[Federal Register Volume 69, Number 32 (Wednesday, February 18, 2004)]
[Page 7661]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-3441]



Notice of Clarification to Steam Generator Tube Integrity Event 
Reporting Guideline in NUREG-1022, ``Event Reporting Guidelines 10 CFR 
50.72 and 50.73''

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice of clarification in reporting guideline for steam 
generator tube integrity event.


SUMMARY: The U.S. Nuclear Regulatory Commission plans to make a 
clarification in the reporting guideline for serious steam generator 
tube degradation contained within Revision 2 to NUREG-1022, ``Event 
Reporting Guidelines 10 CFR 50.72 and 50.73.'' The NRC intends to issue 
an errata to NUREG-1022, Revision 2. The purpose of this clarification 
is to ensure that the NRC receives timely notification of serious steam 
generator tube degradation.

SUPPLEMENTARY INFORMATION: In NUREG-1022, Revision 2, ``Event Reporting 
Guidelines 10 CFR 50.72 and 50.73,'' steam generator tube degradation 
is characterized in Section 3.2.4(A)(3) as being seriously degraded if 
the tubing fails to meet the following two performance criteria: (A) 
Steam generator tubing shall retain structural integrity over the full 
range of normal operating conditions (including startup, operation in 
the power range, hot standby, and cooldown and all anticipated 
transients included in the design specification) and design basis 
accidents. This includes retaining a margin of 3.0 against burst under 
normal steady state full power operation and a margin of 1.4 against 
burst under the limiting design basis accident concurrent with a safe 
shutdown earthquake. (B) The primary to secondary accident induced 
leakage rate for the limiting design basis accident, other than a steam 
generator tube rupture, shall not exceed the leakage rate assumed in 
the accident analysis in terms of total leakage rate for all steam 
generators and leakage rate for an individual steam generator. The 
licensing basis accident analyses typically assume a 1 gallon per 
minute primary to secondary leak rate per steam generator, except for 
specific types of degradation at specific locations where the tubes are 
confined, as approved by the NRC and enumerated in conjunction with the 
list of approved repair criteria in the licensee's design basis 
documents. The first performance criteria is commonly referred to as 
the structural integrity performance criteria and the second criteria 
is commonly referred to as the accident induced leakage performance 
criteria. As written, NUREG-1022, Revision 2 implies that the principal 
safety barrier (i.e., the steam generator tubes in this case) would not 
be considered seriously degraded if it had either structural or leakage 
integrity. This is contradictory to existing NRC regulations which 
require, in part, that the reactor coolant pressure boundary (which 
includes the steam generator tubes) be designed to permit periodic 
inspection and testing of important areas and features to assess both 
their structural and leak-tight integrity (refer to General Design 
Criterion 32 of Appendix A to 10 CFR part 50) and be designed and 
tested so as to have an extremely low probability of abnormal leakage, 
of rapidly propagating failure, and of gross rupture (refer to General 
Design Criterion 14 of Appendix A to 10 CFR part 50). The regulations, 
therefore, indicate that both structural and leakage integrity criteria 
must be satisfied and not meeting either one of the two performance 
criteria should constitute serious degradation of the principal safety 
barrier. Accordingly, steam generator tube degradation should be 
considered serious if either of the two criteria specified in Section 
3.2.4(A)(3) of NUREG-1022, Revision 2, are not satisfied.
    The intended clarification involves changing the wording in Section 
3.2.4(A)(3) of NUREG-1022, Revision 2 (page 39) from ``Steam generator 
tube degradation is considered serious if the tubing fails to meet the 
following two performance criteria'' to ``Steam generator tube 
degradation is considered serious if the tubing fails to meet either of 
the following two performance criteria.''
    The NRC will consider any comments it receives pertaining to this 
intended change in NUREG-1022, Revision 2.

DATES: Comment period expires March 19, 2004. Comments submitted after 
this date will be considered if it is practical to do so, but assurance 
of consideration cannot be given except for comments received on or 
before this date.

ADDRESSES: Submit written comments to the Chief, Rules and Directives 
Branch, Division of Administrative Services, Office of Administration, 
U.S. Nuclear Regulatory Commission, Mail Stop T6-D59, Washington, DC 
20555-0001, and cite the publication date and page number of this 
Federal Register notice. Written comments may also be delivered to NRC 
Headquarters, 11545 Rockville Pike (Room T6-D59), Rockville, Maryland, 
between 7:30 a.m. and 4:15 p.m. on Federal workdays.

FOR FURTHER INFORMATION, CONTACT: Samuel Lee at (301) 415-1061 or by E-
mail to ssl@nrc.gov, or Ken Karwoski at (301) 415-2752 or by e-mail to 

    Dated at Rockville, Maryland, this 10th day of February, 2004.
    For the Nuclear Regulatory Commission.
William D. Beckner,
Chief, Reactor Operations Branch, Division of Inspection Program 
Management, Office of Nuclear Reactor Regulation.
[FR Doc. 04-3441 Filed 2-17-04; 8:45 am]