[Federal Register Volume 74, Number 58 (Friday, March 27, 2009)]
[Notices]
[Pages 13482-13483]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-6845]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-271; NRC-2009-0121]
Entergy Nuclear Operations, Inc.; Vermont Yankee Nuclear Power
Station; Exemption
1.0 Background
Entergy Nuclear Operations, Inc. (Entergy or the licensee) is the
holder of Facility Operating License No. DPR-28, which authorizes
operation of the Vermont Yankee Nuclear Power Station (VY). The license
provides, among other things, that the facility is subject to all
rules, regulations, and orders of the Nuclear Regulatory Commission
(NRC or the Commission) now or hereafter in effect.
The facility consists of a boiling-water reactor located in Windham
County, Vermont.
2.0 Request/Action
Title 10 of the Code of Federal Regulations (10 CFR), Part 50,
Section 50.48, requires that nuclear power plants that were licensed
before January 1, 1979, of which VY is one, must satisfy the
requirements of 10 CFR Part 50, Appendix R, Section III.G.2, which
requires to have a minimum of 20 feet separation between redundant
cable trays.
In an NRC letter dated December 1, 1986, the NRC granted the
licensee the exemption from the provisions of 10 CFR Part 50, Appendix
R, Section III.G.2, which in part permitted a reduction in minimum
separation distance between cable trays in the northwest corner of Fire
Zone RB-3 of the reactor building to 18 feet. VY has identified that
the actual minimum physical separation distance between the cable trays
is actually 17 feet-7.5 inches.
In summary, the letter dated July 11, 2008, Agencywide Documents
Access and Management System (ADAMS) accession number ML082030154, as
supplemented on November 20, 2008, ADAMS accession number ML083370180,
Entergy on behalf of VY, requested a revision to the exemption from the
provisions of 10 CFR Part 50, Appendix R, Section III.G.2, dated
December 1, 1986 (ML011620492), which in part permitted a reduction in
minimum separation distance between cable trays in the northwest corner
of Fire Zone RB-3 of the Reactor Building to 18 feet. VY has requested
a revision of the existing exemption to permit the actual minimum
separation distance of 17 feet-7.5 inches.
3.0 Discussion
Pursuant to 10 CFR 50.12, the Commission may, upon application by
any interested person or upon its own initiative, grant exemptions from
the requirements of 10 CFR Part 50 when (1) the exemptions are
authorized by law, will not present an undue risk to public health or
safety, and are consistent with the common defense and security; and
(2) when special circumstances are present. One of these special
circumstances, described in 10 CFR 50.12(a)(2)(ii), is that the
application of the regulation is not necessary to achieve the
underlying purpose of the rule.
The underlying purpose of Subsection III.G.2 of 10 CFR Part 50,
Appendix R, is to ensure that one of the redundant trains necessary to
achieve and maintain hot shutdown conditions remains free of fire
damage in the event of a fire.
The NRC staff reviewed the licensee's evaluation in support of the
subject exemption request and concludes that the further reduction in
minimum separation distance is sufficient to maintain an adequate level
of safety to meet the requirements of 10 CFR 50.12(a)(2)(ii) in that
the application of the regulation is not necessary to achieve the
underlying purpose of the rule.
Authorized by Law
This exemption would permit a reduced minimum separation distance
of 17 feet-7.5 inches, instead of ``more than 20 feet'' between cable
trays in Fire Zone RB-3, elevation 252 feet, provided all other passive
and active forms of protection (e.g., lack of combustible fuel loading
or fire hazards, fire detectors and automatic fire suppression system)
are provided and maintained in accordance with III.G.2. As stated
above, 10 CFR 50.12 allows the NRC to grant exemptions from the
requirements of 10 CFR Part 50. The NRC staff has determined that
granting of the licensee's proposed exemption will not result in a
violation of the Atomic Energy Act of 1954, as amended, or the
[[Page 13483]]
Commission's regulations. Therefore, the exemption is authorized by
law.
No Undue Risk to Public Health and Safety
One of the underlying purposes of 10 CFR Part 50, Appendix R
Section III.G is to protect safe shutdown capability. This is done by
ensuring that one train of systems necessary to achieve and maintain
hot shutdown conditions from either the control room or emergency
control station(s) is free of fire damage. III.G.2 provides the
following means to ensure that a redundant train of safe shutdown
equipment is free of fire damage, where redundant trains are located in
the same fire area:
a. Separation of cables and equipment by a fire barrier having a 3-
hour rating,
b. Separation of cables and equipment by a horizontal distance of
more than 20 feet with no intervening combustibles or fire hazards and
with fire detectors and an automatic fire suppression system in the
fire area, or
c. Enclosure of cables and equipment in a fire barrier having a 1-
hour rating and with fire detectors and an automatic fire suppression
system in the fire area.
