[Federal Register Volume 64, Number 208 (Thursday, October 28, 1999)] [Notices] [Pages 58107-58108] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 99-28227] ----------------------------------------------------------------------- NUCLEAR REGULATORY COMMISSION Selection of Sample Rate and Computer Wordlength in Digital Instrumentation and Control Systems, Availability of Draft NUREG for Comment
Agency
Nuclear Regulatory Commission.
Action
Notice of availability.
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Summary
The Nuclear Regulatory Commission is announcing the completion and availability of Draft NUREG-1709, ``Selection of Sample Rate and Computer Wordlength in Digital Instrumentation and Control Systems,'' dated August 1999.
Addresses
Draft NUREG-1709, is available for inspection and copying for a fee at the NRC Public Document Room, 2120 L Street NW (Lower Level), Washington DC 20555-0001. A free single copy of Draft NUREG- 1709, to the extent of supply, may be requested by writing to Reproduction and Distribution Services Section, OCIO, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.
For Further Information Contact
Terry Jackson, Division of Engineering Technology, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001. Telephone: 301-415- 6486.
Supplementary Information
Digital sampling of analog signals adds two types of errors, aliasing and finite wordlength error, to the sampled version of the signal. Aliasing is characterized by high frequency components misrepresented as low frequency components in the sampled signal. It is greatly influenced by the sample rate, and may lead to degraded performance in monitoring, alarm, control, and protection systems. Since
computer wordlengths are finite in length, digital systems are limited in their capability to represent real number values. Finite wordlength errors related to round-off, truncation, and data conversion have the potential to adversely impact the performance of digital instrumentation and control (I&C) systems. The Office of Nuclear Regulatory Research has investigated the technical bases and review guidance regarding aliasing and finite wordlength errors in nuclear facilities. Hazards associated with these errors are minimized through proper design and selection of sample rates and computer wordlengths. Draft NUREG-1709 provides the regulatory background, theoretical information, practical issues, best engineering practices, review guidance, and examples associated with sample rate and computer wordlength selection. This information is used by NRC staff to identify proper treatment of aliasing and finite wordlength error in digital I&C systems. While draft NUREG-1709 is intended for NRC staff use, the NRC realizes that licensees and vendors may reference the NUREG for their particular I&C development. Because of its impact on I&C development, the NRC is requesting comments on draft NUREG-1709. The comment period will last until March 1, 1999, at which time the NRC will consider the comments and pursue a final version. To send comments on draft NUREG- 1709, refer to the comment instructions at the front of the report. Comments may also be sent to the NRC Home page, as detailed below.
Electronic Access
Draft NUREG-1709, is available electronically by visiting NRC's Home Page (www.nrc.gov) and choosing ``Reference Library,'' then ``NRC (NUREG) report number,'' then ``NRC Staff Reports,'' and then ``NUREG-1709.'' Instructions for sending comments electronically are included with the document at the web site.
www.nrc.govDated at Rockville, Maryland, this 24th day of August, 1999.
For the Nuclear Regulatory Commission. Sher Bahadur, Chief, Engineering Research Applications Branch, Division of Engineering Technology, Office of Nuclear Regulatory Research. [FR Doc. 99-28227 Filed 10-27-99; 8:45 am] BILLING CODE 7590-01-P