[Federal Register Volume 71, Number 60 (Wednesday, March 29, 2006)]
[Notices]
[Pages 15770-15772]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-4586]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-348]
Southern Nuclear Operating Company; Joseph M. Farley Nuclear
Power Plant, Unit 1; Exemption
1.0 Background
The Southern Nuclear Operating Company (SNC, the licensee) is the
holder of Renewed Facility Operating License No. NPF-2 which authorizes
operation of Joseph M. Farley Nuclear Power Plant (FNP), Unit 1. The
license provides, among other things, that the facility is subject to
all rules, regulations, and orders of the Nuclear Regulatory Commission
(NRC, the Commission) now or hereafter in effect.
The facility consists of a pressurized-water reactor located in
Houston County, Alabama.
2.0 Request/Action
Title 10 of the Code of Federal Regulations (10 CFR) Part 50,
Appendix R, ``Fire Protection Program for Nuclear Power Facilities
Operating Prior to January 1, 1979,'' establishes fire protection
features required to satisfy General Design Criterion 3, ``Fire
protection,'' of Appendix A to10 CFR Part 50 with respect to certain
generic issues for nuclear power plants licensed to operate prior to
January 1, 1979. FNP, Unit 1 was licensed to operate prior to January
1, 1979. Therefore, FNP, Unit 1 is directly subject to Appendix R.
By letter dated January 19, 2005, as supplemented by letters dated
June 9 (two letters) and November 18, 2005, SNC, the licensee for FNP,
Unit 1, submitted a request for a permanent exemption from 10 CFR
Appendix R, Section III.G.2, pertaining to FNP, Unit 1 (SNC letters NL-
04-2357, NL-05-0937, NL-05-0960 and NL-05-1975, respectively).
Specifically, 10 CFR Appendix R, Section III.G.2, would require the use
of a 1-hour rated fire barrier for protection of certain safe shutdown
control circuits located in Fire Areas 1-013 and 1-042. In lieu of
providing such 1-hour rated fire barriers, the licensee proposes the
use of fire-rated electrical cable produced by Meggitt Safety System,
Inc., (previously known as Whittaker Electronic Resources Unit of
Whittaker Electronic Systems) for several cables in Fire Areas 1-013
and 1-042 associated with safe shutdown control circuits.
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. These special circumstances
are described in 10 CFR 50.12(a)(2)(ii), in that the application of
these regulations is not necessary to achieve the underlying purpose of
the rule.
The underlying purpose of Appendix R, Section III.G, is to provide
features capable of limiting fire damage so that: (1) 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; and (2) systems necessary to achieve and maintain cold shutdown
from either the control room or emergency control station(s) can be
repaired within 72 hours.
3.1 Overview of Approach Used by Licensee
For this specific fire protection application, SNC proposes plant
modifications to use 1-hour fire-rated electrical cable in lieu of a 1-
hour rated fire barrier as required by 10 CFR Part 50, Appendix R,
Section III.G.2. Section III.G.2 of 10 CFR Part 50, Appendix R,
provides fire protection requirements for electrical cables located
within the same fire area whose failure could cause the maloperation of
redundant trains of systems necessary to achieve and maintain hot
shutdown conditions. These areas are required to have protection
features such that one of the redundant trains will be free of fire
damage in the event of a fire. One method, described in Section
III.G.2, for ensuring compliance with this requirement is to enclose
the cable and equipment and associated non-safety circuits of one
redundant train in a 1-hour rated fire barrier. In addition, an area-
wide automatic fire suppression and detection system shall be installed
in the fire area.
A postulated fire in Fire Area 1-013 or 1-042 could cause loss of
offsite power; both fire areas contain cable bus ducts from the startup
transformers to both redundant trains of the 4 kilovolt (KV) Appendix R
safe shutdown (SSD) busses. A postulated fire in either of these fire
areas could also potentially impact the function of the Train B 4 KV
Emergency Diesel Generator (EDG) 1B control circuitry. The majority of
the Train A onsite electrical power system components required for
Appendix R SSD are not located in Fire Area 1-013 or 1-042. The
following Train A onsite power system related SSD circuits
[[Page 15771]]
located in Fire Areas 1-013 and 1-042 will be protected by a 1-hour
fire-rated electrical cable along with area-wide automatic fire
suppression and detection:
1. Protection of control circuitry that could potentially disable
the supply of the onsite power from the Train A 4KV EDGs 1-2A and 1-C,
or disable supply of 7 Train A onsite power due to inadvertent loading
of electronic switching system (ESS) loads onto EDG 1-C:
(a) The control interlocks for the automatic alignment of the
Train A Swing EDG 1C Incoming Breaker 1-DH07 or 2-DH07 to provide
onsite AC power due to loss of offsite power to the shutdown buses.
