ML17053A378
| ML17053A378 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 01/08/1979 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Dise D NIAGARA MOHAWK POWER CORP. |
| References | |
| NUDOCS 7901170054 | |
| Download: ML17053A378 (72) | |
Text
Docket No. 50-220 Je8
'ir.'onald P. Disc Vice President - Engineering Niagara Mohawk Power Corporation 300 Erie Boulevard West
- Syracuse, New York 13202 Dear Hr Disc 0
Distribution
,~ocket ORB 103 Local PDR NRC PDR VStello
- BGrimes, Attorney,'ELD OIuE (3)
TIppol ito SSheppard PPolk DEisenhut TERA JRBuchanan
~
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ACRS (16)
By letter dated September 1, 1978, as amended by letters of November 30 and December 13, 1978, you requested approval of the installation of a radwaste reduction system as required by 10 CFR 20.305.
The proposed system is to be inst'alled at the Nine f1ile Point Unit 1 Nuclear Station.
I ~
I In order to continue our review of your proposal, you are requested to provide written responses for the items identified in-Enclosure 1 by February 9, 1979.
In addition; it is our present intention to discuss these items and other items with you during the forthcoming technical meeting in Oswego, New York.
This meeting has been scheduled for January 30, 1979.
In consonance with NUREG-0292, the January meeting will be an open meeting to allow the public an opportunity to observe the NRC review process.
It wilf begin at 1:00 P;N. at the Pontiac Hotel in Oswego, New York.
Following an introduction and presentation of background information by the NRC staff and a facility description by Niagara Mohawk, we will discuss technical. concerns which have been brought to your attention.
After.a break for dinner, the meeting will resume at 7:00 P.H.
The meeting with you is expected to end about. 8:00 P.N. after which time members of the public are invited to ask questions or offer comments to the NRC concerning the review of~pour proposal.
If we can be of further assistance, please advise.
, >>01ZVOOSf.
Enclosure:
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Sincerely, Otd@nni Signed hX
'i'. g. ippolito Thomas A. Ippolito, Chief Operating Reactors Branch 3
Di~ision of Operating Rea tors
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Docket No. 50-220 If we can be of further assistance, please advise.
Sincerely, Distribution Docket ORB ¹3, Local PDR NRXKXXRHX.
NRC PDR VStel.lo, 11 BGrimes
- Attorney, OELD PIr. Donald P. Disc OISE (3)
Vice President - Engineering TIppo1 ito Niagara Mohawk Power Corporation SSheppard
'00 Erie Boulevard West
- Syracuse, Hew York 13202 DEisenhut TERA
Dear tIr. Disc:
JRBuchanan ACRS (16)
By letter dated September 1, 1978, as amended by letters. of November 30 and December 13, 1978, you requested approval of the installation of a radwaste reduction system as required by 10 CFR 20.305.
The proposed system is to be installed at the Nine Nile Point Unit 1 Nuclear Station.
In order to continue our review of your proposal, you are requested to provide written responses for the items identified in Enclosure 1 by February 9, 1979.
In addition, it is our present intention to discuss these items and other items with you during the forthcoming technical meeting in Oswego, Hew York.
This meeting has been scheduled for January 29, 1979.
I, In consonance with HUREG-0292, the January meeting will be an open meeting to allow the public an opportunity to observe and participate in the HRC review process.
It will begin at 1:00 P.H. at the Pontiac Hotel in Oswego, Hew York.
Following an introduction and presentation of background information by the NRC staff and a facility description by Niagara Mohawk, we will discuss technical concerns which have been brought to your attention.
After a break for dinner, the meeting will resume at 7:00 P.H.
The meeting with you is expected to end about 8:00 P.H. after which time members of the public are invited to ask questions or~offer comments to the NRC concerning the review of your proposal.
Thomas A. Ippolito, Chief Operating Reactors Branch ¹3 Division of Operating Re cto s orrlcagn Re CURNAMII~
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Niagara Mohawk Power Corporation CC:
Mr. Herbert Van Schaach Oswego County Building 46 E. Bridge Street
- Oswego, New York 13125 i's. Andria Dravo Subcommittee on Energy and Environment 1327 Longworth Avenue
';.'ashington, D.
C.
20515 Mr. Frank R.
Church Town of Scriba Scriba Municipal Building R.
D. -;2, Creamery Road Box 76
- Oswego, New York 13126 Mr.
Dames
- Best, Chairman R.
D.
