[Federal Register Volume 66, Number 198 (Friday, October 12, 2001)]
[Proposed Rules]
[Pages 52065-52066]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-25672]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 66, No. 198 / Friday, October 12, 2001 /
Proposed Rules
[[Page 52065]]
NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
[Docket No. PRM-50-73]
Robert H. Leyse; Receipt of Petition for Rulemaking
AGENCY: Nuclear Regulatory Commission.
ACTION: Petition for rulemaking; notice of receipt.
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SUMMARY: The Nuclear Regulatory Commission (NRC) is publishing for
public comment a notice of receipt of a petition for rulemaking, dated
September 4, 2001, which was filed with the Commission by Robert H.
Leyse. The petition was docketed by the NRC on September 4, 2001, and
has been assigned Docket No. PRM-50-73. The petitioner requests that
the NRC amend its regulations on the acceptance criteria for emergency
core cooling systems for light-water nuclear power reactors to address
the impact of crud on cooling capability during a fast-moving, large-
break, loss-of-coolant accident (LOCA).
DATES: Submit comments by December 26, 2001. Comments received after
this date will be considered if it is practical to do so, but the
Commission is able to assure consideration only for comments received
on or before this date.
ADDRESSES: Submit written comments to the Secretary of the Commission,
U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001,
Attention: Rulemakings and Adjudications Staff. Deliver comments to:
11555 Rockville Pike, Rockville, Maryland, between 7:30 a.m. and 4:15
p.m. Federal workdays.
For a copy of the petition, write to Michael T. Lesar, Chief, Rules
and Directives Branch, Division of Administrative Services, Office of
Administration, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001.
You may also provide comments via the NRC's interactive rulemaking
website at http://ruleforum.llnl.gov. This site provides the capability
to upload comments as files (any format), if your web browser supports
that function. For information about the interactive rulemaking
website, contact Ms. Carol Gallagher, 301-415-5905 (e-mail:
[email protected]).
The petition and copies of comments received may be inspected and
copied for a fee at the NRC Public Document Room,11555 Rockville Pike,
Public File Area O1F21, Rockville, Maryland. Copies of comments
received are also available through the NRC's Agencywide Documents
Access and Management System (ADAMS), which provides text and image
files of NRC's public documents. These documents may be accessed
through the NRC's Public Electronic Reading Room on the Internet at
http://www.nrc.gov/NRC/ADAMS/index.html. If you do not have access to
ADAMS or if there are problems in accessing the documents located in
ADAMS contact the NRC Public Document Room (PDR) Reference staff at 1-
800-397-4209, 301-415-4737or by e-mail to [email protected].
FOR FURTHER INFORMATION CONTACT: Michael T. Lesar, Chief, Rules and
Directives Branch, Division of Administrative Services, Office of
Administration, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001, Telephone: 301-415-7163 or Toll Free: 800-368-5642.
SUPPLEMENTARY INFORMATION:
The Petitioners Request
The petitioner requests that the NRC amend Sec. 50.46(a)(1)(i) and
Appendix K to Part 50 to address the impact of crud on cooling
capability during a fast-moving (large-break), LOCA.
Background
The petitioner states that Sec. 50.46 and Appendix K to part 50 do
not address the impact of crud on coolability during a fast-moving
(large-break) LOCA. The petitioner states that a certain licensed power
reactor has operated with unusually heavy crud deposits on many of the
fuel pins. These crud deposits were identified and partially classified
during a refueling outage. The petitioner states that if a fast-moving
(large-break) LOCA had occurred before the shutdown for refueling,
extensive blockage of the flow channels within the fuel bundles would
have developed. The petitioner further states that, during blowdown,
the redistribution of crud into any or all of the several restricted
channels would result in the substantial flow blockage. The petitioner
states that these restricted flow channels include at least the
following items within the fuel bundles: the spacer grids, the mixing
vanes attached to spacer grids, and the regions of ballooned and burst
fuel cladding. The petitioner states that the consequent degradation of
coolability would have resulted in a rapid deterioration of defense in
depth. Under these conditions, the unusually heavy crud deposits on the
fuel pins would have threatened the integrity of all of the barriers
that in total comprise defense in depth.
The petitioner believes that it could be argued that significant
crud deposits would lead to an extensive amount of fuel failure during
operation at [full] power. The petitioner believes that the amount of
failed fuel would then lead to a decision to shut down the reactor as
the inventory of radioactive material in the reactor coolant reached
the limits that are allowed by the Technical Specifications. According
to the petitioner, operating experience reveals that it is possible to
operate a light-water reactor within the applicable Technical
Specifications even though unusually heavy crud deposits are present on
the fuel pins.
The Petitioner's Conclusions
The petitioner believes that the deficiencies in Part 50 must be
corrected to retain defense in depth. Accordingly, elements in
Sec. 50.46 concerning comparisons to applicable experimental data must
be revised to include the impact of crud on deposits on fuel pins.
Also, the following paragraphs in Appendix K to part 50, should be
revised to include the impact of crud deposits on fuel pins:
I.B. Swelling and Rupture of the Cladding and Fuel Rod Thermal
Parameters;
I.C.2 Frictional Pressure Drops;
I.C.4 Critical Heat Flux;
I.C.5 Post-CHF Heat Transfer Correlations;
I.C.7 Core Flow Distribution During Blowdown;
I.D.3 Calculation of Reflood Rate for Pressurized Water Reactors;
I.D.6 Convective Heat Transfer Coefficients for Boiling Water
[[Page 52066]]
Reactor Fuel Rods Under Spray Cooling; and
I.D.7 The Boiling-Water Reactor Channel Box Under Spray Cooling.
II.1.a The documentation requirements in this paragraph should include
a description of each evaluation model used for estimation of the
effects of crud deposits on fuel pins.
Dated at Rockville, Maryland, this 5th day of October, 2001.
For the Nuclear Regulatory Commission.
Annette L. Vietti-Cook,
Secretary of the Commission.
[FR Doc. 01-25672 Filed 10-11-01; 8:45 am]
BILLING CODE 7590-01-P