ML14138A126
| ML14138A126 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 05/03/1983 |
| From: | Paulson W Office of Nuclear Reactor Regulation |
| To: | Dietch R Southern California Edison Co |
| References | |
| TASK-02-01.C, TASK-2-1.C, TASK-RR LSO5-83-05-006, LSO5-83-5-6, NUDOCS 8305050038 | |
| Download: ML14138A126 (21) | |
Text
May 3, 1983 Docket No. 50-206 LS05-83-05-006 Mr. R. Dietch, Vice President Nuclear Engineering and Operations Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770
Dear Mr. Dietch:
SUBJECT:
SEP TOPIC II-l.C, POTENTIAL HAZARDS DUE TO NEARBY TRANSPORTATION, INSTITUTIONAL, INDUSTRIAL AND MILITARY FACILITIES - FINAL SAFETY EVALUATION FOR THE SAN ONOFRE NUCLEAR GENERATING STATION,',UNIT 1 By letter dated December 27, 1982, the staff issued a safety evaluation report on this topic. Your letter of April 21, 1983, provided corrections to this evaluation. Enclosed is our final evaluation of SEP Topic II-1.C for the San Onofre Nuclear Generating Station, Unit No. 1.
We conclude that the probability of explosions exceeding.5 psi over pressure at the site, due to accidents involving materials on both Route 1-5 and the Atchison Topeka and Sante Fe railroad, is about 4.5x10-6 per year.
This exceeds current criteria, however, the analysis includes sufficient conservatisms such that the risk is judged to be substantially lower than the above value. With regard to these calculations it is requested that the shipment frequencies in the second paragraph of Section 5.2.2 be updated to assure that assumptions made in the evaluation are accurate.
(\\ This evaluation will be a basic input to the integrated safety assessment USe o/
for your facility unless you identify changes needed to reflect the as-built conditions at your facility.
This assessment may be revised in the future if your facility design is changed or if NRC criteria relating to this subject are modified before the integrated assessment is completed.
- 4 6y Sincerely, pGriginal s igned bf Walter A. Paulson, Project Manager 9305050038 3050 Operating Reactors Branch No. 5 ORB DR ADOCK 05000206 Division of Licensing OR PDR_
DCr ield
Enclosure:
As stated 5/ /83 OFFICE
... cc w/encl sure: See naxt page.
SEB.....SEPB I
SEPB SURNAME EMcKenna:bl CGrimes WRussell WP u1son DATE 5/08/83
/3.,83 5/t /83 5/9 /83 NRC FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COPY USGPO: 1981-335-960
Mr. R. Dietch, Vice Pres ht Docket No. 50-206 NuclearEngineering and Operations San Onofre 1 Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770 cc Charles R. Kocher, Assistant General Counsel James Beoletto, Esquire Southern California Edison Company Post Office Box 800 Rosemead, California 91770 David R. Pigott Orrick, Herrington & Sutcliffe 600 Montgomery Street San Francisco, California 94111 Harry B. Stoehr San Diego Gas & Electric Company Post Office Box 1831 San Diego, California 92112 Resident Inspector/ San Onofre NPS c/o U.S. Nuclear Regulatory Commission Post Office Box 4329 San Clemente, California 92672 Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego San Diego, California 92101 California Department of Health ATTN:
Chief, Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 95814 U.S. Environmental Protection Agency Region IX Office ATTN:
Regional Radiation Representative 215 Freemont Street San Francisco, California 94111 Robert H. Engelken, Regional Administrator U.S. Nuclear Regulatory Commission, Region V 1450 Maria Lane Walnut Creek, California 94596
San Onofre Nuclear Generatig Station, Unit I 5&
aftyAses~sment Report Topic 1 -c Potential Hazards or Changes in Potential Hazards Due to T r a n s p o r t a t~
o I
I f S 'l t u t i o n a l I d u t i, a d M v a r
1.0 INTRODUCTION
The objective of this topic is to assure that San Onofre Unit 1 is adequately protected and can be operated with an acceptable degree of safety with regard to Potential accidents which may occur as thie result of activities at nearby industrial, transportation, and military facilities.
2.0 CRITERIA Standard Review Plan Section 2.2.1-2-2.2 states that-a11--i-dentified facilities and activities within 5 miles of the-Plantr-Should be reviewed.
