[Federal Register Volume 69, Number 159 (Wednesday, August 18, 2004)]
[Notices]
[Pages 51334-51336]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-18885]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-263]


Nuclear Management Company, LLC; Monticello Nuclear Generating 
Plant; Exemption

1.0 Background

    The Nuclear Management Company, LLC (NMC) is the holder of Facility 
Operating License No. DPR-22, which authorizes operation of the 
Monticello Nuclear Generating Plant (MNGP). NMC provides, among other 
things, that the facility is subject to all rules, regulations, and 
orders of the U.S. Nuclear Regulatory Commission (NRC, the Commission) 
now or hereafter in effect. The facility consists of a boiling-water 
reactor located in Wright County, Minnesota.

2.0 Request/Action

    Title 10 of the Code of Federal Regulations (10 CFR), Section 
50.48(b), ``Fire Protection,'' specifies that Appendix R, ``Fire 
Protection Program for Nuclear Power Facilities Operating Prior to 
January 1, 1979,'' established fire protection requirements to satisfy 
10 CFR Part 50, Appendix A, General Design Criterion 3, ``Fire 
Protection.'' Appendix R, Section III.G.2.b, specifies that (1) Cables 
and equipment and associated non-safety circuits of redundant trains be 
separated by a horizontal distance of more than 20 feet with no 
intervening combustible or fire hazards, and (2) fire detectors and an 
automatic fire suppression system be installed in the fire area.
    In Northern States Power's (the licensee for Monticello at that 
time) letter of June 30, 1982, it requested a permanent exemption from 
the automatic suppression system requirements of Appendix R, Section 
III.G.2.b for the suppression pool torus area. Northern States Power 
justified the exemption by stating the following:

    * * * the area is separated from other plant areas by three-hour 
fire rated barriers. Fire protection consists of smoke detectors, 
manual hose stations, and portable fire extinguishers. The only 
redundant safe shutdown equipment in the area consists of 
instrumentation for measuring the water temperature and level in the 
torus. The redundant trains are separated by one hundred feet and 
are free of intervening combustibles. Essentially no combustible 
material is stored or located in the area. Furthermore, all surfaces 
are concrete except for the torus, which is steel. All cables are 
installed in conduit.

    The technical requirements of Section III.G.2 were not met in fire 
zone 1F (the torus compartment at MNGP) because cables and components 
of redundant shutdown divisions were not protected with area-wide 
automatic sprinkler system.
    The NRC's letter of June 16, 1983, granted the exemption request, 
citing the following:

    * * * because of the restricted access to this area, the 
probability of an exposure fire from the accumulation of transient 
combustibles, during normal operation, is low. We find that this 
feature, in conjunction with the one hundred feet of separation 
between redundant trains and early warning fire detection, provides 
reasonable assurance that one train will be maintained free of fire 
damage.

    NMC's letter of September 15, 2003, as supplemented February 24, 
2004, resubmitted its request for a permanent exemption from the 
requirements of Section III.G.2.b for fire area IV/fire zone 1F, 
stating the following:

    * * * in 1985, a new safe shutdown analysis crediting only the 
minimum systems and equipment required to achieve safe shutdown was 
developed. This new shutdown methodology required the use of Core 
Spray, Safety Relief Valves and Residual Heat Removal (RHR) in the 
Suppression Pool Cooling mode. Prior to that time, these systems 
were not required to achieve safe shutdown given a fire in Fire Area 
IV/Fire

[[Page 51335]]

Zone 1F. Both Division I and Division II components and cables for 
the Core Spray and Residual Heat Removal systems are contained 
within this fire area. Only one division of Safety Relief Valve 
control and indicating cables is located with this fire area. The 
impact of this revised shutdown methodology on the Fire Area IV/Fire 
Zone 1F exemption was not addressed when the shutdown model was 
revised. In addition, the Division II suppression pool temperature 
cable exit from the Torus Compartment and the location of the 
Division II suppression pool level transmitter were incorrectly 
depicted in Enclosure 2 of Reference G.2.
    * * * As a result of internal assessments of the MNGP Fire 
Protection Program, NMC determined that the existing exemption from 
10 CFR 50, Appendix R, Section III.G.2.b for the Torus Compartment * 
* * did not bound the existing plant configuration and the current 
MNGP Appendix R Safe Shutdown Analysis. The NMC has completed an 
investigation into the Torus Compartment design basis and has 
determined that an exemption is appropriate for this area.

    The results of the NRC staff's evaluation of NMC's request are 
provided below.