(b) The control interlocks for the automatic alignment of the
Train A Swing EDG 1-2A Incoming Breaker 1-DF08 or 2-DF08 to provide
onsite AC power due to loss of offsite power to the shutdown buses.
(c) The control interlocks for the automatic alignment of Unit 1
600V Load Center 1D Breaker 1-ED13 or Unit 2 600V Load Center 2D
Breaker 2-ED13 to MCC 1S (power to the Train A Swing EDG 1-2A
auxiliaries) so that the MCC is aligned to the same DG 1-2A.
(d) The control interlocks from Unit 2 ESS Sequencer that blocks
Unit 1 ESS Sequencer on a Unit 2 safety injection actuation signal
(This signal is to prevent inadvertent loading of ESS loads on
smaller DG 1C).
(e) The control interlock from Unit 1 ESS Sequencer that blocks
Unit 2 ESS Sequencer on a Unit 1 safety injection actuation signal
(This signal is to prevent inadvertent loading of ESS loads on
smaller DG 1C).
2. Protection of the control circuitry that could potentially
disable the operation of the 4KV power supply breakers to the Train A
Component Cooling Water Pump 1C, Train A Charging Pump 1A, and Train A
Motor-Driven Auxiliary Feed-Water Pump 1A.
3. Protection of the control circuitry that could potentially
disable the operation of the 600V load center power supply breaker to
Train A Pressurizer Heater Group 1A.
A 1-hour rated fire barrier as described in Section III.G.2 of 10
CFR Part 50, Appendix R is not provided. Instead, these credited Train
A components will utilize fire-rated electrical cables (Mineral
Insulated (MI) cables). This fire-rated electrical cable has been
tested in accordance with American Society for Testing Materials (ASTM)
E-119, ``Standard Test Methods for Fire Tests of Building Construction
Materials.''
3.2 Technical Evaluation
3.2.1 Test Results
The NRC staff reviewed this issue with respect to determining that
the fire-rated electrical cables would be capable of providing an
equivalent level of protection as would be provided by a 1-hour rated
fire barrier as required by 10 CFR part 50, Appendix R, Section
III.G.2.
The licensee provided copies of the test report, ``Appendix R, One-
Hour Fire Resistive Control Cable Test,'' dated August 11, 2004, in its
submittal. The cables in Farley, Unit 1 are used as control circuit
applications and are rated at 125 volts direct-current (VDC). The
licensee's report, listed above, includes the fire test performance
results for 8 Conductor 12 AWG Meggitt Safety Systems
electrical cable with factory splices and several support systems and
attachment methods, when exposed to the ASTM E-119 time-temperature
heating curve for a period of 1 hour.
3.2.2 Megger Testing
The fire-rated electrical cables at FNP were tested for use in low
voltage control circuits. Megger Testing was conducted at 500 VDC, to
obtain conductor-to-conductor and conductor-to-ground insulation
resistance values, before the fire test, during the fire test, and
after the hose stream test. To ensure that the conductor-to-conductor
and conductor-to-ground insulation resistance (IR) readings were
obtained for all conductor combinations at the peak ASTM E-119 1-hour
test temperature, the first test was extended for an additional 38
minutes and 12 seconds with the furnace temperature held as close as
possible to 1700 degrees Farenheit until all IR values were recorded.
Obtaining insulation resistance values during the fire test by the test
method applied provided conservative test results that meet the fire
Megger Testing requirements of GL 86-10, Supplement 1, for the FNP
specific 1-hour rated control cable application. The NRC staff finds,
based on the Megger Testing, that the insulation resistance values are
acceptable for the specific application at FNP, Unit 1.
3.2.3 Minimum Insulation Resistance Value
The licensee completed a plant circuit-specific analysis and
concluded that the control circuit protective devices will not trip
during a fire event with an IR value of 5.7 mega-ohms/foot (M'[Omega]/
ft). The minimum IR value recorded during the fire test was 0.8
M'[Omega], and with 24.176 feet of cable inside the furnace, that
equated to 19.3 M'[Omega]/ft. This far exceeds the FNP-specific minimum
acceptance value of 5.7 M'[Omega]/ft.