Facilities and activities at greater distances should be considered if they otherwise have the Potential for affecti'ng safety-related features.
Standard Review Plan 2.2.3 defines design basis events external to the station as those accidents for which amrealistic estimate of the annual probability of exceeding 10CFR100 exposure guidelines is Int excess of approximately 10-7 or for which a conservative estimate of t i pr b il y is n ex ss f approximately 10-6.,o fi rbblt si xeso 3.0 RELATED SAFETY TOPIc 5'AND INTERFACES A.
Topic 111-4.0, Site Proximity Missiles (Including Aircraft), October 23, 1981.
B. SCE submittals on NUREG-.0737 Item 111.0.3.4 - Control Room Habitability, June 13,Cand June 20, 1981.
C. San Onofre Nuclear Generating Station, Units 2 and 3 FSAR.
- 0. Analysis of Hazards For Rail and Highway Transportation Routes Near San Onofre Nuclear Generating Station, Unit 1, NUS-4099.
4.0 REVIEW-GUIDELINES Standard Review Plans 2.2.1, 2.2.2 and 2.2.3 were used s review guielines 5.0 EVALUATION Data for hazardous materials, frequency of shipments of ha e
and accident rates were extracted from the San Onofre Units 2 and 3 FSAP an(
are reproduced here for completeness.
Adaitional data and analytic FetRnocs are contained in Reference 0. These,data were analyzed for +ter fec n
Unit 1, t.aking into account differences in plant design cri teria and location with respect to transportation routes.
-3 Where firing or weapon impact is permitted, training is conducted under very close supervision since populated areas, the highway, railroad, and infantry maneuvering areas are located along the seacoast of the reservation to a distance of approximately 5 miles inland.
Firing ranges are shown on U.S. Geological Survey (1968), 7.5 minute quadrangle sheets:
San Clemente, Margarita Peak, San Onofre Bluffs, and Las Pulgas Canyon.
The nearest firing range (approximately 3 miles away) is a known-distance range over which small arms are used to gain sighting data.
The maximum range of firing is about 100 feet, with rounds impacting into a steep hillside.
All other firing ranges are generally inland from Camp San Onofre and located such that the maximum range of the weapons would not permit an impact closer than approximately 2miles from the plant, even assuming firing was directed toward the plant rather than into the designated sectors.
Firing is also directed into hillsides or valleys to avoid any danger of projectile skipping.
Aircraft practice firing and artillery bombardment is controlled at all times and is directed into impact areas located further than 5 miles inland.
Aircraft approaches and pullouts do not pass near the plant.
There are two bombing and strafing ranges located approximately 6 miles from the plant. Various types of aircraft delivered ordnance of up to 500-pound bombs are employed on these ranges.
No bombardment from the sea is ever permitted, and the snore landing maneuvers do not involve the use of live ammunition. Thus, Marine Corps activities which could otherwise-conceivaoly constitute a hazard to the plant are all conducted well away from the coastline and do not constitute a credible hazard to plant safety.
Tne Marine Corps indicated that there are no missile sites on Camp Pendleton and none within at least 10 miles of Unit 1.
5.1.3 Transportation Routes The three transportation routes within 5 miles of the plant are described below:
(1) The old Highway 101, immediately east of the site, does not carry through traffic, but is the entrance road to the south end of San Onofre State Beach.
(2) Interstate 5 (1-5) is east of the site and is the only public coastal vehicular link between Orange County and San Diego County.
Tne 1974-75 estimated average daily.traffic was 63,570 vehicles, with an estimated passenger population of 130,240. The years 1970-1974 -averaged 3,572 trucks per day adjacent to the plant.
Th1s figure includes vehicies over 5,000 pounds, with two or more axles, Out does not include buses, vans, campers, and pickups.
A. Size:
12-inch diameter B. Age:
It was constructed in several phases. The section from 0.4 miles northwest to 1.6 miles northwest of the plant was built in 1932. The section from 1.6 to 1.9 miles northwest was constructed in 1960. The section from 1.9. to 2.8 miles northwest was built in 1966. The section from 2.8 to 5.0 miles northwest was built in 1929. And the section from 0.4 miles northwest to 5.0 miles southeast of the plant was built in 1966.
About 0.1 miles of pipeline 3.3 miles north of the plant was replaced in 1963.
