Southern Nuclear Operating Company, Joseph M. Farley Nuclear Power Plant, Units 1 and 2; Exemption, 49324-49331 [E5-4597]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 70, Number 162 (Tuesday, August 23, 2005)]
[Notices]
[Pages 49324-49331]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E5-4597]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-348 and 50-364]


Southern Nuclear Operating Company, Joseph M. Farley Nuclear 
Power Plant, Units 1 and 2; Exemption

1.0 Background

    The Southern Nuclear Operating Company (SNC, the licensee) is the 
holder of Renewed Facility Operating License Nos. NPF-2 and NPF-8 which 
authorizes operation of Joseph M. Farley Nuclear Power Plant (FNP), 
Units 1 and 2. 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 two pressurized-water reactors located in 
Houston County, Alabama.

2.0 Request/Action

    Title 10 of the Code of Federal Regulations (10 CFR) Part 50, 
Section 50.48, ``Fire Protection,'' requires that each operating 
nuclear power plant have a fire protection plan that satisfies General 
Design Criterion (GDC) 3, ``Fire Protection,'' of appendix A to part 
50. Section 50.48(b) also references Appendix R, ``Fire Protection 
Program for Nuclear Power Facilities Operating Prior to January 1, 
1979,'' to part 50, which establishes fire protection features required 
to satisfy GDC 3 with respect to certain generic issues for nuclear 
power plants licensed to operate before January 1, 1979. On December 
29, 1986, the NRC staff granted SNC Exemption Request 1-3, ``Service 
Water Intake Structure--Fire Area 72,'' from certain requirements of 
Appendix R, Section III.G.2.c that requires fire detection and fire 
suppression capabilities and the enclosure of cables, equipment and 
associated non-safety circuits of one redundant train of safe shutdown 
equipment in a one-hour rated fire barrier. The Exemption issued on 
December 29, 1986, listed a total of ten items specific to Fire Area 72 
that were part of Exemption Request 1-3. Exemption Request 1-3 was 
included in SNC's request, dated March 13, 1985, as supplemented, and 
is applicable to Fire Area 72 for the Service Water Intake Structure 
(SWIS) which is common to FNP, Units 1 and 2.
    By letters dated August 28, 2003, December 28, 2004, and June 9, 
2005, SNC submitted a proposed revision to Exemption Request 1-3. SNC 
stated in its August 28, 2003, letter that the proposed revisions to 
Exemption Request 1-3 would clarify FNP's fire protection licensing 
basis, delete unnecessary attributes of the prior approved exemption, 
and revise the remaining prior exemption attributes to remove 
references to one-hour Kaowool fire barrier material. SNC also stated 
that the proposed revision to Exemption Request 1-3 is part of SNC's 
comprehensive plan to respond to concerns about Kaowool fire barrier 
material. SNC's August 28, 2003, letter re-listed the Exemption Request 
1-3 items and numbered them as 1 through 9 and ``Addendum to Request'' 
for ease of reference. The August 28, 2003, letter also added an item 
designated as ``Other'' that was not explicitly addressed in the 
December 29, 1986, NRC Safety Evaluation. Therefore, a total of 11 
items (1 through 9, ``Addendum to Request'', and ``Other'') comprise 
the revised exemption request in SNC's August 28, 2003, letter.

3.0 Discussion

    Pursuant to 10 CFR 50.12, ``Specific Exemptions,'' 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(a)(2)(ii), in that the application of these regulations in this 
circumstance is not necessary to achieve the underlying purpose of the 
regulations.
    The underlying purpose of Appendix R, Section III.G, ``Fire 
protection of safe shutdown capability,'' 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

[[Page 49325]]

station(s) can be repaired within 72 hours.
    In SNC's letter dated August 28, 2003, SNC stated that they 
recognize FNP, Unit 1 was licensed to operate prior to January 1, 1979, 
is subject to Appendix R to 10 CFR Part 50 and requires an exemption 
for any deviation to the rule, but that FNP, Unit 2 was licensed to 
operate after January 1, 1979, and would require a deviation from any 
commitment to comply with the rule. SNC stated that they did not 
distinguish between an exemption request and deviation request (license 
amendment) in their August 28, 2003, letter for the two units because 
the subject matter of the original Exemption Request 1-3 and this 
revised exemption is located in an area of the plant that services both 
units, and because the original Exemption Request 1-3 did not 
separately provide for a deviation (license amendment).

