ML19221A853
| ML19221A853 | |
| Person / Time | |
|---|---|
| Issue date: | 02/17/1972 |
| From: | NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | |
| References | |
| REGGD-01.023, REGGD-1.023, NUDOCS 7907100112 | |
| Download: ML19221A853 (6) | |
Text
2/17/72 SAFETY GUIDE 23 ONSITE METEOROLOGICAL PROGRAMS A. INTRODUCTION Thus, at each nuclear power plant site there are multiple needs for an onsite program which Subparagraph 100.10(c)(2) of 10 CFR Part will adequately measure and document basic 100 states that in determining the acceptabihty meteorological data. These data may be used to of a site for a power or testing reactor, the develop atmospheric diffusion parameters Co m mission will take into consideration which, with an appropriate diffusion model,8 meteorological conditions at the site and in the may be use.1 to estimate potential radiation surrounding area.
doses to the public resulting from actuai toutine or accidental releases of radioactive matenals to Subparagraph 50.36a(a)(2) of 10 CFR Part the atmosphere or to evaluate the poential dose 50 tequires nuclear power plant licensees to to the public as a resuit of hypothetical reactor submit semiannual reports specifying the acc dents. This safety guide describes a suitable quantity of each of the principal radionuclides onsite meteorological program to provide released to unrestricted areas in hqu,d and in meteorological data needed to estimate these i
gaseous effluents, and such other information as potential radiation doses.
twy be required by the Atomic Energy Commission to estimate maximum potential B.
DISCUSSION annual radiation doses to the public resulting An onsite meteorological measurements from effluent releases. A knowledge of program at a nuclear wer plant site should be meteorological conditions in the vicinity of the capable of provi g the metecrological reactor is important in providing a basis for information required to make the following estimating maximum potential annual radiation assessments:
doses resulting from radioactive materials 1.
A conservative assessment by the released in gaseous effluents.
applicant and the regulatory staff of the potential dispersion of radioactive Ir order for the Commission to fulfill its material from, and the radiological r e s po n sibilities under the National Envirobotal Policy Act of 1969, and in conseqyences of, design basis accidents to aid m evaluating the acceptability of accordinre with the requirements of Appendix a site and the adequacy of engineered D to 10 CFR Part 50, " Statement of General safety features for a nuclear power Policy fnd Procedure: Implementstbn of the National Environmer,tal Policy Act of 1969 plant.
2.
An assessment by both the applicant (Public Law 91 190), basic meteorological and the regulatory staff of the information must be available for use in maximum potential annual radiation assessing potentially adverse environmental dose to the pubhc resulting from the effects of a radiological and nonradio!cgical routine release of radioactive matenals nature resulting from the construction or In gaseous effluents to assist in operation of a nuclear power plant.
demonstrating that operations will be A p pe ndix E to 10 CFR Part 50, or are being conducted within the
" Emergency Plans for Production and limits of 10 CFR Part 20 end to assure Utilization Facilities." requires each applicant that effluent control equipment design for an operating lic-nse to include in its final objectives and proposed operating safety analysis report required by Q 50.34(b) of procedures meet the Commission's 10 CFR Part 50. plans for copmg with requirements for keeping levels of radiological emergencies. The plans must include radioactive material in effluents to crit eria for determining when protective
'S*Itty Guide 3."A22umPrions Used for Evaluating measures should be considered within and W PotenM RadMogical Consequences of a b of outside the site boundary to protect health and Coolant Accid nt for Boiling Water Reactors, 9
safety and prevent damage to property. In th.is November 2,1970; Safety Guide 4." Assumptions Used regard, it is necessary for the applicant to for Evaluating the Potential Radiological Consequences establish and maintain a meteorological program of a 1.ots of Coolant Accident for Pressurized Water capable of rapidly assessing critical Reactors." November 2.
1970. " Meteorology and meteorological parameters.
Atomic Energy-1968." TID '4190.
09 23.1 7 907100 l/l2.
unrestricted areas as low as practicable.
S pe cific guidance for evaluating the 3.
A realistic assessment by the applicant potential radiological consequences of design I
and the regulatory staff of the potential basis reactor accidents is gisen in Safety Guides dispersion of radioactive materials 3 and 4. The basic diffusion model desenbed in f ro m, and the radiological these guides may also be used to estimate the co n sequences o f, a spectrum of dispersion of radioactive materials in the accidents to aid in evaluating the atmosphere following the routine or accidental environmental risk posed by a nuclear :: lease of such materials. When using the model power plant in accordance with for evaluating short-term releases, the actual Appendix D to 10 CFR Part 50.
meteorolopcal parameters measured during the 4.
