Information Notice 2007-08, Potential Vulnerabilities of Time-Reliant Computer-Based Systems Due to Change in Daylight Saving Time Dates

Potential Vulnerabilities of Time-Reliant Computer-Based Systems Due to Change in Daylight Saving Time Dates

ML070510034
Person / Time
Issue date:	02/28/2007
From:	Michael Case, Schlueter J NRC/FSME/DMSSA, NRC/NRR/ADRA/DPR
To:
References
IN-07-008
Download: ML070510034 (3)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

OFFICE OF FEDERAL AND STATE MATERIALS

AND ENVIRONMENTAL MANAGEMENT PROGRAMS

OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS

WASHINGTON, D.C. 20555-0001 February 28, 2007 NRC INFORMATION NOTICE 2007-08: POTENTIAL VULNERABILITIES OF TIME-

RELIANT COMPUTER-BASED SYSTEMS DUE

TO CHANGE IN DAYLIGHT SAVING TIME

DATES

ADDRESSEES

All U. S. Nuclear Regulatory Commission (NRC) licensees and all Agreement State Radiation

Control Program Directors and State Liaison Officers.

PURPOSE

The NRC is issuing this information notice (IN) to inform addressees of the potential

vulnerabilities of computer-based systems and devices due to the change in the start and end

dates of Daylight Savings Time (DST) in 2007. This change could potentially cause problems

for computer-based systems and devices that employ time-dependent processes that have not

been set to synchronize with the 2007 DST change. This IN is issued to ensure that all

recipients are aware of the start and end date changes to DST and the potential for problems

this change could cause.

It is expected that recipients will review the information for applicability to their facilities and

consider actions, as appropriate, to avoid any problems. However, suggestions contained in

this information notice are not NRC requirements; therefore, no specific action or written

response is required.

DESCRIPTION OF CIRCUMSTANCES

The Energy Policy Act of 2005 included a change in start and end dates of DST beginning in

2007. This year, DST will be extended by a month starting about three weeks sooner, and

ending a week later than usual. Specifically, DST will begin on March 11, 2007, and end on

November 4, 2007, therefore, clocks will be set ahead 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> on March 11, 2007, and will be

set back 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> on November 4, 2007.

DISCUSSION

There are many computer-based systems that may be vulnerable to the 2007 DST changes.

Examples include software to perform system control, data logging, and time-related

calculations. The DST changes may also have impacts on other time-dependent computer

systems, such as corporate and local Information Technology systems, communication

systems, and security systems.

CONTACT

This IN requires no specific action or written response. If you have any questions about the

information in this notice, please contact the technical contact below, or the appropriate

regional office.

/RA/ /RA by TQuay for/

Janet R. Schlueter Michael J. Case, Director

Division of Materials Safety Division of Policy and Rulemaking

and State Agreements Office of Nuclear Reactor Regulation

Office of Federal and State Materials and

Environmental Management Programs

Technical Contact:

Matthew Chiramal, NRR/DE

(301) 415-2845 E-mail: mxc@nrc.gov

Note: NRC generic communications may be found on the NRC public web site, http://www.nrc.gov under Electronic Reading Room/Document Collections.

DISCUSSION

There are many computer-based systems that may be vulnerable to the 2007 DST changes.

Examples include software to perform system control, data logging, and time-related

calculations. The DST changes may also have impacts on other time-dependent computer

systems, such as corporate and local Information Technology systems, communication

systems, and security systems.

CONTACT

This IN requires no specific action or written response. If you have any questions about the

information in this notice, please contact the technical contact below, or the appropriate

regional office.

/RA/ /RA by TQuay for/

Janet R. Schlueter Michael J. Case, Director

Division of Materials Safety Division of Policy and Rulemaking

and State Agreements Office of Nuclear Reactor Regulation

Office of Federal and State Materials and

Environmental Management Programs

Technical Contact:

Matthew Chiramal, NRR/DE

(301) 415-2845 E-mail: mxc@nrc.gov

Note: NRC generic communications may be found on the NRC public web site, http://www.nrc.gov under Electronic Reading Room/Document Collections.

ADAMS Accession Number: ML070510034 OFFICE DE PGCB:DPR PGCB:DPR D:DE BC:PGCB:DPR D:DPR

NAME MChiramal JRobinson CHawes PHiland CJackson MJCase

DATE 02/20/07 02/21/07 02/28/07 02/20/07 02/28/07 02/28/07 OFFICE Tech.Editor FSME FSME FSME NMSS NMSS

NAME CClark (email) AMcintosh PRathbun JSchlueter RPierson EBrach (email)

DATE 02/22/07 02/21/07 02/23/07 02/27/07 02/21/07 02/26/07 OFFICE NMSS

NAME LKokajko

DATE 02/22/07 OFFICIAL RECORD COPY