ML20234E919
| ML20234E919 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Bodega Bay |
| Issue date: | 06/30/1964 |
| From: | Mcdonald J ARIZONA, UNIV. OF, TUCSON, AZ |
| To: | |
| Shared Package | |
| ML20234A767 | List:
|
| References | |
| FOIA-85-665 NUDOCS 8709220564 | |
| Download: ML20234E919 (3) | |
Text
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. QUMMARY OF REPORT i1 h
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, M6teorological Aspects of. Nuclear %eactor; Hazards dt(Bode a Ba by'Dr. James E. Mcdonald,lSenior Physicist d -
t , Institute of Atmospheric, Physics, University gof Arizona M fune; 1964 4 ,. .- Certain meteorological conditions peculiar to the Bodega Bay area and to the northern California coast have quite adverse implications fo: radiological hazards that could
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I arise from a major reactor accident.
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j One extremely adverse meteorological feature for which fairly reliable data are at hand l i is the high frequency of inversions that would act to ponfine radioactive effluents 4 release in any accident The inversion frequency at Oakland, California, averages 70 , per cent of all days for the summer months of June to September. At Oakland, for the year as a whole, 40 percent of the days have inversion bases at or below 1500 feet. c r. y The frequency of low inversions at a coastal site such as Bodega Head is certain to be O. E even greater'than in Oakland,because air reaching Oakland has, in general, been sub'-
- ..gc jected to some overland warming. Furthermore, ocean surface temperatures just
.--v;7 -r - offshore band of upwellingand upwind watersofoff Bodega Head Californi'a, are known increasing local to be among tendencies the stability, toward lowest alo if Inversion studies by U.C.L.A. meteorologists have shown that the intensity of the 90- ' inversion is particularly strong near Bodega and at coastal points northward % Cape Mendocino . Mean summer inversion-layer thickness of about 1500 feet, and mean j % ~. inversion magnitude (temperature increase from cool base to warm top) of about 1200 i
W4,7~ near Bodega makes the inversion extremly effective as a lid preventing deep mixing of ) l any radioactive effluents from an accidental release.
#Cr j #7 With auch high frequency and unusual intensity of low inversions it is difficult to 1 jpgz .
visualize a less desirable locality in which to have a serious reactor accident. l I NN iM.j Following the Company's submission of a new design concept to compensate for fault 1
;--m =- movement through the site, the Atomic Energy. Commission's Director of Regulation, I r_1 Mr. Harold L. Price,(letter: May 19, 1964) recentip asked P.G. & E. how it proposes to l modify its design so that "(1) the structure and leak tightness of the containment build '
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ing would not beimpaired.? (ii) the ability to shut down the reactor and maintain it in
- the shut-down condition would not be imparied? (iii) primary systems would remain intact? and (iv) supply of power to the facility would not be interrupted?" Director i
Price proceeds to still more specific queries about location and safeguards proposed for " vital internal components" and'especially about the emercency cooline system. N The latter query is directed to a crucial' point, for with the original triple containment barrier potentially reduced (by major seismic accident) to the single barrier of the reactt vessel, the question of reliability of the emergency cooling system required to dispose i of post-accident fission decay heat assumes major importance. Possibility of a whole series of seismically induced malfunctions in the complex automatic control systems that must swing into operation in event of accident draws attention to the possibility b of failure of the standby systems design to deliver emergency cooling to the reactor core. Such a failure would insure meltdown of the core, a prerequisite to escape of the volatile fission products. With'the outer two containment barriers breached, core meltdown would leave only the reactor vessel as the sole containment barrier. The further possibility (admitted by PG&E in its estimate of the " maximum credible accident' Mh1.E 8709220564 851217 -
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y . , -[ . ' specified in its 1962 Pr'eliminary Hazards Summary Report) that seismically induced ! failures of other components of the safety system might event'uate in breaching of 1
) that one last barrier returns our attention to the meteorological factors that would govern radiolo'gical exposure hazards in event of such an accident.
,The foregoing remarks have been aimed primarily at drawing attention to the fact that there has been a' substantial drop in claimed integrity of the Bodega reactor as a result of recent geological and seismological findings at the site. The peculiarly adverse meteorological factors associated with the Bodega site assume much more serious proportions in the face of these reductions in claimed integrity.
It should be noted that serious radiological exposures are obtained for an assumed j escape of only 80 megacuries of the total of approximately 200 megacuries of y! volatile fission products, or about one-third of all the volatiles. One-third of the j i volatile fission products accumulated in the Bodega reactor core at equilibrium
! represents, in turn, approximately 6 or 7 per cent of the total fission product
~- inventory in the equilibrium core of Bodega No.1 Reactor. Even that small a i fractional escape of total fission products would produce catastrophic results.