A realistic assessment by the applicant release period should be used. For long-term and the regulatory staff of other than releases the observed j oint frequency radiological environmental eficcts, such distnbution of wind speed and direction and as foggmg, icing, and salt drift from atmospheric stability for the period should be cooling towers, to aid in evaluating the used. In the event of large variations in the rate environmental impact of a nuclear of release, it may be necessary to subdivide the po w er plant in accordance with meteorological data into periods of Appendix D to 10 CFR Part 50.
a;9toximately uniform release rate.
5.
A rapid, conservative assessment by the While there are differences in the specific licensee and other appropriate persons types of meteorologicalinformation required for of the radiological consequences of an each of the above assessments, a single set of accidental release of radioactive instruments can generally be used to obtain the matenal to the atmosphere. The basic data ne-ded for all of them. For this assessment should be used to provide reason, when establishing a meteorological early guidance to persons assigned to program for an initial site survey, careful licensee's emergency organization and consideistion should be given to the operational to appropriate local, State and Federal needs of the plant for meteorological agencies with responsibilities for coping information. In particular, care should be taken wit h emergencies, for use in to locate the stations at positions where the determining (i) the need for measurements will accurately represent the notification and participation of local overall site meteorology and, if possible, where and State agencies and the Commission wind pa tterns will not be significantly and other Federal agencies, and (ii) nfluenced by plant structures.
when appropriate measures should be The number of locations on a site at which taken to protect public health and meteorological measurements are necessary will safety and prevent damage to property depend largely on the complexity of the terrain in accordance with Appendix E to 10 in the vicinity of the site. For example, the CFR Part 50. Onsite meterological study of a hill-valley complex, or a site near a measurements should provide an large body of water would require a larger adequate basis for short distance number of measuring points to determine air a t mos phenc diffusion calculations.
flow pa t terns and spatial variations of (Regional rneteorological data will be atmospheric stability.
needed in the event it should become The minimum amount of meteorological necessary to make diffusion estimates data needed for siting evaluation is considered to for long distances. To assure that the be that amount of data gathered on a required data are readily available. the continuous basis for a representative consecutive apphcant should establish and maintain 12 month period. Two full annual cycles of data cont act with the nearest National are desirable.
W ea t her Service Focal Point Air Polludon Meteorologist.)2 C.
REGULATORY POSITION
- The name and address of the nearest Focal Point This section describes a suitable onsite Aar Pollution Meteorolog2st may be obtained by contacting the Air Pollution Meteorolog.st, Weather meteorological program to provide Analysis and Pre diction Dmsion, National Weather meteorological data needed to estimate potential Se rvice. National Oceangraphic and Atmospheric radiation doses to the public as a result of the Administration, Silver Sprmg. Maryland 20910.
routine or accidental release of radioactive 125 110 23.2
materials to the atmosphere and to assess other control room for use during plant ens ironmental effects.
operation.
1.
Meteorological Parameters.
4.
Instrument Accuracy To obtain the meteorological in formation required for a valid a.
Wind direction accuracy for estimate of atmospheric diffusion at a instantaneous recorded values 5 *.
particular site, instrumentatior should b.
Wind heed accuracy for time be provided that is capable of averaged values 20.5 mph. Striting measuring wind direction, wind speed, speed of anemometer < l mph.
and ambient air temperatwe at a c.
Temperature accuracy for time minimum of two levels on at least one averaged values
- 0. 5' C.
tower or mast. At sites where there is a Temperature difference accuracy potential for fogging or icing due to 27 from either difference between i n c r e a se in at mospheric moisture pveraged t temperatures or average content caused by plant operation, temperature difference 10.l*C.
instrumentation should be provided for d.
Dew point accuracy for time measuring the dew point (or humidity) averaged values 10.5'C.
on the tower or mast.
5.
Instrument Maintenance and Servicing 2.
Siting of Meteorological Instruments.