C. Operating pressure:
400 psig (maximum allowable)
- 0. Depth of burial:
30 inches average E0 Location:
See Figure 1. The pipeline is located approximately 673 feet northeasterly from the centerline of Unit 1 containment. The pipeline is located within the right-of-way of U.S. Highway.101, approximately 5 feet southwesterly of the northeast edge of the right-of-way.
F. Valves: There are three plug valves located 1.3 and 2.8 miles northwest of the plant and 2.1 miles southeast (see Figure 1).
G. Material:
Natural gas (91% methane, 5% ethane, 4%
miscellaneous)
H. Storage:
The pipeline is not used for gas storage I. Future plans:
There are no plans for expansion or to use the pipeline for a product other than natural gas.
J. Leaks:
There have been two leaks within 5 miles of the plant.
One, in 1967, was approximately 3.5 miles north of the plant, a small corrosion leak with no fire or explosion. The other, in 1963, was approximately 3.3 miles north of the plant, a breaK in the pipeline due to exterior stress, with no fire or explosion. Repair was made by replacing 449 feet of pipe.
(3) San Diego Pipeline Company -
10-inch refined petroleum products pipeline 2 to 5 miles northeast of the plant in Camp Pendleton., The characteristics of this pipeline are:
A. Size:
10-ihch diameter B. Age:
Constructed in 1962 C. Operating pressure:
1,440 psi (maximum)
-7 The number of shipments of hazardous cargo shipped on 1-5 adjacent to the plant is given in the second column of Table.1. Several of the cargo categories used for presenting the survey results in Table 1 contain a number of different materials. Table 2 lists the various cargoes contained within these categories.
The expected number of military explosive shipments past the plant on 1-5 was estimated to be 1,411 for the year June 1978 through May 1979. The Navy stated that chnges in shipment routes and requirements for 911 of the shipments would occur after 1980 so that there will be less than 10% of the 911 shipments. Assuming that the remaining shipments are unaffected, the projected 1-5 military explosive shipment frequency is 592.
The maximum net explosive weight per I-5 shipment is 11,400 lbs.
5.2.3 Waterways The principal uses of the coastal waters are pleasure boating, industrial cooling, military exercises, and sport-and commercial fishing. Commercial vessel traffic lanes lie at distances greater than 5 miles from the plant.
Military exercises are discussed elsewhere in this report.
5.2.4 Projections of Industrial Growth There are no plans for expansion of existing facilities or new industrial development with 5 miles of the plant. Existing pipelines and waterways are also not scheduled for expansion.
San Diego County, in conjunction with the CALTRANS, has forecast an increase of 45% in truck traffic on I-5 in the vicinity of the plant. Razardous cargo snipments are expected to decrease on 1-5 as a percent of total shipments because increased industrialization in San Diego will provice these products locally.
Fuel shioments (gasoline, LPG, LNG, etc.) may decrease in absolute number because OT tne aevelopment of these processing tacilities in San Diego and the increasing cost to ship fuels by truck.
Explosive shipments by the U.S. Navy will remain constant to the U.S. Marine Corp Camp Pendleton and will decrease for other shipments.
Industrial gas and chemical shipments will vary as a function of future industrial process requirements, availability from local sources, products manufactured and shipment costs.
The largest increase in truck activity can be expected in food and other consumer products.
5.3 EVALUATION OF POTENTIAL ACCIDENTS The accidents considered in this section include:
- 1. explosions of hazardous materials,
- 2. delayed ignition of flammable vapor clouds,
- 3.
liquid spills,
- 4. release of toxic vapors,
- 5. offsite brush fires, and
- 6. accidents at sea.
-9 Correction factor 1973 accident rate 0.952 x 10 1971-72 accident rate (2.19 x 10
+ 2.31 x 10-6)/2
= 0.423 This factor is applied to the 1-5 accident rates based on the assumption that California accident rates would be reduced by the same proportion as that observed on the national level.
The fact that the California threshold is
$200.00 vs. $250.00 for the U.S. DOT would make the correction factor a conservative assumption.
The 1-5 accident rate for all trucks corrected to the $2,000.00, death or injury reporting criteria:
0.423 x 0.566 x 10-6 = 0.239 x 10-6 accidents/truck-iile The bulk of hazardous commodities carried on 1-5 past the plant are in tank trucks.
