Regulatory Treatment of Nonsafety Systems in Passive Advanced Light-Water Reactors PUBLIC ACCESS

[+] Author Affiliations
Thomas Scarbrough

U.S. Nuclear Regulatory Commission, Washington, DC

Paper No. NRC2014-5010, pp. 305-315; 11 pages
  • ASME/NRC 2014 12th Valves, Pumps, and Inservice Testing Symposium
  • ASME/NRC 2014 12th Valves, Pumps, and Inservice Testing Symposium
  • Rockville, Maryland, USA, June 23–25, 2014
  • Conference Sponsors: ASME
  • ISBN: 978-0-7918-9932-8
  • Compilation Copyright © 2019 ASME


Some new nuclear power plants have advanced light-water reactor (ALWR) designs with passive safety systems that rely on natural forces, such as density differences, gravity, and stored energy, to supply safety-injection water and to provide reactor-core and containment cooling. Active systems in such passive ALWR designs are categorized as nonsafety systems with limited exceptions. Active systems in passive ALWR designs provide the first line of defense to reduce challenges to the passive systems in the event of a transient at the nuclear power plant. Active systems that provide a defense-in-depth function in passive ALWR designs need not meet all of the acceptance criteria for safety-related systems. However, there should be a high level of confidence that these active systems will be available and reliable when challenged. Multiple activities will provide confidence in the capability of these active systems to perform their defense-in-depth functions; these are collectively referred to as the Regulatory Treatment of Nonsafety Systems (RTNSS) program. The U.S. Nuclear Regulatory Commission (NRC) addresses policy and technical issues associated with RTNSS equipment in passive ALWRs in several documents. This paper discusses the NRC staff’s review of pumps, valves, and dynamic restraints within the scope of the RTNSS program in passive ALWRs.

Paper published with permission.

Compilation Copyright © 2019 ASME
This article is only available in the PDF format.



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In