ML20008F602
| ML20008F602 | |
| Person / Time | |
|---|---|
| Site: | Allens Creek File:Houston Lighting and Power Company icon.png |
| Issue date: | 04/20/1981 |
| From: | Campe K Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20008F600 | List: |
| References | |
| NUDOCS 8104210362 | |
| Download: ML20008F602 (11) | |
Text
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04/20/81 UNITED STATES OF A!1 ERICA NUCLEAR REGULATORY COMMISSION BEFORE THE AT0!11C SAFETY AND LICENSING BOARD In the !!atter of
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HOUSTON LIGHTING & POWER C0!!PANY
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Docket No. 50-466
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(Allens Creek Nuclear Generating
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Station, Unit 1)
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NRC STAFF TESTIMONY OF KAZIMIERAS li. CA!!PE RELATIVE TO THE TEXAS UTILITIES C0:1PANY'S 24-INCH NATURAL GAS PIPELINE RELOCATION AND OTHER PIPELINES CROSSING THE BRAZ0S RIVER
[ Bishop Contentions 4, 5,'7, 9 and 10]
Q.
Please state your name and position with the NRC.
A.
My name is Kazimieras M. Campe.
I an employed at the U.S.
Nuclear Regulatory Commission as a Site Analyst in the Siting Analysis Branch.
Q.
Have you prepared a statement of educational and professional qualifications?
A.
Yes.
It is attached to this testimony.
Q.
What is the purpose of your testimony?
A.
Tne purpose of my testimony is to respond to Bishop Contentions 4, 5, 7, 9 and 10.
I will address each of these contentions separately below.
Q.
What do Bishop Contentions 4-5 allege?
A.
Bishop Contentions 4-5 state as follows:
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Bishop Contentions 4-5 Moving the Texas Utilities Company'I 24-inch natural gas pipeline to the proposed route will increase the danger to the people in the city of Sinonton and particularly to those people who live in the Valley Lodge subdivision.
This move alto creates an increased hazard of pipeline rupture.
Specifically, the new route runs the pipeline very near the bank of the Brazos River, which could give way due to unstable soil or undercutting during floods.
Q.
In general, what sort of danger, if any, would a natural gas pipeline represent to people in its vicinity?
A.
In the event of a pipe rupture, the escaping natural gas can act as a simple asphyxiant and, if ignited, produce fires and explosions.
Q.
Is it possible to quantify the extent of the potential for asphyxiation with respect to the relocated 24-inch natural gas pipeline?
A.
Yes. Assuming that the 24-inch natural gas pipeline was ruptured and not isolated, and if the escaping gas remained unignited, some portions of the ensuing gas cloud could displace a sufficient amount of oxygen in the ambient air such that asphyxiation would be a hazard.
Normal oxygen content in air is about 21% by volume. The minimal oxygen content should be 18% by volume in order to avoid asphyxiation. Thus, methane concentrations in excess of 3% by volume could lead to asphyxiation.
The maximum distance that could be reached by methane of such concentration is estimated to be about 2800 feet. This is based on the conservative assumptions that the atmospheric condition is Pasquill Stability F with a wind speed of 0.8 M/SEC, and that the methane cloud remains near ground level.
Since methane is lighter than air, the cloud would have a tendency to rise, so that the maximum distance at ground
. t level would be less than the above esticate.
In any event,- the esticated raxican distance for methane to act as an asphyxiant is nach less than the shortest distance betaeer. the relocated pipeline and the Valley Lodge subdivision (i.e. 2833 feet versus approxinately 10,233 feet).
Q.
- ' hat is the extent of the fire hazard associated with the a
relocated 24-inch natural gas pipeline?
A.
In the event of a pipe rupture, the escaping natural gas could be ignited by various sources of ignition in its vicinity. The flancability licits for oathane are approxicately in the range fron 5% to -
15% by volune. The farthest distance from the pipeline that can be reached by nethane in concentrations of 5% or more can be esticated by assaning Pasquill Type F atnospheric stability with a 0.8 M/SEC wind speed. Inis distance is about 2300 ft.