The NRC staff concludes that, based on the information provided,
the minimum IR value recorded during testing is acceptable for the
specific application at FNP, Unit 1.
3.2.4 Mechanical Damage Protection
Rated 1-hour electrical cable raceway fire barriers are tested in a
furnace and subject to a hose stream test that ensures the raceway and
the barriers will stay in place following a fire exposure. The fire-
rated electrical cables were tested in a furnace and subjected to a
hose stream. Since the fire-rated electrical cables themselves are the
barriers, any mechanical damage that occurs to the cables may cause the
cables to fail. The licensee's letter dated June 9, 2005, stated that
the areas where the fire-rated electrical cables are routed are
protected with area-wide automatic fire suppression and detection
systems, as required by Appendix R Section III.G.2.c. In addition, the
routing for each fire-rated electrical cable was established by plant
walk-downs to protect against potential physical hazards. The licensee
stated that the fire-rated electrical cables are also safety-related
and will be installed to meet the FNP routing requirements for Class 1E
cable protection from physical hazards. The fire-rated electrical
cables are only routed in safety-related Class 1 structures, and all
safety-related and nonsafety-related equipment and components in these
structures are seismically supported.
The NRC staff concludes, based on the information provided, that
there is adequate protection from mechanical damage to demonstrate
equivalence to a raceway fire barrier system for the specific
application at FNP, Unit 1.
3.2.5 Galvanized Supports
When in contact with galvanized supports, fire-resistive electrical
cable produced by Meggitt Safety Systems, Inc. has been reported to
experience degradation due to liquid metal embrittlement. This
degradation occurs at the positions where the galvanized supports are
in direct contact with the stainless steel cable jacket. Section 4,
subsection j of Meggitt Safety Systems engineering document,
``Unpacking, Inspection, Installation and Standard Practices for 8/C
12 AWG Si 2400 Fire-Rated Cable For J.M. Farley Nuclear Plant,
Revision D,'' states that ``Si Fire Cable may be routed in cable trays;
Stainless steel trays are recommended. Cable should not be installed in
galvanized trays and should NOT be in direct contact with galvanized or
aluminum trays or structures.''
The NRC staff concludes, based on the information provided in the
engineering document, that the installation standard
[[Page 15772]]
will adequately address the concern with galvanized supports for the
specific application at FNP, Unit 1.
3.2.6 Defense-in-Depth
The following are the fire protection defense-in-depth objectives:
(1) To prevent fires from starting; (2) to detect rapidly, control, and
extinguish promptly those fires that do occur; and (3) to provide
protection for structures, systems, and components important to safety
so that a fire that is not promptly extinguished by the fire
suppression activities will not prevent the safe shutdown of the plant.
The licensee stated that Fire Areas 1-013 and 1-042 are provided with
area-wide automatic fire suppression and detection systems. The use of
fire-rated electrical cables is a substitute for 1-hour rated fire
barriers that are required by 10 CFR Part 50, Appendix R, and supports
the third defense-in-depth objective. For this specific application,
the licensee has demonstrated that the fire-rated electrical cables
used are a suitable alternative to the 1-hour rated fire barrier as
required by 10 CFR part 50, Appendix R.
4.0 Conclusion
The NRC staff concludes that, on the bases of the discussions in
the sections above, for the specific application of this material, the
licensee has adequately demonstrated that this fire-rated electrical
cable will perform in an equivalent manner when compared to a rated
barrier for this use. The NRC staff also concludes that the use of the
MI cable for these purposes, meets the underlying purpose of Appendix R
and, that, therefore special circumstances are present. Accordingly,
the Commission has determined 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. Therefore, the Commission hereby grants Southern Nuclear
Operating Company an exemption from the requirements to 10 CFR Part 50,
Appendix R, Section III.G.2, to the extent that it requires protection
of cables of one redundant train of safe shutdown equipment by a 1-hour
rated fire barrier, for Fire Areas 1-013 and 1-042. The fire-rated
electrical cables provide an equivalent level of protection necessary
to achieve the underlying purpose of the rule for Joseph M. Farley
Nuclear Plant, Unit 1.
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 (71 FR 12219, March 9, 2006).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 22nd day of March 2006.
For the Nuclear Regulatory Commission.
Edwin M. Hackett,
Acting Director, Division of Operating Reactor Licensing, Office of
Nuclear Reactor Regulation.
[FR Doc. E6-4586 Filed 3-28-06; 8:45 am]
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