7 B-s view Drive
- Fulton, New York 13069 Mir. Thomas C. Elsasser State Liaison Officer U. S. Nuclear Regulatory Corrmission, Region 1
631 Park Avenue King of Prussia, Pennsylvania 19406 Mr. Robert D. Vessels Director, Office of Environmental Planning New York State Public Service Commission New York State Empire Plaza
- Albany, New York 12223 Mr, Thomas Cashman Environmental Conservation Department 50 Wolf Road
- Albany, New York Mr. T.
K. DeBoer Director, Technical Development Programs State of New York Energy Office Agency Building 2 Lmpire State Plaza
- Albany, New York 12223
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<iew York S:ate Energy Office 2 Rockefeller Plaza A<b=ny, l'e':: Yol k 12223
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20036 Anthony Z. Roisman Natural Resources Defense Council 917 15th Street, N. W..
Washington, D.
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20005 Oswego County Office Building 46 E.
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- Oswego, t<ew York 13126
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REQUEST FOR ADDITIONAL INFORMATION TO NIAGARA MOHAWK POllER CORPORATION ON PROPOSED RADWASTE VOLUME REDUCTION SYSTEM AT NINE MILE POINT UNIT 1
NUCLEAR POl<ER PLANT
-r
RADIOLOGICAL ASSESSMENT BRANCH l.
Based on opera'ting experience and on the specific design features of-the Nine Mile Point 1 radwaste handling system, provide an estimate of the annual man-rem associated with each of the following functions; operation, maintenance, and inservice inspection.
Include in your response
- 1) the radia-tion fields (R/hr) associated with all components and cubicles of the radwaste system where personnel may require access to perform the above mentioned functions,
- 2) the occupancy times (hrs/yr) required in each of these locations, and 3) the exposure (man-rems/yr) received for each function and/or location.
Supply this information for all segments of the rad-waste
- system, including the off-gas clean up system, from the inputs to the RWR-1 system to the shipment of solidified wastes offsite.
2.
Describe how the solid waste ash is transferred from the dry cyclone to the product container.
Describe the 'means of regulating the amount of waste ash inserted into each product container.
What features are incorporated to ensure that personnel doses during this operation are maintained ALARA7 3.
Provide the approximate locations of and give the criteria used for placement of radiation monitors in the radwaste drumming and incinerator areas.
r
'~
~e
ACCIDENT ANALYSIS BRANCH 1.
Justify your statement that the maximum credible accident is the gross failure of the product container by discussing radiological consequences and likelihood of other postulated accidents such as gross incinerator failure, failure of piping between incinerator and dry cyclone, failure of piping between dry cyclone and quench
- tank, and the failure of tanks containing radioactive liquids, such as the scrub liquid tank.
2.
For the maximum credible accident as you describe, i.e., gross failure of a product container, explain why a dilution factor (X/g) for an elevated (100 meter) release is appropriate.
What is the radiological impact if a ground-level release is assumed?
3.
The operation of incinerators in the past has resulted in a significant number of explosions.
Discuss the likelihood of an explosion in your incinerator, measures taken (by design or administrative procedures) to prevent explosion, and the radiological consequences of an explosion.
I 4.
Provide layout drawings including expected radiation fields, shielding thicknesses and personnel access routes for the building proposed to house the radwaste reduction system.
AAB-1
/4
Discuss what actions you'e taken in the design of the facility and what action you expect to take during the operation of the facility to assure that occupational radiation exposures will be as low as is reasonably achievable.
Regulatory Guide 8.8 may be used for guidance for activities which may be incorporated to meet this requirement.
RAB-2
HYDROLOGY-METEOROLOGY BRANCH -
METEOROLOGY Q372.2
-In your evaluation of the maximum credible accident, you used the model described in Regulatory Guide 1.3 and assumed an elevated release.
As stated in Regulatory Guide 1.3, the guide's model should be used only until adequate site meteorological data are obtained.
It is our position that you should either (1) provide relative concen-tration (X/Q) values based on site data for both elevated and ground-level releases for the maximum credible accident, or (2) justify that your FSAR or latest assessment of short term diffusion estimates is conservative.
If you undertake to justify your recent assessment, describe the atmospheric dispersion model which you have used to estimate X/Q values. for the maximum credible accident.
(Also see Q.372.3.)
Provide (or reference) the meteorological data that you have used and justify that it is either representative of the air layers into which the effluents will be released or provides for a conservative assessment.
Include a discussion on the marine-air/land-air ransition zone as it relates to the meteorological tower data and the atmospheric diffusion model.