Nationwide truck accident statistics show that loaded tank trucks have a lower accident rate than all types of trucks combined (1.33 x 10-6 vs. 2.41 x 10-6 for years.1968 through 1972 with the same reporting criteria).
Therefore, the 1-5 accident rate for all types of trucks (0.239 x lu-6 ) is corrected to loaded tank-truck accident rate by assuming the same relative improvement exists in California (1-5) as observed nationwide.
Loaded tank truck = 0.239 x 10-
= 0.132 x 10-6 accidents/mile accident rate on I-5 2.41 x 10 The accident rate for trucks carrying explosives was determined in a similar manner. The nationwide accident rate for trucks carrying explosives is 0.96 X 10-6 accidents/mile. Therefore, the accident rate for trucks carrying explosives on 1-5 is:
Explosive Truck = 2.39 x 10-x 0.96 x 10-6
-0.95 x 10-7 accidents/mile accident rate 2.41 x 10 5.3.2.2 Explosions Due to Transportation Accidents on I-5 There are three categories of materials transported on 1-5 whicn have a potential for creating a hazard for San Onofre Unit 1 in the event of an accident on the highway.
These materials are military ordnance, flammaole liquids and flammable gasses (shipped as either compressed liquid or compressed gas).
5.3.2.2.1 Military Ordnance The expected numoer and size of explosive snipments past the San Onofre site are shown in Table 7.. This table is based on information proviced y he Departments of tne Army and Navy.
The explosives are Class 7 (1 pouno or explosive is equal to 1 pound of TNT).
-11 R = KW1/3 where:
R = distance from explosion site to point of interest K = constant related to overpressure
= 131 feet/1bl/ 3 for 0.5 psi W = weight of explosive (lb)
Thus:
Li = 3.79 x 10-4[(131W1/ 3 + 240)2 - 7802]1/2 miles The probability of exceeding 0.5 psi overpressure at the site due to a munitions truck accident on 1-5 is calTulated to be 1.92 x 10-per year.
All other explosive shipments past the plant are Class 8 explosives which, in
.general, function by rapid combustion rather than detonation and therefore do not pose an explosion hazard to the plant.
5.3.2.2.2 Flammable Liquids Flammable liquids are shipped at ambient temperature and pressure and would not pose an explosion hazard unless vaporized. The nature of the explosion or fire for the flammable liquids listed in Table 1 is dependent on the chemical and physical properties.of the materials.
These chemicals, in general, have low vapor pressures and high vapor densities. Thus, the vapor formed tends to hug the ground, and only a thin vapor interface exists between the air and the liquid. Therefore, spilled liquids are unlikely to produce an explosion with a strong blast wave but will produce a simple flash-over flame igniting the remainder of the fuel.
A review of the materials shipped indicates that gasoline has the highest vapor pressure and therefore the highest evaporation rate.
The next most volatile liquid shipped is acetone. For gasoline, the estimate downwind distance to the lower flammable limits is estimated to be less than 460 feet compared to minimum distance to the plant from the highway of 635 feet.
This calculation assumes Class G stability, 1.43 m/sec wind speed and 1000F temperature for evaporation.
For acetone, the distance to tne lower flammable limit is less than 120 feet.
From the above, it is concluded that because of their low vapor pressures, flammable liquids shipped past San Onofre do not contribute to the overpressure or flammable cloud hazards at the plant.
-13 For vapor cloud explosions, it is common practice to utilize a TNT equivalent calculated as follows:
=
F
/Q E
500 Kcal/lb - TNT (3)
F = Fraction of spill quantity involved in vapor cloud
= gm-mole of combustible chemicals spilled Si = spill fraction Q = maximum quantity of shipment in volume 3 = density of liquid A = mulecular weight Kr-a 1 SHe = Heat of combustion ( mo E = Yield of explosion For liquified gases shipped at atmospheric temperature under their own vapor pressure, the fraction of spill quantity in the vapor cloud is the isenthalpic flash fraction.
For compressed gases it is 1.0.. These values are consistent with the conservatively assumed instantaneous puff release model.
For cryogenic liquids shipped at essentially atmospheric pressure, a 10% flash fraction was used to account for initial vaporization on mixing with warm air and boiling from the spilled liquid pool.