A conservative esticate of the distance at which the radiant heat flux frar. the burning nethane cloud would approach extreae pain is about 1900 feet. This is based on the conservative assunpticns that the entire contents of the gas cloud within the lower flaamability envelope is b rning, that the burning is in the fully turbulent regice, that the cloud is of constant width and height corresponding to the caxicuo value between the pipeline and the extrece downwind distance, that the cethane cloud is not buoyant and retains near ground level, and that atmospheric transnissivity to thernal radiation at all wavelengths is 1.0.
Hence, the caxinum distance at which 'detrinental effects to people could be caused by a burning = ethane cloud is li=ited to less tnan 2330 feet plus 1900 feet, or a total of about 4200 feet.
This di2~ 'cc is significantly less tnan the nearest distance fron the Valley lodge subdivision to the relocated 24-inch pipeline.
T
Q.
Is there a potential for an explosion with respect to the natural gas pipeline?
A.
In the event of a pipe rupture, it is theoretically possible that the escaping methane could detonate. A detonation is an explosion that propagates through the explosive material at a constant speed which exceeds the speed of sound in tha' material. - A detonation within an unconfined flammable gas'and air mixture can occur only if the gas properties are brought to an initial state which meets the Chapman-Jouguet conditions.
For flammable methane-air mixtures, more than a cubic meter must be initially shocked by some means into the Chapman-Jouguet conditions to initiate a detonation. Typical ignition sources in the vicinity of the pipeline (e.g. automobiles, power transformers, electrical switches) would be insufficient to induce the conditions prerequisite for a detonation.
It is this reason that, in general, accidental detonations of methane-air mixtures have not been observed and are considered virtually impossible. Thus, the 24-inch natural gas pipeline, either in its present or in its relocated position, does not pose an explosion hazard with respect to the Village Lake subdivision.
Q.
What are your conclusions regarding the potential effects of the relocated 24-inch gas pipeline on the people in Simonton and the Valley Lodge subdivision?
A.
Estimates of the potential effects of asphyxiation, fires, and explosions indicate that the reolcated 24-inch pipeline will not be a hazard to these communities. The estimates are based on the conservative assumptions tht the pipe rupture is a double ended break, that the e
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natural gas is allowed to escape without isolation (i.e., no leak detection or isolation equipment is assuned), that the cloJd is not buoyant, and that the meteorology is stable (Pasauill Type F).
Q.
Has the Staff analyzed the stability of the Brazos River bank and determined whether bank erosion could cause rupture of the gas pipeline?
A.
No.
For purposes of responding to these contentions and determining the potential hazard to nearby residents, the Staff assumed that the gas pipeline would rupture and did not analyze the possible causes of such rupture.
Q.
What does Bishop Contention 7 allege?
A.
Bishop Contention 7 states as follows:
The proposed re-routing of the Texas Utilities Coapany % 24-inch gas line 50 that it goes parallel to and very close to the cooling lake di,a creates a safety hazard.
The line could burst and through explosion or erosion breach the cooling lake dan and release the lake water. At least two serious consequences could result:
(1) people could be ki'. led and property destrofed in the area cue to flooding, and (2) the plant could be left without adequate cooling water. The line should be re-routed, or the dam redesigned to withstand the forces associated with a gas explosion and erosion.
Q.
What is the likelihood that the relocated 24-inch natural gas pipeline would rupture and the escaping methane ignite?
A.
From previous reviews of natural gas pipelines, the Staff has determined that the probability of pipe rupture and ignition is about 2.7 I
X 10-5 per mile of pipe per year. Since the relocated pipeline near the cooling lake daa is about 4 miles in length, the likelihood for pipe rupture and ignition near the daa is about 1.1 X 10-4 per year.
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Q.