Schedules The tower or mast should be sited at Meteorological instruments snould be approximately ;he same elevation as inspected and serviced at a frequency finished plant grade and in an area which will assure at least a 90% data where plant structures will hav; little or recovery and which will minimize no influence on the meteorolo2 cal extended periods ofinstrument ot.tage.
i m e asurements. The lower set of The use of redundant sensors and/or instruments should sense wind speed itcorders may be another acceptable and direction,. termperature, and dew means of achieving t:te 907c data point (where required) at an elevation recovery goal. The instruments should of 10 meters above the ground and the be calibrated at least semiannually.
apper set should sense wind speed and direction and temperature at the height 6.
Data Reduction and Compilation of release of radioactive material (plant-a.
Wind. temperature and humidity vent height) but should be positioned data should be averaged over a not less than 30 meters above the lower period of at least 15 minutes at sensor set. For stack releases, another least once each hour.
set of sensors should be located at an b.
The basic reduced data should be elevation such that meteorological compiled into monthly or seasonal conditions at stack height can be and annual j oint frequency represented.
distributions of wind speed and wind direction by atmospheric 3.
Data Recorders stability class. Table 1 gives an Either analog (strip chart) or digital example of a suitable format for recording of data may be used as a basis data compilation and reporting for analysis in lieu of providing purposes. Simitar tables of joint redundant dig.ta! recorders, digital frequency distnbution should be outputs may be supplemented by scrip prepared for each uf the other chart iecorders to minimize possible atmospheric stability classes. Table loss of Cata due to instrument 2 presents a classification of the malfunction. Recorders (analog or various a t mos p heric stability digital) for wmd directio, and speed categories.
.ad t e m r erature difference (two c.
To aid in assessing the impac' of t e m pe ratures or one temperatu[
7 33g pla n t operation on the dif ference measurement on a tower br, J l 1i ens.ronment. joint frequency masti should be located in the reactor distribution rypes of data 213
?
summaries should be compiled calculation procedures described.
which will permit the description The probabilRy distributions of of the frequency and extent of X/Q estimates for appropriate time fogging and icing conditions caused periods should be presented, by plant operation.
7.
SpecialConsiderations d.
When evaluating the acceptability of a site for a nuclear power plant, At some sites, due to complex flow because of unique meteorological patterns in nonuniform terrain, additional wind and temperature co.iditions at the site, it is i n s t ru m en t a1io n and more sometimes necessary or desirable to depart from the meteorological comprehensive programs may be assumptions provided in Safety n e cessary. Also, measurements of Guides 3 and 4. In these cases, precipitate, n and/or solar radiation when reducing the data, it is may be de:Irable at some locations.
necessary to analyze the joint Occasionally the unique, diffusion frequency of persistent wind characteristics of a particular site may direction, wind s peed, and warrant use of special meteorological atmospheric stability to determine nstrumentation and/or studies.
a p pro pr;a t sly conservative Proposed studies of this n1ture should atmospheric diffusion factors be described in the application for a (X/Q) for time penods over which construction permit.
the release is assumed to occur 'up to 30 days).
8.
Documentation e.
An analysis of meteorological The onsite meteorological conditions and atmoapheric measurements prt4 rara should be fully diffusion factors (X/Q) for documented in the safety analysis accidental and annual average report, in a c c o r dance with releases of effluents should be subparagraph 50.34(a)(!) and provided and the assumptions and 50.34(bX1) of 10 CFR Part 50.
l 125 112 23.4
TABLE 1 Extremely Stable (AT exceeds 4.0" C/100m)
Period of Record:
Wind Wind Speed (mph) at 10m Level Direction
_13 4_7 8 12 13-18 19-24
>24 TOTAL N
NNE NE ENE E
WNW NW NNW VA RI ABLE Total Periods of calm (hours)-
Hours of missing data -
125 \\\\3 23.5
TABLE 2 Canification of Atmospheric Stabuity Str.biaty Pamiuta ag' Temperstare change Ocidnestion M
(degrees) with hehht (*C/100m)
Extremely unstable
'A
~
25.0*
< 1.9 Moderately unstable B
20.0*
-1.9 to -1.7 Slightly unstable C
15.0*
1.7 to.l.5 Neutral D
10.0*
.l.5 to 0.5 SUghtly stable E
5.0*
4.5 to 1.5 Moderstely stable F
2.5*
1.5 to 4.0 Extremely stable G
1.7*
>4.0 O
rj
- Standard deviation of horizontalwind direction fluctuation over a period of 15 minutes to I hour. The values shown are everages for each stability classification.
9 23.6 125 114