Q372.3 In your response to part 1 of 372.2 above, we suggest you consider DRAFT Regulatory Guide 1.XXX, "Atmospheric Dispersion Models for Potential Accident 'Consequence Assessments at Nuclear Power Plants" (9/23/77), which is attached.
The Draft describes a procedure for calculating short-term relative concentration (X/Q) values.
This method considers
- 1) lateral plume meander;
- 2) atmospheric dispersion conditions as a function of direction;
- 3) wind direction frequencies; and 4)
HMB-1
exclusion area boundary distances as a function of direction.
Also enclosed is, an interim branch technical position concerning the use of the Draft and the model described in Standard Review Plan 2.3.4.
9372.4 For any effluent particulate matter with an effective deposition velocity greater than five centimeters/second, provide the effective deposition velocity.
HUB-2
I
HYDROLOGY-METEOROLOGY BRANCH It is our position that either the draft Regulatory Guide 1.XXX, "Atmospheric Dispersion Models for Potential Accident Consequence Assessments at Nuclear Power Plants" (dated September 23, 1977), or the procedures described in Standard Review Plan Section 2.3.4 may be used to evaluate atmospheric transport conditions for analysis of accidents with the following amend-ments to the draft regulatory guide model:
(a) a limiting sector X/9 value at the 0.55 probability level be used*,
(b) the accumulated frequency of the limiting sector X/g or higher value in all sectors may not exceed 5/ for the site, and; (c) normalization of individual sector probability distributions is not used.
~Amendment based on Memorandum from H.
R. Denton to D.
R. Muller,
Subject:
Proposed New Meteorological Model, dated August 2, 1978.
l
$fP 8 3 577 REGULATORY GUIDE 1.XXX ATMOSPHERIC DISPERSION MODELS POR POTENTIAL ACCIDENT CONSEQUENCE ASSESSMENTS AT NUCLEAR POWER PLANTS A-INTRODUCTION Section 50.34 of 10 CFR Part 50 requires that each applicant for a construction ermit or p
'perating license provide an analysi.s and evaluation of the desi n and erfo
'g p
rmance of structures, systems and components of the facxlity with the objective of assessing the risk to public health and safety resulting from the operation of the facility.
Section 50.34 of 10 CPR Part, 50 further states that the site evaluation factors identified in 10 CFR Part, 100 shall be included in the analysis and evaluation described above.
Section 100.10 of 10 CZR Part 50 states that meteoro-lo ical condit' itious at the site and surrounding area are to be included in the factors to be considered xn assessing the consequences of potential reactor accidents.
This guide provides acceptable procedures and assumptions that may be used to determine appropriate atmospheric dispersion conditions for assessing the consequences of potential nuclear power plant reactor accidents which are made as required by Section 100.11 of 10 CER Part 50.
The Regulatory Position presented in this guide represents a substan-teal change in procedures used to determine atmospheric dispersion condi-talons appropriate for use in assessing the potential offsite radiological
MEFf consequences resulting from a range of postulated accidental releases of radiological material to the atmosphere.
This guide provides an acceptable methodology for determining site specific relative concentrations (QQ) and replaces portions of Regulatory Guide 1.3, Revision 2, "Assumptions. Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Boiling Water Reactors," Regulatory Guide 1.4, Revision 2, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Pressurized Water Reactors,"
Regulatory Guide 1.5, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Steam Line Break Accident for Boiling Water Reactors," Regulatory Guide 1.24, "Assumptions Used for Evaluating the Potential Consequences of a Pressurized Water Reactor Radioactive Gas Storage Tank Failure," Regulatory Guide 1.25, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Fuel Handling Accident in the Fuel Handling and Storage Facility for Boiling and Pressurized Water Reactors,"
Regulatory Guide 1.77, "Assump-tions Used for Evaluating a Control Rod Ejection Accident for Pressurized Water Reactors,"
and Regulatory Guide 1.98, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Radioactive Offgas System Failure in a Boiling Water Reactor."
B.
DISCUSSION The procedural changes contained in this guide are based on a review of recent experimental data on diffusion from ground-level releases without buildings present and from releases at various locations on reactor facility 1.XXX-2
r
buildings during stable atmospheric conditions with light wind speeds (Refs. 1-6), and a recognition that meteorological evaluation procedures should provide estimates of the variations in atmospheric dispersion that occur as a function of wind direction and distance from the source to receptor.
