[Federal Register Volume 59, Number 2 (Tuesday, January 4, 1994)]
[Notices]
[Pages 333-335]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 93-54]


[[Page Unknown]]

[Federal Register: January 4, 1994]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-338 and 50-339]

 

Virginia Electric and Power Company (North Anna Power Station, 
Units No. 1 and No. 2)

Exemption

I
    Virginia Electric and Power Company (the licensee) is the holder of 
Facility Operating License Nos. NPF-4 and NPF-7 which authorize 
operation of North Anna Power Station, Units No. 1 and No. 2 (NA-1&2, 
the facility) at steady-state power levels not in excess of 2893 
megawatts thermal. The licenses provide, among other things, that the 
facility is subject to all the rules, regulations, and orders of the 
Nuclear Regulatory Commission (the Commission) now or hereafter in 
effect.
    The facility employs pressurized water reactors (PWRs) located at 
the licensee's site in Louisa County, Virginia.
    The licensee is implementing a refurbishment and restoration 
program for the NA-1&2 service water system (SWS). The program is being 
conducted in several stages. The subject Phase 1, Stage 4 is to be 
conducted for a period of time beginning January 3, 1994 and ending 
October 13, 1994, and will be performed during dual unit operating 
conditions. The scope of Stage 4 involves restoration of the two 24-
inch auxiliary supply lines from Lake Anna to the main SW headers. This 
consists of approximately 900 linear feet of piping (450 feet per 
line). Each 450-foot line consists of approximately 185 feet of direct 
buried piping, 230 feet of concrete-encased piping and 35 feet of 
exposed piping. To support the Phase 1, Stage 4 SWS restoration 
program, the licensee has identified one temporary exemption required 
at this time. The exemption is specified below.
II
    The Code of Federal Regulations at 10 CFR part 50, Appendix A, 
General Design Criterion-2 (GDC-2) requires that: Structures, systems, 
and components important to safety shall be designed to withstand the 
effects of natural phenomena such as * * * tornadoes, * * * without 
loss of capability to perform their safety functions.
    The licensee has requested the temporary exemption from GDC-2 
because of planned maintenance which will expose portions of the SWS 
piping to the potential effects of postulated missiles generated by 
natural phenomena. Earth and concrete protect the piping systems from 
the effects of severe weather events at the NA-1&2 site, such as 
tornadoes, for conformance with the requirements of GDC-2. The 
excavation of the auxiliary service water lines will affect only the 
missile shield protection aspects of GDC-2, with seismic qualification 
being retained. While producing a minimal increase in missile 
interaction risk, excavation of the piping does not result in total 
vulnerability to missiles. In the area of the planned excavation, the 
lines are substantially below grade and are adjacent to the turbine 
building structure. This will prevent some lateral aspects of missile 
vulnerability.
    The licensee is providing contingency measures with compensatory 
actions to provide added assurance of safe operation of the facility 
during the exemption period. Although the exemption is requested only 
for missile protection, the risk to the plant due to construction 
mishaps is more significant than the risk due to natural phenomena. 
Therefore, the compensatory measures are geared toward preventing such 
mishaps in addition to minimizing the potential for missiles generated 
by severe weather. As stated in the staff's Safety Evaluation dated 
December 27, 1993, these compensatory actions include but are not 
limited to the following:
     Electronic scanning and nondestructive locating methods 
will be used to accurately determine underground locations of piping, 
duct banks, and other buried utilities prior to excavation.
     Machine excavation will be limited to an elevation that 
does not pose a threat to the auxiliary service water (ASW) lines. The 
remaining excavation will be performed by hand operated power and 
manual tools.
     Physical barriers will be used to keep vehicles a safe 
distance from the excavation site.
     Loose materials in and around the excavation will be 
limited to only those absolutely necessary for activities in progress.
     Lifting and rigging components will be inspected and load 
tested. Lifting of equipment or construction materials over the 