The entire quantity in the cloud as assumed to be involved in the fuel air reaction.
The change in the quantity of vapor between upper and lower flammable limits as the cloud.disperses was conservatively neglected.
Analysis of a drifting puff release has shown that the maximum quantity between flammable limits is on the order of 60-70% for materials of interest here and that for much of the travel distance, it is less than this amount.
To obtain the equivalent.TNT yield, the ranrge of explosion yields reported in the literature were surveyed and Table 9 compiled. In Table 9, the yields are roughly combined so as to approximate a value for probability distribution.
The given values of the yield are applied to the total quantity of material released from the tanker, rather than the flash fraction.
This is consistent with the way that the yield has been defined in the literature.
Equations 2 and 3 give the maximum distance from any structure at which the explosion involving a particular commodity could yield the specified overpressure.
The length of route within this distance of a plant safety related structure can be obtained from the geometrical plant layout shown in Figure 4. This length (and the size of Region I) is spill size and commodity dependent.
-15 considered. The CrosSwind distance is effectively added to the boundary of Region 1 to determine the Prooabillty of a flammable cloud being swept into a plant air intake.
Most Spills of flammable vapor are ignited essentially at the accident site.
For example, Statistics from theAssociation of American Railroads indicated that for 81 vapor cloud ignitions, 58% occurred from a few feet up to 50 feet, 181 between 50 and 100 feet and 24% from 100 feet to 300 Feet.
Integrated ignition probability as a function of distance from historical data for LPG spill accidents were published in "Risk Assessment of Storage and Transport of Liquified Natural Gas and LP-Gask by J. A. Simmons.
The data indicates that 10.5% of the drifting cloud ignitions resulted in an explosion while 89.5% resulted in a fire.
The magnitude of explosions is dependent on the chemical and physical properties of the materiapl.;-For LPG, LN, and liquified hydrogen, the amount of flsning of liquid to vapor was calcul ated from the enthalpy differences at the cryogenic shipping condition and at atmospheric pressure. The enthalpy of combustion of a Stoichiometric fuel-air mixture for each of the flammable gases was equated to.the enthalpy of detonation of TNT. For the unconfined vapor cloud explosions of LPG and LNG it was assumed that the maximum yield of the TNT equivalent weight was based upon the probability distribution discussed above.
For hydrogen and acetylene, it was conservatively assumed that the maximum yield was 100Qf the. TNT equivalent weight. Analys s shows that the probability of exceedingg.en psi is 0 fbr LNG and 3.93 x 10" for I i qu if ied hyd rogen.
The annual probability of an overpressurization from a release of LPG was frpalisticaJ analyzed as an extension of the previous analysis using the following modified inputs:
(1) The single value of pos sible accident locations on 1-5 has been replaced by a distribution across the southbound lanes and shoulder.
(2) Sixty percent of the LPG shipments on 1-5 are in tandem trilers with a maximum of 5,000 gallons available for involvement in a vapor cloud detonation. Forty percent are in single tankswith a capacity of 10,000 gallons available for involvement in a vapor cploud detonation.
(3) The single yield of explosion has been replaced by a distribution of yields whicil is applied to the entire quantity of material released.
A review of LPG shipment data on 1-5 shows that most shipments are soutboouna or on the si-de -of-,the highway nearest the plant.
The possible acciden~t locations used in the realistic analysiswere derive from acual truck accident locations along the ten-mile stretcnof 1-5 near te plant.
The resulting locations and the assigned relative prObdolitier are:
-17 Another possible cause of damage to the plant is a fireball generated by the explosion of tank trucks on 1-5.
Ignition of a 10,100 gallon LPG tank consuming the entire contents would result in a fireball with a radius of 156 feet with a duration of 7.4 seconds.
Since the outer dimension of the fireball is a minimum of 479 feet away from the nearest safety-related building, a fireball caused by an LPG tank truck will not be a hazard to the plant.
5.3.2.2.3 Release of Toxic Gases Due to Transportation Accidents on 1-5 Toxic chemicals are transported along 1-5 on a regular basis. Tables 1 and 2 list the observed materials transported past the site and thei-r estimated frequency of shipment.