~ The foregoing summary of seismic potential for major accident and of hazard dimen- >
sions should suffice to show that one must, indeed, weigh into the over-all assess-N, ment of desirability of constructing a complex of reactors at Bodega Head the -l 7" question of the adverse meteorological features of the area, for the possibility AJ - that those features would be brought into play seems much greater now that the pros-i pect of a major release has essumed its recently acquired credibility. 1 c. m Cf The meteorological difficult'ies are compounded by the unusually high persistence g of winds blowing out of the northwest. The marked tendency for northwest winds ;
.O blowing onshore from the Pacific anticyclone means that effluents caught under the gdh inversion lid would tend, in general, to drift towards the populous areas and milk- l f shed areas of'Marin and Sonoma Counties.
l 9. Furthermore, recent studies carried out in connection with forest-fire meteorology 5 investigations, have clearly established that a well-developed summer sea-breeze r system prevails in the "Petaluma gap", the corridor of low terrain running inland
= from Bodega to the Petaluma and Cotati Valleys. During the daytime hours, marine D'
air penetrates into inland areas beyond Petaluma and Santa Rosa. Past field studies on the extent of inland penetration required to break down inversions in the los Angeles area indicate that it is almost certain that the inversion lid would still be present E' in air currents reaching, say, Petaluma and Shnta Rosa; so a reactor accident that happened to occur between morning and mid-afternoon, during summer months, would almost certainly lead to radiological exposures in those and other inland communities. g During evening and early morning hours, weak counterblow (land breeze) is to be expeued through the Petaluma gap, but quantitative data on the nighttime land breeze are non-existent. This is a very serious lack of meteorological information. It
' seems probable that weak land-breeze flow would cause radioactive effluents from Bodega to drift a short distance out to sea before being caught in the prevailing i northwesterly flow. Thus any reactor accident that occur ed during the nighttime j hours in the summer half-year is likely to inject effluents into coastwise-drifting '
air heading toward the second principal gap in the coastal ranges, the Golden Gate.
- The fact that stability of the inversion and sub-inversion layers would be even greater at night implies substantially less lateral dispersion for nighttime drift of effluents towards the Golden Gate than for daytime drift of effluents through the Peta- l
; luma gap. It seems entirely possible that effectlye radioactive plume widths of only !
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babout,1p-15 miles coult .e characteristic of effluents re. )ing the Golden Gate, f'
-{penhaps only half those for Santa Rosa or Petaluma, implying perhaps twice as high concentrations 1,n San Frsncisco) .
I^ Smoke expe~riments carried out at Brookhaven National Laborator'es and elsewhere !
.have established that under the kind of highly stable inversion conditions present j . under summer nighttime condU. ions along the California coast, effluent plumes can 6 l drift for manytens of miles with almost no turbulent mixing or spreading, so high
' plume concentrations could persist to and through the Golden Gste. The monsoonal I inflow of inarine air through the Golden Gate into the San Francisco Bay area is so .
strong as to persist, th6 ugh with reduced intensity, even during nfghttime hours. ! Hence there is high probability that effluents drifting down the coast from Bodega - l
' to the Golden Gate would be mainly swept inland to endanger the large population ,
center of the Eay area. i I Thus, in summer, pasence of a sea-breeze system in the Petaluma gap is of over- J riding importance in any assessment of radiological hazards of the Bodsga reactor ! site. It is disquieting to find no discussion of this sea" breeze system in the meteor- {
-2 olgical section of the Preliminary Hazards Summcry Report filed by the Pacific Gas 1 I
~~; atd Electric Company as part of the application for a construction permit. Much .
more needs to be known about both the day'ime and the nighttime portions of that I e=-j sea-breeze system before reliable quantitative estimates of radiological hazards may ! M be made; but on the basis of existing knowledge, I regard the meteorological factors j gh. as peculiarly adverse. ! i b - A reactor accident taking place during the winter half-year would involve rather different meteorological factors than would a suauner accident. In winter, stability
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conditions would generally favor rapid vertical mixing of accidentally released q 7 ,,j radioactive effluents, and wind directions are also more variable. However, even j
.1 ~ in the winter wet season, coastal inversions are relatively common (as contrasted 1
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{ egg with other areas of the country), and northwesterly winds are still the prevailing winds . The distinctive featutes of winter weather on the California coast is the j i A.f occurrence of frequent light rains or drizzles (3 approximately one day in three has l some precipitation near Bodega in winter) implying correspondingly high probability bs of rain-washout of radioactivity. Deposition of radioactivity on the milkshed areas F(9 of Sonoma County, and panicularly of Marin County, would become the most serious !
- r. r :D hazard accompanying a major accident during the wet winter months. Only the still I'
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wetter coasts of Oregon and Washington excel the northern California coast in winter with respect to probability of serious rain washout of reactor-accident effluents . N Note must be taken here of the extremely poor siting of the meteorological tower that has been set up on the Head to gather data on the diffusion climatology of the
- reactor area. This tower lies directly downwind of steeply ascending slopes on the west side of the Head. Steady-state turbulence fields will almost never prevail at this tower location, renderinq application of existing diffusion theories almost h impossible. Furthermore, aerodynamic acceleration of low-level winds sweeping up the slopes of the Head towards the tower is likely to give spuriously favorable indication of intensity of the prevailing field of turbulence. I do not see how re-liable estimates of the turbulent diffusion conditions actually prevailing at stack height can be obtained without erection of additional towers, or else a much higher tower at the present site.
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- I would stress in conclusion, the pressing need for much more extensive and much more careful investigation of all meteorological factors bearing on Bodega reactor hazards . Inversions, prevailingly northwest winds, sea breezes.and land breezes, rain washout, fog and stratus washout and deposition, and details of diffusion climatology must be much more thoroughly understood before safe estimates of radiological hazards can be made for the Bodega site.
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