The procedures described in this guide incorporate the results of the atmospheric tests referred to above which verify the existence of effluent plume "meander" under stable (E, F and G) atmospheric conditions, as defined by the M criteria in Regulatory Guide 1.23 (Ref. 7), when wind speeds are light.
Effluent concentrations measured over a period of one hour under such conditions have been shown to be substantially lower than would be predicted using the traditional curves (Ref. 8) of lateral and vertical plume spread, based upon current atmospheric stability criteria.
The procedures in this guide also recognize that atmospheric dispersion con-ditions are frequently dircctionally dependent; that is, certain air flow directions can exhibit substantially more or less favorable diffusion conditions than others, and the wind can transport effluents in certain directions more frequently than in others.
C.
REGUIATORY POSETION This section identifies the atmospheric transport and diffusion models, methods of evaluating boundary distances for the exclusion area and the outer boundary of the low population zone for purposes of estimating disper-sion values, and the methods of establishing gQ value distributions and selecting gQ values to be used in consequence assessments that are accept-able to the NRC staff.
1.XXX-3
l
1.
Calculation of Relative Atmos heric Concentration x/
Values X/Q values should be calculated at appropiiate distances (see C.2 below) for each wind direction (16 compass points; 22-1/2 degree sectors centered on true north, etc.) based on wind speed and atmospheric stability class indicated by vertical temperature gradient (dT), as defined in Regula-tory Guide 1.23 for distances to 80 hn (SO mi) from the site.
Either hourly averaged data or joint frequency distributions of hourly data may'e a
used.
When joint frequency distributions are used, the wind speed for X/Q calculations should be the maximum value in the wind speed class interval so that the individual X/Q values are calcu)ated to represent the minimum value in the cumulative frequency class interval.
The distribution is then enveloped by the maximal X/Q values.
- Thus, when the cumulative probability distributions of X/Q are assessed, each X/Q value represents that which is 1
equaled or exceeded within the class interval (Ref. 9).
When hourly data are used, the wind speed for X/Q calculation should be the "hourly averaged" wind speed as defined in Regulatory Guide 1.23.
Calms should be defined as hourly average wind speeds below the starting speed of the anemometer, and should be assigned a wind speed equal to that of the anemometer or vane starting speed, whichever is higher.
When joint frequency distributions are used, wind directions during calm conditions should be assigned in proportion to the directional distribution of the lowest non-calm wind speed class.
When hourly data are used, wind directions during calm condi-tions should be assigned in proportion to the directional distribution of non"calm conditions with a wind speed less than 0.7 meters per second (m/s)
(the wind speed class limit, i.e., 1.5 mph).
1.XXX 4
Formulae and parameters presented in this section should be used in the absence of site specific diffusion data unless unusual siting, meteoro-1o8ical or terrain conditions dictate the use of other models or considera-tions.
For example, quality controlled, site-specific atmospheric diffusion tests may be used as a basis for modifying the formulae and parameters.
a.
Short-term (( 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) release period calculations Acceptable mathematical models for calculating X/Q values appro-priate for short time period atmospheric dispersion calculations are presented below.
Meteorological data and calculations for the one hour time period are assumed to apply over the entire two hour release period.
This assumption has been confirmed as reasonably conservative, considering the variation with time of postulated accidental releases.
If releases associated with a given postulated event are estimated to occur in a period, substantially less than one hour (i.e., less than 20 minutes),
the applicability.of the models should be evaluated on a case-by-case basis.
(1)
Releases through vents or other building penetrations This class of release modes includes all release points or areas which are lower than two and one half times the height of adjacent solid structures (Ref. 10).
The formulae and assumptions are:
(a)
During conditions of neutral (D) and stable (E, F and G) stability when the speed at the 10 meter level is less than 6 m/s, credit for horizontal plume meander can be considered such that u10 ill 0 1.XXX-5
I
whenever the X/g value, calculated using Equation 1, is less than the greater value calculated from either u10 (n cr cr
+ A/2) y z or 1
u10 (3na e)
Z (3) where is the relative concentration (sec/m
) at ground level, 3
n is 3.14159, 10 is the wind speed (m/s) at 10 meters above grade, is the lateral plume spread (m),
a function of atmospheric stability, wind speed u10 and downwind distance from release.
For distances to &00 meters, E
= McF; M being a function of atmospheric stability and wind speed (see Figure 3).