Overview of Approach Used by Licensee

    For this specific fire protection application, SNC proposes plant 
and fire protection program modifications under FNP's current license 
conditions, and has performed deterministic re-analyses and a risk-
informed, performance-based evaluation to revise existing Exemption 
Request 1-3 for the SWIS Fire Area 72.
    The changes proposed by SNC to Exemption Request 1-3 will (1) 
Remove some conditions in the 1986 Exemption Request 1-3; (2) eliminate 
some manual actions; (3) define new fire areas; (4) modify the success 
criterion for the ability to remove decay heat and safely shutdown in 
the event of a fire in the SWIS; and (5) remove reliance on FNP, Unit 1 
lube and cooling water pumps associated with the service water pumps.
    As reflected in 10 CFR 50.48(c), the NRC has adopted National Fire 
Protection Association Standard 805, 2001 Edition (NFPA 805), with a 
few exceptions, as a risk-informed, performance-based alternative to 
NRC fire protection requirements in 10 CFR 50.48(b) and as an optional 
new licensing basis for plants licensed after 1979. Licensees who 
propose to maintain a complete fire protection program that complies 
with 10 CFR 50.48(c) as an alternative to 10 CFR 50.40(b) must complete 
their implementation of the methodology outlined in NFPA 805 for the 
entire plant and submit a application for a license amendment in 
accordance with the regulations. Although SNC has not proposed to 
revise its complete FNP fire protection program in accordance with 10 
CFR 50.48(c) and NFPA 805, SNC has used the methodology of NFPA 805 for 
certain specific issues in its proposed revision to Exemption Request 
1-3, as discussed below. The NRC had also previously issued Regulatory 
Guide (RG) 1.174 (Revision 1), ``An Approach for Using Probabilistic 
Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to 
the Licensing Basis''. SNC has used risk-informed, performance-based 
analysis tools and has used RG 1.174 for the risk acceptance criteria.
    In general, SNC conducted a review of the SWIS which included 
deterministic re-analyses and an analysis using the risk-informed, 
performance-based methods. SNC concluded that the review and analysis 
showed that some of the conditions in existing Exemption Request 1-3 
were unnecessary, that the licensee would no longer rely upon some 
conditions in the exemption by upgrading a dividing wall and defining 
new fire areas, by modifying lubrication and cooling support for 
Service Water pumps and other program changes, and that, by plant 
modifications and re-analysis, show that by performing the above 
modifications, removal of the reliance on Kaowool would maintain or 
enhance safety while reducing unnecessary regulatory burden. The review 
and analysis conducted by SNC reflected a combination of planned 
modifications to FNP, deterministic re-analyses, and combined risk-
informed and fire modeling analyses.

Area Description

    The SWIS structure is located outside of the nuclear main power 
block and its support buildings. It is common to FNP, Units 1 and 2 and 
contains cables, pumps, valves, and other equipment necessary for the 
service water system. The SWIS supplies cooling water from the Service 
Water pond to the various essential components in both the nuclear main 
power block and balance of plant systems which require heat removal for 
proper operation during normal and accident conditions including the 
cooling certain plant equipment needed to achieve and maintain safe 
shutdown in the event of a fire. Each reactor unit has five pumps, two 
each in redundant Trains A and B, and a swing pump that can be aligned 
to either train. These pumps are spaced between five and six feet 
apart, on centers, and are protected by automatic fire suppression and 
detection systems. Redundant Train A and Train B cables supply power 
and controls to the pumps and support equipment. These cables are in 
close proximity where they enter the SWIS in the northeast corner of 
the building. Motor operated valves located in the strainer pit direct 
the pump flow for Trains A and B. These valves are horizontally 
separated 6 feet 6 inches on center on the FNP, Unit 1 side and 5 feet 
on center on the FNP, Unit 2 side of the strainer pit.
    In its letter dated August 28, 2003, SNC stated that power cables 
in the SWIS are contained in conduit and all cables in the SWIS are 
qualified to the Institute of Electrical and Electronics Engineers 
(IEEE) 383 standard. In its letter dated December 28, 2004, SNC further 
stated that power and control cables have jacket and insulation 
materials that are qualified to the IEEE-383 standard and utilize 
thermoset materials. SNC stated that nearly all cables in the SWIS have 
thermoset plastic jacket and insulation material. SNC identified eight 
low-voltage polyvinyl chloride (PVC) PVC/PVC cables in a tray along the 
north and west wall that are thermoplastic. These cables are not 
located in trays and SNC stated that portions of the cable will be 
removed to meet the fire model analysis.
    SNC will upgrade the nominal 18 inch concrete wall between Fire 
Zone 72A and Fire Zones 72B, C, D and E to meet the requirements of 
FNP's Fire Protection Program for a minimum 3-hour fire area boundary. 
The upgrade to the wall includes sealing penetrations and replacing un-
rated doors with 3-hour rated fire doors. Three new fire areas will be 
defined, 72A, 72B/72C and 72D/72E. These changes will improve fire 
safety and defense-in-depth by reducing potential fire propagation 
paths between the pump deck and switchgear rooms, as well as between 
redundant switchgear rooms.
    Fire Areas 73 and 74 remain unchanged with respect to this 
exemption request revision. On the FNP, Unit 1 side of the SWIS pump 
deck, floor curbs are located between the B- and C-Pumps and the C- and 
D-Pumps. SNC will provide a new floor curb to be located between the 
FNP, Unit 1 E-Pump and the east wall of the SWIS. On the FNP, Unit 2 
side of the SWIS pump deck, floor curbs are located between the B- and 
C-Pumps and the C- and D-Pumps. These floor curbs and the slope of the 
floor help to confine a lubricant spill from one of the Service Water 
pumps and limit fire damage to adjacent pumps.
    A concrete wall from floor to ceiling is located between the FNP, 
Unit 1 and FNP, Unit 2 Service Water pumps at the pump deck level. 
Radiant heat shields are provided on each side of the FNP, Unit 1 and 
FNP, Unit 2 swing Service Water pumps (C-Pump) to provide radiant heat 
shielding to and from adjacent Service Water pumps.