excavation will be performed with adequate precautions in accordance 
with approved procedures.
     Direct verbal communication (using dedicated radios if 
necessary) will be maintained between equipment operators and 
supervisors/observers.
     Operable ASW lines will retain their seismic 
qualification.
     Engineering reviews will be performed for shoring and 
temporary supports (if required) in the excavation area.
     Gasoline powered equipment will be refilled using small 
containers and the number of containers within the excavation area will 
be restricted. This is in accordance with the existing station 
procedures.
     Worker training and shift briefings will be conducted for 
all aspects of the project.
     Severe weather procedures will be used to provide 
notification to clear the area of vehicles and loose materials in the 
event of a tornado watch or other high wind conditions.
     Adequate wind protection and heating will be provided 
during freezing weather conditions.
    Considering the existing design features and compensatory measures 
proposed by the licensee, the likelihood of damage to the exposed 
auxiliary SWS lines from postulated missiles generated by natural 
phenomena is minimal. Also, based on the compensatory measures 
provided, assurance exists that the ability to bring the plant to a 
safe shutdown will be maintained following any natural phenomena, 
including tornadoes or other severe weather which could result in 
airborne missiles. Therefore, there is reasonable assurance that the 
proposed GDC-2 exemption will present no undue risk to public health 
and safety.
III
    The Commission has determined, pursuant to 10 CFR 50.12(a), that 
special circumstances as set forth in 10 CFR 50.12(a)(2)(v). The 
exemption would provide only temporary relief from the applicable 
regulation (GDC-2). The exemption is requested for a specific time 
period after which the facility would again be in conformance with all 
the requirements of GDC-2. The licensee has made good faith efforts in 
considering alternatives to the exemption requests and has concluded 
that the Phase 1, Stage 4 SWS refurbishment and restoration program can 
only be conducted without the subject exemption during a period when 
both NA-1&2 are shut down and defueled. The impact of scheduling such a 
dual-unit outage would have significant consequences in terms of power 
supply, fuel storage, capacity, and replacement power costs. Finally, 
the exemption will indirectly result in benefits to the public from 
increased reliability of the upgraded safety-related SWS.
    Based on the above and on review of the licensee's submittal, as 
summarized in the Safety Evaluation dated December 27, 1993, the NRC 
staff concludes that the likelihood of unacceptable damage to the 
exposed auxiliary SW lines due to tornadoe-borne missiles during the 
exemption period is low.
    Based on the low probability of unacceptable events, coupled with 
the comprehensive compensatory measures which the licensee has 
committed to, the NRC staff finds the proposed exemption from GEDC-2 
acceptable.
 IV
    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12, the subject 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. The Commission further determines that 
special circumstances, as provided in 10 CFR 50.12(a)(2)(v), are 
present justifying the exemption; namely, that the exemption would 
provide only temporary relief from the applicable regulations and that 
the licensee has made good faith efforts to comply with the 
regulations.
    Therefore, the Commission hereby approves the following exemption: 
NA-1&2 may operate without conforming to the requirements of GDC-2 as 
they apply to the buried portions of the auxiliary SWS lines from Lake 
Anna to the main SWS header providing that compensatory measures as 
described herein are continued for the period of the exemption.
    Pursuant to 10 CFR 51.32, the Commission has determined that 
granting the above exemption will have no significant impact on the 
quality of the human environment (October 7, 1993, 58 FR 52332).
    The subject Phase 1, Stage 4 SWS GDC-2 exemption is effective from 
its date of issuance through October 14, 1994.


    Dated at Rockville, Maryland this 27th day of December 1993.

For the Nuclear Regulatory Commission.
 Gus C. Lainas,
Acting Director, Division of Reactor Projects--I/II, Office of Nuclear 
Reactor Regulation.
[FR Doc. 93-54 Filed 1-3-94; 8:45 am]
BILLING CODE 7590-01-M