The following five substances have been identified as a result of the pro abilistic risk assessment as having probabilities near to or greater than 10- /years:
(1) Chlorine 1 x 10-6/year (2) Butane lx 10- 6/year (3) Gasoline 1 x 10-6/year (4) Ammonia 9 x 10- 7/year (5) Propane 2 x 10- 6/year As a result of the control room habitability review performed on Unit 1 as required by NUREG-0737 Item 111.0.3.4-Control Room Habitability, the Unit 1 control room HVAC will be replaced. The new HVAC system will include an automatic isolation feature sensitive to the above chemicals.
5.3.3 Transportation Accidents on the Atchison, Topeka, and Santa Fe Railroad Hazardous materials transported past San Onofre on the AT&SF railroad track are military ordnance and LPG. The AT&SF Railway Company does not anticipate any other hazardous materials being shipped through the San Onofre area.
5.3.3.1 Accident Rates for AT&SF.
Railroad accident rates were determined from data supplied by the AT&SF Railroad for a section of track from Fullerton, California to San Diego (102.5 miles) and passing by San Onofre. Data is for 11 years between 1968 to 1978.
During this period, there were 26,378 trains and 10 accidents.
Therefore, the accident rate for trains passing San Onofre is:
10 accidents (102.5 miles)(26,378 trains) = 3.70 x 10-6 accidents/train mile
-19 It has been estimated that there were 1.98 x 107 explosive train-miles per year based on statistics for a 57 year period from 1917 to 1973.
The annual average train miles during this same period was 1.36 x 109. During this 57-year period there were 35 explosions involving in-transit shipments of explosives. The national annual probability of an explosion due to a train accident involving explosives is.3 1 x I-8 explosions per explosive train mile. The accident rate for the AT&SF is significantly less than the national average. Therefore, using the ratio of AT&SF to the national rate, the probability of an explosion on the AT&SF is 1.05 x 10-8 explosions per explosive train mile. The IIT report also deseeR-ted'a significance factor to account for those accidents which did not yield a significant explosive overpressure. This significance factor is 0.154.
The probability that a munitions train explosion on the AT&SF will cause a peak positive normal reflected pressure at the station which exceeds 0.5 psi is estimated by the following equation:
Pop z Pex x SF x ENiLi where Pp = The annual probability of an overpressure at the station Pop exceeding the design basis overpressure of 0.5 psi Pex = probability of an explosion per AT&SF explosive train mile (1.05 x 10-8)
SF = significance factor (0.154)
Ni = the number of munitions train shipments/year which carry a total of Wi pounds net explosive weight past the San Onofre site Li = the critical length of track over which the detonation of Wi pounds of TNT would produce an overpressure at the station exceeding the design basis overpressure of 0.5 psi Values for Wi and Ni assumed for the calculation are given in Table 6.
The length of track, Li, is calculated in a manner similar to that for explosions on 1-5, discussed above.
Assuming the entire explosive cargo of a train detonates in-mass, the annual probability or peak positive normal reflected overpressure at the station exceeding 0.5 psi caused by ordnance detonations on the AT&SF track, is 2.0 x 10-8.
This number can be considered to be conservative, and the actual probability of occurrence is expected to be much lower since, if an explosion were to occur in a boxcar of ordnance of the type normally shipped past San Onofre (small arms ammunition) it is more likely to detonate in small individual oursts rather than as a single large blast. Overpressures experienced at the site would be correspondingly lower.
-21
- 0. Type.IV - This type of incident would be caused by a leak, a tank puncture, a released safety valve or a burst transfer line or valve resulting in a controllable fire. The fire may be of considerable time duration and does not result in tank rupture, either due to fire control measures or protective insulation.
This type of incident is characterized by a controllable fire with no explosion.
E. Type V - This type of incident would involve a leak or a puncture, either small or large, which does not result in fire. If no source of ignition occurs, the liquid will be dispersed in the atmosphere in a relatively short time.
This type of incident is characterized by loss of lading, but no fire.