[[Page 49326]]

Fire Protection Equipment

    The SWIS is provided with an area-wide smoke detection system 
located in all areas of the SWIS including the pump motor area, under 
the pump motor deck, in the battery rooms, in the stairways, and in the 
strainer area. The smoke detection system provides a local alarm and 
annunciates in the control room. In addition, activation of any smoke 
detector trips the clappers for all three preaction sprinkler systems. 
Tripping the clappers charges the preaction sprinkler systems with fire 
water.
    The SWIS is also protected by automatic preaction sprinkler 
systems. Two preaction systems provide coverage to the entire pump 
deck, the area in the strainer pit beneath the pump deck, and to 
safety-related cabling in the upper northeast corner of the Service 
Water pump room. In addition, a third preaction 'spray' system for 
local application protects the Service Water pumps. Local carbon 
dioxide fire suppression systems are provided in the switchgear and 
transfer switch panels in Fire Zones 72B, 72C, 72D and 72E.
    Upon receipt of an alarm, the Control Room would dispatch the Fire 
Brigade to the SWIS. Manual fire fighting equipment consisting of hose 
stations and portable fire extinguishers is available inside the SWIS. 
In addition, two fire hose/hydrant houses are located directly outside 
of the SWIS within the security fence. Therefore, all areas of the SWIS 
can be reached with an effective hose stream.
    Operability and surveillance requirements for fire protection 
systems, including those provided for the SWIS are provided by the FNP 
Final Safety Analysis Report . The operability of the SWIS fire 
protection systems will continue to ensure defense-in-depth is 
maintained.

Combustible Controls

    Processes and procedures are in place at FNP to address 
housekeeping and control of combustible loading throughout the plant. 
This includes housekeeping and combustible loading control in the SWIS. 
The procedures provide guidance for bringing combustibles into a fire 
area for any plant activity including guidance for determining the 
amount and type of fire extinguishing equipment in the event of 
temporary increases in potential fire loading.
    SNC will implement additional specific transient combustible 
controls to restrict transient combustibles from being stored/located 
in the northeast corner and in the vicinity of the Service Water pumps. 
Configuration control will be maintained (from a fire protection 
program perspective) over the type and quantity of lubrication oil used 
in the Service Water pump motors. SNC will implement precautions to 
limit the amount of lubricant in the vicinity of the Service Water 
pumps during lubricant changes by removing the drained lubricant from 
the area prior to bringing the new (unused) lubricant into the area.
    This will provide additional assurance that the conditions of the 
risk-informed, performance based evaluation are met and that defense-
in-depth is maintained in the area.

Fire Modeling

    SNC's evaluation uses the concepts from NFPA 805 for fire modeling. 
NFPA 805 presents two concepts, the maximum expected fire scenario 
(MEFS) and limiting fire scenario (LFS). The MEFSs or worst case 
credible scenarios are identified by considering the fire types that 
have a reasonable likelihood of occurrence. The LFSs are developed by 
altering one or more input parameters to MEFSs to determine the 
threshold at which a target would exceed the critical temperature or 
radiant heat flux. The purpose of determining an LFS was to perform a 
sensitivity analysis and demonstrate adequate margin between parameters 
when determining MEFS and LFS.
    Three scenarios were evaluated by the licensee, (1) transient 
combustible material fire in the northeast corner of the SWIS, (2) FNP, 
Unit 1 Service Water pump fire, and (3) FNP, Unit 2 Service Water pump 
fire. These scenarios were chosen since they were believed to be the 
most likely to affect multiple trains of systems. Consolidated Model of 
Fire Growth and Smoke Transport (CFAST) (Peacock et al., 2004), HEATING 
Version 7.3 (Childs, 1998), and empirical correlations (thermal plume 
and radiant heat flux) were used to model the fires. The hot gas layer 
temperature and radiant heat flux exposure to the safety-related cable 
trays and junction boxes were determined for the MEFSs. The licensee 
evaluated other fire scenarios such as smaller quantities of lubricant 
oil, motor windings, and other cable trays and concluded that the MEFS 
for these fire scenarios would not have resulted in target damage.
    The preaction sprinkler system actuation was evaluated for each 
fire scenario although sprinkler actuation was not directly credited in 
the fire modeling analysis except for defense-in-depth considerations.
    In Scenario 1, transient combustible material fire in the northeast 
corner of the SWIS (Item 4 and Item ``Other'' of the revised Exemption 
Request 1-3), CFAST was used to calculate the maximum hot gas layer 
temperature and layer height above the floor. Localized target exposure 
temperatures to cable tray targets (Train A and Train B cables in the 
northeast corner) were calculated using thermal plume correlations. 
This simulation assumed there was no Kaowool fire barrier protecting 
the Train A or B cable trays. The results of the CFAST fire simulation 
for an MEFS indicate that the maximum hot gas layer temperature would 
be below the cable damage temperature and that there would be no 
significant radiant exposure to targets located in the SWIS. Based on 
the fire modeling results, SNC concluded that the modeled SWIS targets 
would not be adversely impacted by an MEFS.
    In Scenario 2, FNP, Unit 1 pump fire scenario (Item 9 of the 
revised Exemption Request 1-3), the effects of a lubricant oil pool 
fire, located between the FNP, Unit 1 Service Water pumps and the south 
wall of the SWIS were modeled. CFAST was used to calculate the maximum 
hot gas layer temperature and layer height above the floor, and thermal 
radiation heat transfer correlations were used to calculate target 
exposure to radiant heat flux. The targets evaluated in this scenario 
are cable trays (Train-A), using hot gas layer information from CFAST 
and pump motor junction boxes using thermal radiation from the heat 
transfer correlations. The results of the CFAST fire simulation 
indicate that the local targets on the Pump Deck would be immersed by 
the hot gas layer. However, the calculated hot gas layer temperature is 
lower than the damage temperature of the cable. The radiation heat 
transfer calculation shows that the fire originating from a lubricating 
oil spill could cause the incident heat flux at a second tier pump 
(i.e., pump adjacent to the pump where the spill occurs) or the Train A 
cable trays along the east wall to exceed critical heat flux levels; 
however, the duration of the fire is not sufficient for the flux to 
cause the target surface temperature to exceed the critical cable 
temperature based on the analysis using the HEATING7 model. Therefore, 
based on this analysis at least one Service Water pump would not be 
adversely impacted by this fire scenario.
    In Scenario 3, FNP, Unit 2 pump fire scenario (Item 9 of the 
revised Exemption Request 1-3), the effects of a lubricant oil pool 
fire, located between the FNP, Unit 2 Service Water pumps and the south 
wall of the SWIS were modeled. The targets evaluated in this scenario 
are pump motor junction

