower than on aluminum (~22.5 deg/s on average). The MHF front traversed the entire stainless steel boiling surface in ~40 s versus only 4 s for aluminum. When MHF for the latter first occurred at = 0 deg, the radial and near-boiling surface azimuthal temperature gradients were 4 K/mm and 0.6 K/deg, respectively, compared to 12 to 15 K/mm and 1.5 K/deg for stainless steel. For both surfaces, the MHF and qmin values displayed parabolic dependencies on azimuthal angle. The local MHF at = 0 deg was 0.81 and 0.40 MW/m2 for aluminum and stainless steel, respectively, decreasing with increased azimuthal angle to minimums of 0.47 and 0.256 MW/m2 at = 45 deg. Beyond 45 deg, the local MHF increased with increased azimuthal angle to 0.76 and 0.47 MW/m2, respectively, near the edge of the surface ( = 80 deg). However, the wall superheats corresponding to the MHF (30 K for aluminum and 80 K for stainless steel) and the qmin (125 K for aluminum and 145 K for stainless steel) were independent of azimuthal angle.