Entergy has indicated that the cable trays will be separated by a
minimum distance of 17 feet-7.5 inches for a horizontal distance of
approximately 10 feet and that the remaining length of cable trays will
be separated by more than 17 feet-7.5 inches. Entergy has also
indicated that transient combustibles and hot work controls have been
enhanced since the exemption was originally granted. This was
accomplished by designating Fire Zone RB-3 as a ``Level 2'' combustible
control area, which limits combustibles to moderate quantities and hot
work requires prior review and approval of a fire protection engineer.
Additionally, Entergy has stated that a pre-action automatic
sprinkler system is provided beneath the lowest level of cable trays
and above the top level of cable trays in Fire Zone RB-3 and that
manual suppression equipment is provided throughout Fire Zone RB-3 in
the form of accessible fire hose stations and portable fire
extinguishers. A fire detection system is provided in the form of
Ionization-type smoke detectors.
According to Entergy, the fire protection systems are functionally
unchanged from what was previously included in the December 1, 1986,
evaluation. The licensee has indicated that 1-hour 3M Interam fire
barriers were installed to protect certain raceways in the northwest
corner of elevation 252 feet however; no credit for the barriers has
been requested as part of this exemption.
Based on the above, the exemption to allow the reduced minimum
separation distance of 17 feet-7.5 inches in lieu of the 20 feet
dimension specified in III.G.2 a, b, and c, does not increase the
probability of postulated accidents or undue risk. Based on the
combination of a lack of combustible fuel loading and ignition sources,
room configuration and the separation distance of 17 feet-7.5 inches,
the overall level of protection and defense in depth has been shown to
meet or exceed the intent of the requirements included in III.G.2 and
equivalent with regard to safe shutdown capability following a fire.
Therefore, there is no additional risk to public health and safety.
Consistent With Common Defense and Security
The proposed exemption would permit a reduced minimum separation
distance between cable trays in a select area in lieu of meeting the
separation requirements specified in III.G.2. This change has no
relation to security issues. Therefore, the common defense and security
is not impacted by this exemption.
Special Circumstances
Special circumstances, in accordance with 10 CFR 50.12(a)(2)(ii),
are present whenever application of the regulation in the particular
circumstances is not necessary to achieve the underlying purpose of the
rule. Part of the underlying purpose of 10 CFR Part 50, Appendix R
Section III.G is to assure safe shutdown capability. Entergy states
that the active and passive fire protection features that were included
in the original exemption remain functionally unchanged. This review
determined that the reduction in minimum separation distance does not
adversely affect the level of safety at the plant given the physical
configuration of the cable trays, existing suppression and detection
systems and the lack of combustible fuel loading in the area. The
combination of these safeguards is sufficient to maintain safe shutdown
capability in the event of a fire even at the reduced separation
distance of 17 feet-7.5 inches. Since the underlying purpose of 10 CFR
Part 50, Appendix R Section III.G to protect safe shutdown capability
is achieved, the special circumstances required by 10 CFR
50.12(a)(2)(ii) for the granting of an exemption from 10 CFR Part 50,
Appendix R Section III.G.2 exist.
4.0 Conclusion
Accordingly, the Commission has determined that special
circumstances are present and that, pursuant to 10 CFR 50.12(a), the
exemption is authorized by law, will not present an undue risk to the
public health and safety, and is consistent with the common defense and
security levels intended by the rule for Nuclear Power Plants.
Therefore, the Commission hereby grants Entergy an exemption from the
requirements of III.G.2 b of 10 CFR Part 50, Appendix R, which is
required by 10 CFR 50.48(b) for plants licensed to operate before
January 1, 1979, to VY.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will not have a significant effect on the
quality of the human environment (74 FR 11612).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 19th day of March 2009.
For the Nuclear Regulatory Commission.
Robert A. Nelson,
Acting Director, Division of Operating Reactor Licensing, Office of
Nuclear Reactor Regulation.
[FR Doc. E9-6845 Filed 3-26-09; 8:45 am]
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