[[Page 49327]]

boxes. There are no cable tray targets modeled in this fire scenario. 
Scenario 3 is bounded by Scenario 2 because the pumps on FNP, Unit 2 
contain less oil and would define a fire of shorter duration than in 
Scenario 2. Therefore, based on this analysis at least one Service 
Water pump would not be adversely impacted by this fire scenario.
    A sensitivity analysis was performed for Scenarios 1, 2, and 3 to 
demonstrate the sensitivity of the results of the calculations to 
variations in the MEFSs input parameters. The sensitivity analysis of 
the results to the assumptions regarding the composition of the 
transient fuel package and the impact of ventilation conditions in the 
SWIS was examined. The results clarify the degree of conservatism 
inherent in the calculation and the margin between the MEFS and the 
LFS. The calculations were compared over a parameter spread that 
included conditions that would result in failure of the target. The 
licensee concluded that the sensitivity analysis demonstrates that the 
results and conclusions would not change with the exception of adjacent 
pump motor junction box targets. As a result, these targets are assumed 
to fail in the analysis.

Risk Assessment

    RG 1.174 specifies that the risk associated with a plant change be 
determined by considering the change in Core Damage Frequency (CDF) and 
Large Early Release Frequency (LERF) that result from the plant change. 
These changes in CDF and LERF are calculated by comparing the CDF and 
LERF values for the pre- and post-change locations within the fire area 
that will be affected by the change to ensure that all contributors to 
risk are included. Thus, the fire risk analysis focused only on 
elements of the SWIS that had been or were proposed to be changed from 
SNC's current licensing basis. These elements were associated with 
pump/motor lubricant fires (one for each pump or ten cases in all).
    The FNP plant-specific Level 1 and Level 2 Probabilistic Risk 
Assessment (PRA) Model was used, with modifications, to evaluate the 
impacts on plant risk of postulated fires originating in the SWIS. The 
modifications involved two changes that are summarized below. The 
analysis did not add any fire specific operator actions or recoveries 
to the base plant PRA Model.
    The scope of analyses that were performed by SNC for the changes to 
Exemption Request 1-3 included a re-analysis of the service water 
system performance. SNC's re-analysis concluded that a single service 
water pump per unit was sufficient to satisfy the system performance 
requirements for fire protection safe shutdown. The re-analysis results 
were incorporated into the PRA Model by lowering the number of Service 
Water pumps per train required for system success from two to one. The 
total plant CDF from internal events that is reported below reflects 
this change in the success criterion.
    The licensee modified the plant PRA model to take advantage of 
recent vendor data related to reactor coolant pump (RCP) seal 
performance. The specific data is related to seal performance given 
loss of motor bearing cooling. The licensee stated their model assumed 
increased seal leakage will begin at 15 minutes after loss of all RCP 
seal cooling based on information in WCAP-16141, ``RCP Seal Leakage PRA 
Model Implementation Guidelines for Westinghouse PWRs'' and that they 
credit recovery of RCP seal injection using the standby train of 
Component Cooling Water and charging through operator action done by 
procedures and performed from the main control room. Leakage due to 
loss of motor bearing cooling is an additional contribution to CDF with 
respect to the RCP seal loss-of-coolant accident (LOCA) PRA model. When 
these two leakage models are combined, the resultant CDF contribution 
slightly exceeds that from an equivalent application via the Rhodes RCP 
seal LOCA model, i.e., it is conservative. The total plant CDF from 
internal events that is reported below reflects this change in the 
success criterion.
    The performance of the PRA quantifications with the changes 
described above applied the same techniques and processes as used for 
the Fire IPEEE. This basically involved the setting of certain model 
basic events to ``TRUE'' by translating the fire modeling results for 
the MEFS into plant equipment damage states. SNC developed a fire 
ignition frequency for each fire scenario by partitioning the generic 
fire frequencies from the Electric Power Research Institute Fire Events 
Database. The resulting CDF for each of the fire scenarios was 
aggregated to obtain the cumulative risk for the proposed change. A 
separate calculation for the ``baseline'' CDF was not developed. 
Instead, the CDF for the changed configuration was taken as a 
conservative surrogate for the increase in risk.
    The total plant CDF from internal events for FNP, Unit 1 and 2 is 
3.86E-05/yr and 5.81E-05/yr, respectively based on one Service Water 
pump as the success criterion. A comparison of the Fire IPEEE results 
with the internal events PRA results that were applicable at that time 
shows that the FNP, Unit 1 Fire CDF was approximately 20 percent higher 
than the corresponding FNP, Unit 1 internal events CDF. This would 
result in an estimated total plant risk of 8.5E-05/yr.
    The FNP, Unit 2 Fire CDF was approximately 10 percent less than the 
corresponding Unit 2 internal events CDF. This would result in an 
estimated total plant risk for FNP, Unit 2 of 1.1E-04/yr.
    The CDF and LERF for the changed configuration was taken as a 
conservative surrogate for the increase in risk, i.e. the baseline CDF 
and LERF was assumed to be zero such that delta CDF and LERF was 
conservatively estimated as the total CDF and total LERF for the 
changed contribution (no subtraction of baseline value). As a result, 
the licensee's risk analysis determined that a conservative estimate of 
the CDF associated with the ten cases would be approximately 6.5E-07/yr 
per unit. The licensee reports that the CDF for the cases ranged from 
2.08E-08/yr per unit to 1.34E-07/yr per unit with no one case 
dominating as a contributor relative to the rest. Based on the estimate 
for total CDF, this places the proposed change in Region III of the RG 
1.174 acceptance criteria for CDF.
    In order to gain further insights, the fire areas that were the 
dominant contributors to risk from the Fire IPEEE were requantified 
using the current plant PRA model. This re-quantification of dominant 
fire areas provided a cumulative CDF of 4.98E-05/yr and 5.87E-05/yr for 
FNP, Units 1 and 2, respectively. Using these updated values, the 
estimated total plant risk for FNP, Units 1 and 2 is 8.84E-05/yr and 
1.17E-04/yr, respectively.
    The licensee stated that the contribution to LERF from a SWIS fire 
is the result of core damage combined with failure of containment 
isolation. The conditional probability of containment isolation failure 
(crediting only check valves and fail closed air-operated valves) is 
2.13E-4. The licensee stated that this resulted in a total LERF 
contribution from the seven SWIS fire scenarios analyzed for FNP, Unit 
1 of 1.38E-10/yr per unit. This indicates the same LERF for FNP, Unit 2 
since both units have the same CDF. SNC concluded that the LERF 
associated with the proposed change is negligible given the acceptance 
criteria of RG 1.174. RG 1.174, Section 2 also requires consideration 
of five key principles that the change is expected to