What is the likelihood that a rupture in the relocated 24-inch natural gas pipeline would cause a breach in the dr.1 such that the cooling lake water would be released?
A.
Although quantitative estinates beyond pipe rupture and gas ignition have not been made, it is considered virtually impossible _for a nethane-air mixture to detonate because of the lack of high energy ignition sources close to the pipeline (see NRC Staff Testimany on Bishop Contention 4-5).
In addition, if detonation did occur, it is extreuely remote that the explosion would breach the dan.
Q.
Assuming that a detonation did occur, and that tne dan was breached, what would be the consequences with respect to the ACNGS and the surrounding area "downstreaa" of the dan?
A.
In the event of a breached cooling lake dam, the loss of cooling lake water would not be a safety hazard to the ACNGS. The plant will have a 47-acre ultimate heat sink which will not be affected by the drainage of any of the cooling lake water. The flooding associated with the loss of cooling lake water is estinated to have a minimal localized uffect.
Q.
What are your conclusions with respect to Bishop Contention 7?
A.
The rupture, ignition, and detonation of escaping natural gas from the relocated 24-inch pipeline, sufficient to breach the cooling lake daq and drain the lake, is judged to be an extremely unlikely event.
s Notwithstanding the low likelihood of such an event, the postulated loss of cooling lake water does not affect plant safety due to design features of the ultimate heat sink. The flooding of the surrounding area is not expected to be significant.
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Q.
What does Bishop Contention 9 allege?.
A.
Bishop Contention 9 states as follows:
The Applicant cannot effectively detect and deactivate a leaking section of the 24-inch natural gas line. Moreover, the potential exists for a greater than anticipated detonation energy release due to'other than pure methane being discharged fron a leak or rupture. The Applicant should reevaluate the assumptions used in his analysis and prove that tne plant is designed to uithstand the detonation.
forces that could t.nanate from various combinations of cloud size, yield, etc.
Q.
To what extent is the ability to detect and isolate a leak in the 26-inch pipeline related to the safety of the ACNGS?
A.
In the event of a pipe leak, immediate leak detection and isolation would limit the amount of natural gas released.
It may also limit the size of the flancable gas cloud. The Applicant's analysis of the 24-inch natural gas pipeline does r.at take credit for quick detection and isolation of the pipeline.
Its estimates of the natural gas release are based conservatively on the assumption of a double ended pipe rupture and an uninterrupted discnar'ge for 2.5 hout s.
In previous analyses of similar natural gas pipelines, the Staff fcund that maxinun cloud volume was achieved in less than an hour. Beyond about an hour, the flamnable region or size of the natural gas cloud does not increase due to atmospheric oispersion and buoyancy effects. Since the ACNGS was shown to be capable of withstanding the detonation forces caused by the ignition of a flammable natural gas cloud of maximua size, the ability to detect and isolate is not required.
l Q.
To what extent can the variability in cethane purity affect the esticated detonation effects?
tO
. s A.
Natural gas is typically at least 85 percent nethane and about 10 percent ethane. The rest consists of small amounts of propane, butane, nitrogen and trace amounts of other impurities. The maximun effect vf the non-methane constituents can be estinated by conparing the TNT equivalent yield of a pure hydrocarbon with the yield of a mixture.
Specifically, one may compare the distance of a given overpressure when detonating a pure hydrocarbon versus the corresponding distance when a mixture of two hydrocarbons is detonated. Let us assume that the pure hydrocarbon has the lowest recomended value of TNT energy equivalence, i.e., X = 0.20.
To maximize the effect of the " impurities," let us e
assume that the nixture consists of 85 percent of the los yield hydrocarbon and 15 percent of the highest recommended TNT energy equivalence, i.e.,d
= 0.40.