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 and 
safety, and are consistent with the common defense and security; and 
(2) when special circumstances are present. Special circumstances exist 
if it is not necessary to apply the technical requirements of 10 CFR 
Part 50 to achieve the underlying purpose of the regulation. The 
underlying purpose of Appendix R, Section III.G.2.b to 10 CFR Part 50 
is to assure that one train of redundant safe shutdown equipment will 
be maintained free of fire damage.
    The NRC staff analyzed the following items in the suppression pool 
torus area at MNGP to satisfy the requirements of 10 CFR 50.12 for 
granting the exemption from the automatic suppression system 
requirements of Appendix R, Section III.G.2.b:
     Minimal amount of fixed and transient combustibles
     Smoke detector provisions
     Existing separation between redundant trains of core spray 
valves, RHR cooling valves, suppression pool level transmitters, and 
the suppression pool temperature monitoring system (SPOTMOS).
    NMC's letter of September 15, 2003, stated that fixed combustibles 
consist of a single \3/4\-inch diameter radiax antenna cable, routed 
around approximately 70 percent of the perimeter wall. Other cables 
within the torus compartment are in conduit except for short runs of 
exposed cable that may exist between a device and its associated 
junction box or conduit. This amount of fixed combustibles is 
negligible. NMC also said that transient combustibles were controlled 
by procedure.
    The NRC staff sent NMC a request for additional information (RAI) 
dated January 30, 2004, asking NMC to clarify the type and quantity of 
transient combustibles it allowed into fire zone 1F. NMC's RAI response 
letter of February 24, 2004, disclosed the transient combustible 
loading for fire zone 1F. The loading consisted of two gallons of 
general-purpose solvent and three fiberglass ladders for a total of 1.7 
million British thermal units (BTUs) equating to 142 BTUs per square 
foot. NMC evaluated additional combustibles for outage pre-staging that 
have been in the fire zone and totaled them to be 2.4 million BTUs. 
This is less than 1100 BTUs per square foot. These amounts of transient 
combustibles are minimal.
    The arrangement of the core spray valves is shown on Figure 1 of 
NMC's September 15, 2003, submittal. Division 1 core spray valve MO-
1749 is located just below the ceiling of the torus compartment near 
column lines N and 8.9. Division 2 core spray valve MO-1750 is located 
in the same compartment near column lines N and 3.1. Approximately 130 
feet separate these valves and their associated cables. The drywell 
also blocks the direct line-of-sight. Smoke detectors, that are 
annunciated in the control room, are near each core spray valve with 
three more detectors intervening on each of the two paths around the 
torus compartment.
    The arrangement of the RHR cooling valves is also shown on Figure 1 
of NMC's submittal. Division 1 RHR cooling valves MO-2006 and MO-2008 
are located in the torus compartment between column lines N and P and 
7.9. Division 2 RHR cooling valve MO-2009 is located in the same 
compartment between column lines N and P and 4.1 and 5.1. Approximately 
130 feet separate the Division 1 valves and their associated cables 
from the Division 2 valves. The drywell also blocks the direct line-of-
sight. Smoke detectors, that are annunciated in the control room, are 
near each RHR cooling valve with three more detectors intervening on 
each of the two paths around the torus compartment.
    As previously discussed in Section 2.0 of this evaluation, the 
NRC's letter of June 16, 1983, granted an exemption for the suppression 
pool level transmitters. However, during the NRC staff's evaluation of 
NMC's September 15, 2003, exemption request, the staff identified 
discrepancies between Figures 1 and 2 concerning the routing of conduit 
for Division 1 and Division 2 suppression pool level transmitters 
LT7338A and LT338B. The NRC's RAI of January 30, 2004, questioned the 
location of the conduit and the associated penetrations exiting the 
fire zone. NMC's RAI response corrected the location and placed all of 
the information on Figure 2 of the revised submittal. Division 1 and 
Division 2 components are separated by at least 75 feet. Smoke 
detectors that are annunciated in the control room are near each level 
transmitter, with additional detectors intervening between the 
divisions in the torus compartment.
    The SPOTMOS at MNGP consists of two redundant divisions. Each of 
the divisions has eight resistance temperature detectors (RTDs). 
Cabling inside conduit connects the RTDs in each division, runs around 
the suppression pool in close proximity to each other, and then exits 
the fire zones at least 75 feet apart. NMC's letter of September 15, 
2003, stated that the system could operate in an ``operable but 
degraded'' mode to support post-fire safe shutdown with as little as 
one detector in one train being operable.
    Due to the close proximity of the conduits, and the concern that a 
single fire could involve both Division 1 and Division 2 conduits, the 
NRC staff requested further information on the SPOTMOS in its RAI. 
Specifically, the NRC staff requested NMC to address how the SPOTMOS 
would automatically eliminate (1) a failed temperature sensor, and (2) 
a fire-induced failure (hot short, short to ground, open, or increased/
decreased resistance or voltage) of the cable to the temperature 
elements that is inside conduit. NMC's RAI response of February 24, 
2004, described the operation of the system, addressing each of the 
failure modes. The critical distance between Division 1 and Division 2 
for operation in the operable-but-degraded mode is at least 85 feet 
(where the cables enter the torus compartment). Smoke detectors, that 
annunciate in the control room, are located near each cable entry. 
Additional smoke detectors are distributed throughout the torus 
compartment.
    The NRC staff concludes that NMC has met the underlying purpose of 
Appendix R, Section III.G.2.b, without having an automatic fire 
suppression system in the suppression pool torus area at MNGP 
considering the following:

[[Page 51336]]

     Minimal amount of fixed and transient combustibles present
     Smoke detector provisions
     Separation between redundant trains of core spray valves, 
RHR cooling valves, and suppression pool level transmitters
     Ability of SPOTMOS to continue to operate with at least 
one RTD on one train in the operable-but-degraded mode for any fire in 
fire zone 1F that involved both conduit trains
    The NRC staff further concludes that pursuant to 10 CFR 
50.12(a)(2)(ii), application of the regulation in these particular 
circumstances is not necessary to achieve the underlying purpose of the 
rule. Therefore, NMC's exemption request is acceptable.

4.0 Conclusion

    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. Also, special circumstances are present. 
Therefore, the Commission hereby grants NMC a permanent exemption from 
the requirements of 10 CFR Part 50, Appendix R, Section III.G.2.b, to 
not provide an automatic fire suppression system for fire area IV/fire 
zone 1F at MNGP.
    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 (69 FR 46187).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 6th day of August 2004.

    For the Nuclear Regulatory Commission.
Ledyard B. Marsh,
Director, Division of Licensing Project Management, Office of Nuclear 
Reactor Regulation.
[FR Doc. 04-18885 Filed 8-17-04; 8:45 am]
BILLING CODE 7590-01-P