[[Page 49328]]

meet. SNC concluded that all of the five principles have been met.

Defense-in-Depth

    10 CFR Part 50, Appendix R, section II states that a licensee's 
fire protection program extend the concept of defense-in-depth to fire 
protection with the following objectives:
    I. To prevent fires from starting,
    II. To detect rapidly, control, and extinguish promptly those fires 
that do occur, and
    III. 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.
    RG1.174 also identifies factors to be considered when evaluating 
defense-in-depth for a risk-informed change.
    SNC has evaluated defense-in-depth and stated the following:
    Fire prevention is strengthened by SNC's commitment to enhance the 
transient combustible control program in the SWIS northeast corner and 
in the vicinity of the Service Water pumps.
    SNC proposes no changes to the existing fire detection and 
automatic fire suppression systems in the SWIS and will continue to 
control these systems to maintain defense-in-depth. Protection for 
structures, systems and components is weakened by the elimination of 
the reliance on the Kaowool fire barrier in the northeast corner of the 
SWIS and the strainer pit. However, the elimination of the reliance on 
Kaowool has been evaluated by SNC in accordance with RG 1.174 or by 
deterministic re-analysis. Protection for structures, systems and 
components is strengthened by reducing the population of equipment 
requiring protection due to deterministic re-analyses (i.e., single 
Service Water pump and motor operated valve circuit analysis) and plant 
modifications (FNP, Unit 2 elimination of lube and cooling pumps); and 
by modifying the existing barriers between the pump deck and switchgear 
rooms and between disconnect switch rooms to 3-hour fire rated 
barriers; and by installing a floor curb on the FNP, Unit 1 side of the 
pump deck to limit fire exposure to the Train A cables along the east 
wall.

Safety Margins

    RG 1.174 provides acceptable guidelines to ensure sufficient safety 
margins are maintained. RG 1.174 states that the proposed change 
provide sufficient margin to account for analysis and data uncertainty. 
The licensee concluded that for Scenario 1, a heat release rate to four 
times that modeled in the MEFS is needed to reach the LFS; for Scenario 
2 an increase in combustible oil lubricant volume of 75 percent for a 
C-pump fire scenario and an increase four times the volume of 
combustible oil lubricant for an A-,B-,D-or E-pump fire scenario are 
needed to reach the LFS; and for Scenario 3 a minimum increase five 
times the volume of combustible oil lubricant to reach the LFS.
    SNC addressed uncertainty for Exemption Request 1-3, Item 9 and 
Item ``Other'' by considering the degree to which the fire models/
calculations used bound the uncertainty in the input parameters. The 
licensee conducted an evaluation on the input parameters and concluded 
that the models/calculations that were used bounded the uncertainty 
except for the limiting oxygen index (LOI) parameter. However, the 
licensee concluded that the LOI assumption below a certain threshold is 
not possible for the temperatures predicted and is therefore not 
credible.
    Uncertainty was further addressed by determining an LFS for each 
fire scenario. The LFS was determined by increasing one or more of the 
parameters that characterize the fire used for the MEFS until a failure 
condition is attained.
    A sensitivity analysis was also conducted to determine that the 
conclusions would not be altered. In the case of the SWIS fire 
scenarios, sensitivity was conducted on the natural and forced 
ventilation conditions, the composition of the transient Class A fuel 
package (for Scenario 1) and the absorptance of the targets. As a 
result of the sensitivity analysis, SNC determined that some adjacent 
pump motor targets could be heated to the critical temperature. SNC 
then conservatively concluded that these targets would fail despite the 
results of the MEFS to the contrary. SNC concluded that other targets 
were not affected.