Reviewing the information available about the incidents cited above, it is concluded that these 163 tank car accidents can be classified as follows:
Type Number Frequency of Occurrence I
3 0.0184 11 19 0.1166 III 54 0.3313 IV 4
0.0245 V
83 0.5092 In addition to the mechanical damage, exposure of LPG cars to fire can lead to explosions. There were 17 incidents involving 49 LPG tank cars during the period of 1965-1970, These accidents can be classified as follows:
Type Number Frequency of Occurrence 1
0 0.0 II 39 0.796 111 2
0.041 IV 7
0.143 V
1 0.020 Although fuel-air detonations from fire-induced loss-of-lading accidents are conceivable, it is not credible that the escaping gas would fail to detonate very near the car (the heat from the fire which caused the tank car failure would also be available to initiate the detonation). The probability of a delayed detonation for these cases is accordingly assumed to be zero.
One hundred thirteen carloads of LPG were shipped past the San Onofre site during the first 11 months of 1975.
The annual frequency of shipments is taken to be 124 LPG cars/year, based upon the opinion of the AT&SF that there will be minimal future growth in LPG haulage. The AT&SF has also stated that there are no more than two or three LPG tank cars in any one train.
-23 Using an average train length of 70 cars and 10 cars involved in the accident, the annual probability of a Type TI rupture due to non-LPG tank car induced fire is 6.5 x 10-8 per track mile.
The combined annual probability for Type IT rupture from all causes is 4.2.1 x LO-.6.
If it is conservatively assumed that all Type II events will proauce one rocketing fragment, the total annual probability-that an LPG tank generated fragment strikes a safety-related structure of the unit is 2.0 x 10-8.
The effects of missile impacts on the plant are discussed in the assessment of Topic III-4.0, Site Proximity Missiles (Including Aircraft).
5.3.4 Accidents Involving Natural Gas Pipelines A 12-inch nature gas pipeline is located approximately 510 feet from the nearest safety-related plant structure.. An analysis has been performed to determine the likelihood of a pipeline accident that leads to an unacceptable concentration of 4.4% natural gat at the air intake and is documented in the San Onofre Units 2 and 3 FSAR. The analysis results in a negligibly small probability (6.75 x 10- 9/year) of intersection of the 4.4% concentration with the plant intake. The analysis is also applicable to and conservtive for San Onofre Unit 1 for the following reasons:
- 1. The terrain at Unit 1 is similar to that at Units 2 and 3. However, the bluff between the plant and the pipe line is both higher and steeper at Unit 1 than at Units 2 and 3. Therefore, flow separation from the ground is more likely for Unit 1.
- 2. The Unit 1 control room air intake is at a lower elevation than Units 2 and 3. Therefore, the gas concentration would be lower at the intake for Unit 1 than Units 2 and 3.
- 3. The Unit 1 air intake is farther from the pipe line than Units 2 and 3.
5.3.5 Offsite Fires Offsite fires are not considered a credible hazard to the plant.
5.3.6 Accidents at Nearby Industrial and Military Facilities There are no significant manufacturing plants, chemical plants, refineries, wells, oil or gas storage facilities, or mining operations within 5 miles of the site. Hazards associated with the Camp Pendleton Marine Corps base are discussed above.
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REGION II DEFINED BY THE BUILDING LAYOUT I-5 Radius = 240' 780' Diesel Generator Building Co trol.
Building Containment Turbine Building Fuel Stor-,
age Ventilation Reactor Equipment Auxiliary Building 13U
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Table 1
BAZARDOUS CARGO TRAFFIC ESTIMATES (Sheet 1 of 2)
.nnual(a)
Average MaxiMMb)
Cargo Type Shipments Shipment Size Shipment Size Flasmable Liquids Gasoline 17*000 8,600 gal 9.000 gal Diesel oil 650 7,600 gal 7,900 gal Jet fuel 910 8,000 gal 9,000 gal Solvents (See table 2
)
Miacellaneous Petroleum Products (See table 2
)
71ammable Gasses Propane (LPG) and Butane 2,200 9,700 gal 10,100 gal LNG 420 9,200 gal 9,200 gal Hydrogen (liquid) 52 8,500 gal Hydrogen (gas) 260 38 -
219 ft3 75 -
219 ft3 cylinders cylinders 24 (c) 10 -
11,400 ft3 10 -
11,400 ft 3 Bydrogen (gas) cylinders cylinders Acetylene
- 10 330 ft cylinders
- a.
Estimate of annual shipments based on survey at truck weighing sta tion except where shipper estimates exceeded that number.
- b.
Maximum size is based on the actual observed shipments.
- c.
Not actually observed, identified through a questionnaire survey of all chemical manufacturers in the region.
