ML20071F327
| ML20071F327 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/04/1983 |
| From: | Fiedler P GENERAL PUBLIC UTILITIES CORP. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-03-04.D, TASK-3-4.D, TASK-RR NUDOCS 8303110101 | |
| Download: ML20071F327 (6) | |
Text
.
GPU Nuclear QQ g7 P.O. Box 388 Forked River, New Jersey 06731 609-693-6000 Writer's Direct Dial Number:
Mr. Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Crutchfield:
Subj ect: Oyster Creek Nuclear Generating Station (OCNGS)
Do eke t No. 50-219 SEP Topic No. III-4D Aircraf t Hazard Site-Proximity Missiles As part of the Systematic Evaluation Program (SEP), aircraf t strike probabilities were evaluated for aircraf t impact on OCNGS. The probabilities were estimated for three size categcries including small general aviation, medium-sized commercial, and large commercial or military aircraf t.
The methodology and results of the evaluation are described in the attac*nent to this letter. The results indicate that probabilities for an aircraf t strike on the plant for all categories are extremely low based on available traf fic information.
Very truly yours,
/1 A I_'
V Peter B. Fiedler Vice President and Director Oyster Creek PBF:jal At tachment cc:
Mr. Ronald C. Haynes, Administra tor Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 NRC Resident In spect or Oyster Creek Nuclear Generating Station Forked River, NJ 08731 8303110101 830304 PDR ADOCK 05000219 P
PDR GPU Nuclear is a part of the General Pubhc Utihties System
ATTACHMENT SEP TOPIC No. III-4D AIRCRAFT HAZARD Aircraft strike probabilities were estimated for three size categories including small general aviation, medium-sized commercial, and large (heavy) commercial or military aircraft.
The nearest airports of significance are at Lakehurst, 16 miles north-northwes t and McGuire Air Force Base about 24 miles northwest.
At these distances there is no significant hazard due to landing and takeoff activites.
Low level military training routes in the area must be kept more than 5 miles from the plant by agreement between the military and the NRC.
There is little t ra f fic along these routes, and at this distance they represent an extremely low hazard to the plant.
There are several conunercial routes within 10 miles of the site shown on the aeronautical charts as V312, an east-west route nearly over the plant and V44-229 r u n ning northeast-southwest about 16 miles southeast of the plant. Traffic along these routes is generally above 8,000' near the plant.
The holding pat tern at the LEGGS intersection passes about 2 miles east of the plant at its closest approach and is used infrequently.
The Enroute High Altitude chart shows the closest jet route J55-121 to be about 10 miles east. Traffic along this route would not constitute a significant hazard to the plant.
There is a considerable amount of general aviation, light aircraft traf fic activity in the area which is not aligned with any specific route. Informal surveys by plant personnel provided the basis for assumptions in this study for general aircraft activities.
Based on evaluation of the available information on air traffic conditions at the site, which showed that portion of the air routes (which are 4 nautical miles wide) are located near the site and that the frequency of use is low, it is concluded that the only potential hazard necessary to be evaluated is from the traf fic along the V312 airway and general aviation in the area.
Probabilities for a strike on the plant are developed below for three sizes of aircraft based on available traffic information for each size, 1.
GENERAL AVIATION The probability of a strike on vital areas of the plant is estimated by the following relationship:
PsGA = RGANdA /A p g PsGA " Probability of a general aviation aircraft strike on vital (yr 1).
plant area RGA = accident rate for general aviation aircraf t (mi-1 ).
p area (mi2 ),
A
= vital plant l
A
= observation area (mi2),
o N
= number observed in Ao (yr
),
d
= average distance across observation area (mi).
Surveys by plant personnel indicate overflight by small aircraft occurs at an average annual frequency of less than three per day.
This
. study assumes 1,000 overflights per year with a 5% condifence lower bound of 300 and an upper bound of 3,000.
2 2
The target area A is assumed to be 80,000 f t (0.0028 mi ),
dich is approximately double the area of vital plant features to account for skid path and effective target area due to the taller structures.
The ocertainty in A is expressed by assuming the vital areas could be a
p factor of 4 smaller but only a f ac tor o f 1.5 larger than assumed A
2 1-mile radius is assumed for the observation area, Ao = 8.7 x 10 ft
( 3.14 m i 2).
An uncertainty factor of plus or minus 2 is assigned to the area of observation, A. The fatal accident rate for general aviation is o
about 0.3 accidents per 106 miles flow. An uncertainty of a lower value of 0.1 and a high value of 0.7 is estimated. The average dis tance flown in the circular observation area, A, is assumed to be d=1.5 miles with o
uncertainty bounds of 1.84 and 0.44 based on an equal chance of traversing 95% and 5% of the area of the circular observation area.
Table I summaries the resul ts for general aviation aircra f t.