Evaluation of Exemption Request 1-3 Items

    The NRC staff examined the licensee's submittals to determine if 
the revised Exemption Request 1-3 in Fire Area 72 of the SWIS would 
meet the underlying purpose of the 10 CFR part 50, appendix R rule.
    The NRC staff has evaluated each of the revised items of Exemption 
Request 1-3 on a case by case basis by ensuring adherence to the fire 
modeling approach discussed in NFPA 805, ensuring that RG 1.174 
criteria are met, assessing that a reasonable balance among the 
elements of defense-in-depth is maintained, and ensuring safety margins 
are maintained, where appropriate.
Item 1
    SNC proposes to implement modifications to each of the five FNP, 
Unit 2 service water pumps by December 2006 that will result in 
removing the need for the redundant lubricating oil and coolant pumps, 
valves and control stations for FNP, Unit 2. The licensee concluded 
that modifications will eliminate the need to consider fire-induced 
impacts from a fire on the FNP, Unit 2 lubricating oil and coolant 
pumps, valves and their control stations as well as removing these 
pumps as ignition sources and combustible loadings. Based on the plant 
modifications, SNC concluded that the conditions of Exemption Request 
1-3, Item 1 will no longer be applicable following completion of those 
plant modifications. On these bases, the NRC staff concludes that, upon 
completion of the modifications to the pumps as discussed above, there 
will be no further need for the exemption provided in the first 
paragraph of Section 2.3 of the NRC staff's December 29, 1986, 
exemption and, accordingly, it would be deleted.
Item 2: FNP, Unit 2 Side of Strainer Pit
    For the strainer inlet valves and swing pump discharge valves in 
the FNP, Unit 2 side of the strainer pit, SNC stated in its December 
28, 2004, response to question 26 and in its June 9, 2005, response to 
question 2, that it had performed a deterministic re-analysis on the 
cables for these valves. SNC's review of the circuitry located in the 
strainer pit determined that spurious operation of the valves could not 
result if the power cables to the valve motors and control cables to 
the valve position switches were subjected to hot shorts, open 
circuits, or shorts to ground. SNC stated that power is removed during 
normal operation from swing service water pump discharge valves 
Q2P16V507-A and Q2P16V506-B and that spurious operation of the valves 
due to a 3-phase hot short does not require evaluation in accordance 
with the guidance in Generic Letter 86-10, Section 5.3.1. SNC stated 
that the main and control power to strainer inlet valves Q2P16V511-A 
and Q2P16V508-B is not isolated during normal operation and that open 
circuits or short circuits will not result in spurious operation of the 
valves and that a 3-phase hot short does not require evaluation in 
accordance with the guidance in Generic Letter 86-10, Section 5.3.1. 
The licensee further states that for the control cables to limit 
switches, hot shorts, open circuits or shorts to ground could not 
result in

[[Page 49329]]