Table 2
INFREQUEN A
DOUS CARGO SHIPMENTS (Sheet 1 of 2)
Chemica1 Shipment Size Solvents (a)760ga Acetone 7,600 gal Diactoe 2,600 gal xylene (24 annual shipments b) 7,500 gal Shell.SQL M-75 1575 gal TOLU-SOL-6 975 gal Naptha 2,725 gal Methanol(a) 1,000 gal Ms 20H 8,000 gal Pentachlorophenol 20,000 lb Miscellaneous Petroleum Products Benzene 300 gal Manor oil 34,000 lb (typical Formaldehyde (6
0 (14 annual shipments(b))
6,000 gal Weed oil 54,000 lb Crude oil 7,600 gal Hydraulic oil 3,900 gal Perchloroethylene, 4,000 gal Methyl butyl ketone 1,000 Methylene chloride 3,800 gal Methyl ethyl ketone 13,000 lb Ethylene dichloride(a) 1,000 Butyl Acetate 22,000 lb Epoxy 1,000 lb Poisons and Pesticides Methyl bromide 3,500 lb Corrosives Hydrochloric acid 40,000 lb SurfuFic acid 3,340 to 50,000 lb Muriatic acid 3,120 lb Nitric acid(a) 2,800 lb
- a.
Not actually observed; identified through a questionnaire survey of all chemical manufacturers in the region
- b.
Based on shippers estimate
Table 3A SUMMAR' OF DATA SUPPLIED BY CALIFORNLA DEPARTENT OF TRANSPORTATION Number Accidents per.
Calendar TukMlsof Accidents
-0 ie Year n 1-5 120.---
1974 20.38 x 10 20.453 1975 19.88 x 106 9
0.687 1976 21.83 x 106 15 0.530 1977 22.65 x 106 12 0.566 Combined 84.74 z 106 48 Table 33 U.S. DOT INTERCITY UICWAY TRUCK ACCDENT RATES PER MILE a Accident oReported ie s
an injury oFatality CAl d TOeot e
ciden
-6 RaInter 0-6 Rate x 10-6 aearil 2.19 1.0
.0 Mi83 19717 1250 2-31 0.996 0.081 1972 588302 0.07 1973 C i2000 0.952 160
.41 a, Acidet alo reorte ii there was an injury or fatality.
Table 3C NATIONAL TRUCK ACCIDENT RATES caledar otalintecity Total Intercity Accident Rate CYenar Total Miet Accidents per 106 Miles 198110 x16 29209 2.50 1968 11701 x 106 07 2.46 1970
.12390 x 106 3 0 2.19
.1971 13951 x 106 30581 2.19 1972 15883 x 106 36 ----
2.31 Combined 66389 x 106 160347 24
Table 5
ASSUMED BOX CAR WEIGHT DISTRIBUTION OF ORDNANCE TRANSPORTED BY RAIL PAST THE SAN ONOFRE SITE Net Explosive Weight/Boxcar Boxcar Shipments/yr (ib) 1 37,000 1
25,500 4
25,000 10
-20,000 15 15,000 25 13,000 15 10,000 10 6,000 2
3,000 1
400 84 boxcars/yr Table 6
ASSUMED SHIPMENT WEIGHT DISTRIBUTION OF ORDNANCE TRANSPORTED BY RAIL PAST THE SAN ONOFRE SITE Mtfunitions Train th14ments/Yr' Total Net Explosive Weight/Shipment Si W (1bs) 1 62,500 2
50,000 5
40,000 7
30,000 1
28,000 12 26,000 7
20,000 1
16,000 4
-12,000 1'
9,000 1
3,400 42 shipments/yr
TABLE 7 HIGHWAY MILITARY EXPLOSIVE SHIPMENT SIZE DISTRIBUTION Net Explosive Number 7 Length of 1-5 of Weight (lbs)
Shipments Interest (miles) 0-3400 559 0.783 3400-4400 6
0.820 4400-5400 6
0.886 5400-6400 5
0.942 6400-7400 5
0.993 7400-8400 4
1.038 84U0-9400 3
1.080 9400-10400 3
1.118 10400-11400 3
1.154 594*
The actual expected number of shipments per year is 592. This sum is greater because fractional shipments calculated from the size distribution were rounded up to the next higher number.