Since the distance for a given e
overpressure varies as the cube root of TNT energy e uivalence, then a comparison of the above pure and mixed hydrocerbons yields a distance ratio of 0.8 for the distances to the scae overpressure. Hence, the assumption of pure methane in the Applicant's analysis is not very sensitive to overpressure estimates. NotJ thstanding the above considerations, it is the Staff's view that detonation of natural gas-air nixtures is virtually impossible because of the lack of high energy ignition sources in the vicinity of the pipeline (see Staff Testimony on Bishop Contention 4-5).
Q.
What does Bishop Contention 10 allege?
A.
Bishop Contention 10 states as follows:
Nunerous pipelines carrying a variety of potentially dangerous substances cross the Brazos upstream of the plant.
If such a pipeline broke, the River could
carry large anounts of flammaale and/or corrosive materials downstream to the plant via the cooling lake intake. The material could enter the cooling lake and create a hazard to the plant.
Q.
Do the pipelines crossing the Brazos upstrear,of the plant pose a significant risk to the safety of ACNGS?
A.
No.
Q.
What is the basis for your conclusion?
A.
The major rupture or uncontrolled release from a liquid carrying pipeline is a relatively rare event, being on the order of 2 X 10-3 per mile of pipeline per year based on Department of Transportation data (National Transportation Safety Board, NTSB-PSS-78-1).
Furthermore, the rupture of a pipeline in itself is not an immediate threat to the plant.
The plant normally draws its cooling water from the cooling lake.
In order to have the possibility of any effect on plant operation, the liquids escaping from a pipeline and transported along the Brazos would have to enter the cooling lake via the make-up pumping station. This is not very likely because the make-up pumps take suction near the bottom of the River.
Liquids lighter than water (such as crude oil) would not be expected to enter the pump intakes, since they would be floating on the surface of the River.
Liquids which are capable of mixing with water throughout the depth of the River would be diluted in proportion to the i
volume of River water between the pumping station and the ruptured pipe.
i Thus, its potential effects on plant operation, if any, would be diminished. The probaiblity of adverse effects on plant operation is further reduced since the make-up water pumping is done at specific times, not continuously. The Applicant intends to periodically observe i
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the inconing mate-up water. Hence, it is possible to stop punping in the event of water contamination. Ultinately, contamination of cooling lake water (e.g., wita crude oil) could potentially affect heat exchanger performance. This in itself is not an imediate safety-related effect and upon detection can be corrected by routine maintenance without affecting plant safety.
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KAZIMIERAS M. CAMPE PROFESSIONAL QUALIFICATIONS ACCIDENT ANALYSIS BRANCH DIVISION OF SITE SAFETY AND ENVIRONMENAL ANALYSIS I an a member of the Siting Analysis Branch of the Office of Nuclear Reactor Regulation of the United States Nuclear Regulatory Commission.
My duties include the identification and evaluation of hazards to the safe operation of nuclear power plants due to accidents external to those plants. This includes the review of design basis accidents leading to hazards such as fires, explosions, missile impacts, and toxic gases.
In addition, ny duties include the performance of probabilistic risk assessments with respect to various froms of transportation, including pipelines.
Prior to being assigned to the Siting Analysis Branch, I was a member of the Accident Evaluation Branch as a Nuclear Engineer.
I graduated from the University of Connecticut where I received B.S. and M.S. degrees in Mechanical Engineering in 1958 and 1960, respectively.
Between 1960 and 1962 I completed some advanced mathematics courses at the Rensselaer Polytechnical Institute branch in East Hartford, Connecticut.
During this period I was employed by Pratt and Whitney at the CANEL Analytical Physics Group as an analytical engineer.
From 1962 to 1966 I attended Purdue University, where I received a Ph.D. in Nuclear Engineering.
From 1966 to 1972 I was employed by Hittman Associates, Inc. where I worked in the Radioisotope Departaent. During this period my responsibilities included radiation shielding analyses, radioisotopic generator design, _
and computer code development for reactor core physics calculations.
Since 1972 I have been employed by the Nuclear Regulatory Commission in the Accident Analysis Branch, f
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