spurious operation because the cables do not contain the conductors 
necessary to energize the motor starters due to open control room 
switch contacts. Based on SNC's analysis, SNC concluded that reliance 
on Kaowool as part of the basis for Exemption Request 1-3, Item 2 is no 
longer necessary. The NRC staff concludes that on the basis of SNC's 
deterministic-based findings that the valves will not be repositioned 
due to a fire, the fire detection and suppression features for Fire 
Area 72A and the defense-in-depth measures as discussed above, that a 
continued exemption from the requirements of appendix R, section 
III.G.2.c for this item is acceptable.
Item 3: FNP, Unit 1 side of strainer pit
    For the strainer inlet valves and swing pump discharge valves in 
the FNP, Unit 1 side of the strainer pit, SNC stated in its December 
28, 2004, response to question 26 and in its June 9, 2005, response to 
question 2, that it had performed a deterministic re-analysis on the 
cables for these valves. SNC's review of the circuitry located in the 
strainer pit determined that spurious operation of the valves could not 
result if the power cables to the valve motors and control cables to 
the valve position switches were subjected to hot shorts, open 
circuits, or shorts to ground. SNC stated that power is removed during 
normal operation from swing service water pump discharge valves 
Q1P16V507-A and Q1P16V506-B and that spurious operation of the valves 
due to a 3-phase hot short does not require evaluation in accordance 
with the guidance in Generic Letter 86-10, Section 5.3.1. SNC stated 
that the main and control power to strainer inlet valves Q1P16V511-A 
and Q1P16V508-B is not isolated during normal operation and that open 
circuits or short circuits will not result in spurious operation of the 
valves and that a 3-phase hot short does not require evaluation in 
accordance with the guidance in Generic Letter 86-10, Section 5.3.1. 
The licensee further states that for the control cables to limit 
switches, hot shorts, open circuits or shorts to ground could not 
result in spurious operation because the cables do not contain the 
conductors necessary to energize the motor starters due to open control 
room switch contacts. Based on SNC's analysis, SNC concluded that 
reliance on Kaowool as part of the basis for Exemption Request 1-3, 
Item 3 is no longer necessary. The NRC staff concludes that on the 
basis of SNC's deterministic-based findings that the valves will not be 
repositioned due to a fire, the fire detection and suppression features 
for Fire Area 72A and the defense-in-depth measures as discussed above, 
that a continued exemption from the requirements of Appendix R, Section 
III.G.2.c for this item is acceptable.
Item 4: Discharge Valves to Wet Pit and Storage Pond Flume
    For Fire Zone 72A, SNC performed a deterministic re-analysis on the 
redundant safe shutdown service water Train A and Train B cables, 
associated with service water discharge to the wet pit and storage pond 
flume, shared by Unit 1 and Unit 2. The December 29, 1986, exemption, 
page 11, first paragraph, reflected SNC's original finding that there 
was a potential for these valves to be mis-positioned by fire effects 
and that this could be acceptably dealt with by manually realigning the 
valves, if needed, within a required 24-hour period. SNC's submittals, 
specifically its June 9, 2005, submittal states that the main and 
control power to valves QSP16V505-A, QSP16V507-A, QSP16V506-B and 
QSP16V508-B is not isolated during normal operation and that open 
circuits or short circuits will not result in spurious operation of the 
valves and that a 3-phase hot short does not require evaluation in 
accordance with the guidance in Generic Letter 86-10, Section 5.3.1. 
SNC further states that for the control cables to limit switches, hot 
shorts, open circuits or shorts to ground could not result in spurious 
operation because the cables do not contain the conductors necessary to 
energize the motor starters due to open control room switch contacts. 
For the control cables to control room switches and other interlocks, 
the licensee concluded from its deterministic analysis that hot shorts 
could result in spurious operation of the valves. However, the licensee 
used fire modeling, as discussed in the section above on the modeling 
of fire scenarios, to demonstrate that fire induced cable damage from a 
fire could not result in spurious operation of both trains of valves 
and that there would not be a need to perform the long-term manual 
operator actions previously relied upon. Based on SNC's analysis, SNC 
concluded that reliance on Kaowool as part of the basis for Exemption 
Request 1-3, Item 4 is no longer necessary. The NRC staff concludes 
that on the basis of SNC's deterministic and fire modeling analysis 
results as discussed above, the fire detection and suppression features 
for Fire Area 72, defense-in-depth measures as discussed above, and 
enhanced combustible controls, that a continued exemption from the 
requirements of appendix R, section III.G.2.c for this item is 
acceptable.
Items 5 and 6: Swing Service Water Pumps
    SNC's compliance strategy is unchanged for these two items. 
Therefore, the previous portion of the exemption issued on page 11, 
paragraphs two and three, of the December 29, 1986, exemption is 
unchanged and remains in effect. Accordingly, there is no further 
consideration in this Safety Evaluation for this item.
Item 7: Swing Service Water Pump Cables in Fire Zones 72D and 72E
    SNC states in its August 28, 2003, submittal that the current 
exemption and its bases (included on page 11, last paragraph, and page 
12, first paragraph of the December 29, 2005, exemption) remain 
unchanged because they do not involve Kaowool. The previous conditions 
for this item discussed in the NRC letter dated December 29, 1986, 
remain unchanged and there is no further consideration in this safety 
evaluation of those conditions. However, SNC has committed to implement 
plant modifications that will upgrade certain fire barriers to 3-hour 
fire ratings as previously discussed in this exemption. The creation of 
the three hour fire barriers will enhance the overall defense-in-depth 
of the SWIS.
Item 8: Swing Service Water Pump Cables in Fire Zones 72B and 72C
    SNC states in its August 28, 2003, submittal that the current 
exemption and its bases (included on page 12, second paragraph, of the 
December 29, 2005, exemption) remain unchanged because they do not 
involve Kaowool. The previous condition for this item discussed in the 
NRC letter dated December 29, 1986, remains unchanged and there is no 
further consideration in this safety evaluation of those conditions. 
However, SNC has committed to implement plant modifications that will 
upgrade certain fire barriers to 3-hour fire ratings as previously 
discussed in this exemption. The creation of the 3-hour fire barriers 
will enhance the overall defense-in-depth of the SWIS.
Item 9: Raceways for Train A Service Water Pumps
    The exemption for service water pumps that was included on page 12, 
third paragraph of the December 29, 1986, exemption was based, in part, 
on the raceways servicing the Train A service water pumps for both 
units being protected with a Kaowool blanket

[[Page 49330]]

fire barrier. SNC performed an evaluation for these raceways using a 
combined fire modeling and risk assessment analysis approach to revise 
the conditions for Exemption Request 1-3, Item 9. This approach does 
not take any credit for the Kaowool fire barrier and is addressed in 
the above Fire Modeling section discussion of scenarios 2 and 3. Based 
on SNC's Fire Modeling analysis, SNC concluded that at least one 
service water pump would not be adversely impacted by this fire 
scenario. As discussed in the above Risk Assessment section, SNC has 
also concluded that a single service water pump per unit is sufficient 
to satisfy the system performance requirements for fire protection. The 
NRC staff concludes that on the basis of SNC's deterministic and fire 
modeling analysis results as discussed above, the fire detection and 
suppression features for Fire Area 72, defense-in-depth measures as 
discussed above, and enhanced combustible controls, that a continued 
exemption from the requirements of appendix R, section III.G.2.c for 
this item is acceptable.

Addendum to Exemption Request 1-3, Fire Area 72

    SNC included an Addendum to Exemption Request 1-3 in its October 
18, 1985, submittal wherein SNC noted that adequate coordination was 
not provided between certain safe shutdown and non-safe shutdown 
circuits. The December 29, 1986, exemption noted that a design change 
had been initiated to improve breaker coordination, which would 
eliminate the concern. SNC's August 28, 2003, submittal stated that the 
design change had been completed. Accordingly, the NRC staff finds that 
the conditions requiring the exemption item that begins with the last 
paragraph of page 12 of the December 29, 1986, exemption are no longer 
present and, accordingly, this part of the exemption is no longer 
necessary.