The general aviation aircraft hazard is assume to be characterized by a missile weight of 6,000 lbs which is the approximate average weight for aircraft considered in the general aviation class.
2.
MEDIUM-SIZED COMMERCIAL AIRCRAFT The V312 airway passing over the site is 4 nautical miles wide on each side of the centerline.
The relationship used to determine the probability of a strike on the plant is taken from the NRC's Standard Review Plan, Section 3.5.1.6, as follows:
P
= RNA /W gg p
P
= probability of a medium-sized aircraft strike on the plant 33
( y r - 1).
R
= in-flight accident rate for medium-sized aircraft, assumed average weight of 150,000 lbs (mi-1).
N
= number of flights along airway (yr -l).
A
= area of plant vital structures ( mi -2 ).
p W
= width of airway (mi).
Based on the National Transportation Safety Board's published statistics covering 10 years of commercial flight, the rate for all fatal I
l
accidents is about 0.002 per million miles flown.
In-flight accidents constitute about one-third of the total fatal accidents; therefore, R=0.0007 x 10 -6 mi-1 The une bound of 0.0003 x 10 grtainty is estimated to be represented by a lower mi and an upper bound of 0.0009 x 10-6,i, The number of flights along V312 in this size class is estimated by personnel contacted at the McGuire Air Force Base and the Kennedy Air Traf fic Control Center to average less than 60 per day; therefore, N=
20,000 per year.
The assumed uzcertainty range is 10,000 to 25,000.
The vital plant area is assumed to be 160,000 f t' (0.0057 mi2) including a l a rg er s k id path and an effective target area due to tall structures.
This area is assumed to be larger than for general aviation aircraf t due to the greater momentum at impact which could result in the aircraft sliding into the plant. This is conservative since aircraft falling from the higher altitudes used along this airway would likely have little forward velocity on impac t.
Velocity is expressed by assuming the upper bound is a factor o f 1.25 higher a nd a factor of 4 less for the lower bound. The width of the airway is 8 nautical miles or W = 9.2 mi.
All aircraft are assumed to be in this corridor.
Substituting in the equation yields the results for medium sized aircraft shown in Table II, 3.
LARGE AIRCRAFT Military air traffic heading east f rom McGuire Air Force Base frequently utilize V312.
Most aircraft are of the cargo type in the 300,000-1b or greater size class typified by the C-141.
The safety record of these aircraf t is about the same as for the commercial carriers previously discussed.
Large commerical aircraft apparently do not normally utilize this airway.
The same relationship is used for flights of heavy aircraf t, i.e.,
J Pg = RNAp /W = probabilty of a heavy aircraft strike on the plant (y r-1).
Assuming there are less than ten heavy flights per day along V312 or N = 3,000 per year with a range of from 1,500 to 4,000 and that R, Ap, and W do not differ from the analysis presented previously for 4
medium-sized aircraf t, the probabilties shown in Table III are computed.
Greater uncertainties are placed on accident frequencies since the data base is ccusiderably smaller than for the smaller aircraf t.
L
TABLE I
GENERAL AVAIATION STRIKE FREQUENCIES, YR-1 Parameter R
^
^
"GA GA p
o
~
Mean
- 0. 3 x 10 1,000
- 1. 5 0.0028 3.14
- 4. O x 10
~
9 *
~
- 0. 7 x 10 3,000
- 1. 84 0.0042 6.28
- 2. 6 x 10
~
Upper Bound 5% Confidence
~9 0.1 x 10" 300 0.44 0.0007 1.57
- 5. 9 x 10 Lower Bound
~I Variance
- 4. 75 x 10 1
9
TABLE II MEDIUM-SIZED AIRCRAFT STRIKE FREQUENCIES, YR-1 r
Paramete r R
N A
W P
p M
-9 Mean
- 7. O x 10-
- 2. O x 10 0.0057
- 9. 2
- 8. 7 x 10 95% Confidenc
-10 4
~0
- 9. O x 10
- 2. 5 x 10 0.007
- 9. 2
- 1. 7 x 10 Upper Bound
~
- 1. O x 10 0.0014
- 9. 2 7. 6 x 10~
- 5. 0 x 10 Lower Bound
- 1. 09 x 10-14 Variance TABLE III LARGE AIRCRAFT STRIKE FREQUENCIES, YR-1 Parameter R
N A
w P
p H
~I Mean
- 7. O x 10
- 3. O x 10 0.0057
- 9. 2
- 1. 3 0 x 10" 95% Confidence
-9 3
-9
- 1. O x 10
- 4. O x 10 0.007
- 9. 2
- 3. O x 10 Upper Bound 5% Confidence
- 1. 5 x 10 0.0014
- 9. 2
- 6. 8 x 10
- 3. O x 10
-11 Lower Bound Variance
- 4. 6 x 10~
b
- - _ _ -