SWIS Northeast Corner Raceways

    SNC stated in its August 23, 2003, submittal that in addition to 
the nine situations that were addressed in the exemption issued on 
December 29, 1986, that it had also considered the FNP, Units 1 and 2 
redundant Train A and Train B cables near the ceiling of the northeast 
corner of the SWIS. The northeast corner of the SWIS includes a 
``pinch-point'' where FNP, Units 1 and 2 Train A and Train B cables 
approach each other as they run along perpendicular walls from the 
corner. The cables are 20 feet above the strainer pit floor. SNC 
performed an evaluation using fire modeling as discussed in the above 
Fire Modeling section, scenario one, to support the addition of this 
condition to the exemptions for Fire Area 72. Based on the fire 
modeling results, SNC concluded that the cables would not be adversely 
impacted by an SNC's analysis to support this exemption item and SNC's 
program modifications, SNC concluded that it is unlikely the cables of 
interest would be damaged by a maximum expected fire scenario. The NRC 
staff concludes that on the basis of SNC's fire modeling analysis 
results as discussed above, the fire detection and suppression features 
for Fire Area 72, defense-in-depth measures as discussed above, and 
enhanced combustible controls, that an exemption from the requirements 
of Appendix R, Section III.G.2.c for this item is acceptable.

Modifications

    SNC will implement programmatic and design modifications as 
outlined in letters dated August 28, 2003, and December 28, 2004. These 
modifications include: (1) Modification of the FNP, Unit 2 service 
water pumps to eliminate their reliance on lubrication and cooling 
support pumps, (2) upgrading of the nominal 18-inch concrete wall 
between Fire Zone 72A and Fire Zones 72B, C, D and E to meet the 
requirements of FNP's Fire Protection Program for a minimum 3-hour fire 
area boundary. Penetrations will be sealed, un-rated doors will be 
replaced by 3-hour rated fire doors, and three new fire areas will be 
defined, 72A, 72B/72C and 72D/72E. In addition, the scope of the 
barrier surveillance program will be enhanced to ensure that the 
conditions of the risk-informed, performance-based assessment are 
maintained, (3) installation of a new floor curb on the FNP, Unit 1 
pump deck to prevent liquid spill fires associated with the FNP, Unit 1 
pumps from pooling beneath the Train A cable tray located near the east 
wall, (4) specific transient combustible controls will be implemented 
to restrict transient combustibles from being stored or located in the 
SWIS northeast corner and in the vicinity of the service water pumps. 
Configuration control will be maintained (from a fire protection 
program perspective) over the type and quantity of lubrication oil used 
in the service water pump motors. Precautions will be implemented to 
limit the amount of lubricant in the vicinity of the service water 
pumps during lubricant changes by removing the drained lubricant from 
the area prior to bringing the new (unused) lubricant into Fire Zone 
72A. Transient fuel packages associated with maintenance activities 
will be controlled via procedural changes, and (5) SNC identified eight 
low-voltage PVC/PVC cables in a tray along the north and west wall that 
are thermoplastic. SNC stated that portions of the cable will be 
removed to meet the fire model analysis.
    The evaluation that SNC prepared assesses the impact of the change. 
This evaluation uses a combination of risk-insights and deterministic 
methods to show that sufficient safety margins and defense-in-depth are 
maintained.
    The results of the risk-informed portions of the analysis are 
consistent with a change that would be acceptable when compared to the 
acceptance criteria described in RG 1.174, ``An Approach for Using 
Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-
Specific Changes to the Licensing Basis,'' Revision 1.
    The NRC staff examined SNC's rationale to support the changes to 
Exemption Request 1-3 and concludes that adequate defense in depth and 
safety margins exist and that the underlying purpose of Appendix R, 
Section III.G.2.c is met. Fire modeling demonstrates that it is 
unlikely that the cables of interest in the northeast corner will be 
damaged by a fire and that at least one service water pump for each 
unit will not be damaged by a fire. Also, fire detection and automatic 
fire suppression systems in the areas of interest remain to provide 
defense-in-depth. Based upon the above considerations, the NRC staff 
concludes that the revisions to Exemption Request 1-3 meet the 
underlying purpose of the rule. Therefore, the NRC staff concludes that 
pursuant to 10 CFR 50.12(a)(2) this exemption is acceptable.

4.0 Conclusion

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), the changes to Exemption Request 1-3 are authorized by law, 
will not present an undue risk to the public health and safety, and are 
consistent with the common defense and security. Also, special 
circumstances are present. Therefore, the Commission hereby grants SNC 
a revised exemption 1-3 from the requirements of appendix R, section 
III.G.2.c to 10 CFR Part 50 to provide 1-hour fire separation in Fire 
Area 72 for the FNP, Units 1 and 2, subject to the full implementation 
of the programmatic and plant design modifications discussed above. 
Acceptance of this revised Exemption Request 1-3 is based on the 
programmatic and plant design modifications, the deterministic re-
analyses, the risk-informed plant change evaluation and its results 
specific to the

[[Page 49331]]

SWIS, enhanced controls on transient combustibles, the existing fire 
detection and automatic fire suppression capability to maintain 
defense-in-depth, and the availability of manual fire fighting and 
associated fire fighting equipment.
    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 (70 FR 46892).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 16th day of August, 2005.

    For the Nuclear Regulatory Commission.
Ledyard B. Marsh,
Director, Division of Licensing Project Management, Office of Nuclear 
Reactor Regulation.
[FR Doc. E5-4597 Filed 8-22-05; 8:45 am]
BILLING CODE 7590-01-P