For distances greater than 800 meters, X
= (M-1)< g00
+
y y
is the lateral plume spread (m),
a function of atmospheric stability and distance (Figure 1),
1.XXX-6
'I
is the vertical plume spread (m),
a function of atmospheric stability and distance (Figure 2), and A
is the smallest vertical plane, cross-sectional area (m } of the building from which the effluent is released.
Otherwise X/g is the greater value calculated from either Equation 2 or 3.
In other words, calculate X/g values based on Equations 1,
2, and 3.
Compare the values computed from Equations 2 and 3, and select the higher value.
Compare this higher value with the value calculated through use of Equation 1, and select the lower of these two values to represent the X/g value for postulated release and atmospheric conditions.
Examples and a detailed explanation of the rationale are given in Appendix A.
(b)
Ouring all other atmospheric stability and/or wind speed conditions, X/g is the greater value calculated from either Equa-tion 2 or 3.
(2)
Stack Releases A stack release is assumed when the effluent is exhausted from a release point that is higher than two and one half times the height of adjacent solid structures (Ref. 10).
The general formula and assumptions are:
where nuhc c
y z
exp
-he ZAJ2 is the wind speed (m/s} which represents conditions at the release
- height,
I
h is the effective height (m) determined from h
= h
- h e
s t'
is the height of the release point above plant grade, and h
is the maximum terrain height above plant grade between the release point and the point for which the calculation is made, but should not be a11owed to exceed h
s The other parameters in Equation 4 have been defined previously.
Atmospheric stability for determination of (r and a is obtained from the vertical temperature differences (hT) between the release height and the 10-meter level as described in Regulatory Guide 1.23.
For those cases where fumigation conditions are to be evaluated for elevated
- releases, the formula and assumptions are:
(2n) u a h
y e
where is wind speed (m/s) representative of the layer h
for e'hich a value of 2 m/s is a reasonably conservative assumption in most, cases, cJ is the lateral pLume spread (m) at a given distance which is usually assumed for a moderateLy stable (F) atmospheric stability condition which normally precedes the onset of-fumigation, and
P
h is as defined above for elevated releases.
e 1
The QQ value calculated by Equation 5 should not exceed Ãucf c b.
Release eriods reater than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> The average QQ values should be calculated for appropriate time periods during the course of the postulated accident as described below.
The time periods for averaging should represent intra-diurnal, diurnal and synoptic meteorological regimes (e.g.,
8 and 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and 3 and 26 days as presented in Section 2.3.4 of Regulatory Guide 1.70)
(Ref. 11).
The +Q value for each appropriate time period at the distance of interest in each direction sector should be obtained by a logarithmic interpolation between the calculated value that is selected using the procedure described in Section.C.3.a below,. assumed as a "2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />" value, and the annual average (8760 hour0.101 days <br />2.433 hours <br />0.0145 weeks <br />0.00333 months <br />) value at the distance of interest in that direction sector (Ref. 9).
The annual average gQ value should be calculated using the method described in Regulatory Guide 1.111, Section C.l.c. (Ref. 12), but with h determined as described in Section C.l.a.(2) above.
e 2.
Determination of Distances for X/
Calculations En order to take into consideration the possibility of airflow trajec-tory deviations, plume segmentation (particularly in light wind, stable conditions),
and the potential for wind speed and direction frequency shifts from year to year, the following procedure should be used to determine the distance from which the calculations of relative concen-trations (QQ) are made.
1.XXX-9
MEFf For each wind direction sector, the minimum distance (exclusion area or LPZ) to be assumed for the sector of interest should be defined as the minimum distance within that sector and one-half of the width of the direction sector on either side of the sector of interest.
EffectiveIy>
this distance is the minimum distance of either the exclusion area or LPZ within a 45 degree direction sector, centered on the direction sector of interest.
- However, should there not be a well defined exclusion boundary'n a sector (e.g.,
a sector extending seaward at a coastal site) then the distance for that sector should be taken as that distance over which the applicant or licensee intends to have control.
3.
Determination of Q Values b
Sector a.
Assessment of / 's at the exclusion distance Acceptable procedures for selecting the X/Q values to be used in the consequence assessment analyses for both the "conservative" and "realistic".
accident conditions (see Section 2.3.4 of Ref.
- 11) are described below.
For the realistic assessment, fumigation conditions may be ignored.
(1)
Non-fumigation conditions Cumulative probability distributions of the QQ values, as determined from Section C.l.a above at the distances determined from Section C.2 above, excluding fumigation from elevated
- releases, should be constructed f'r each of the 16 cardinal compass point directions (22-1/2 degree direction sectors).
Each directional probability distribution should be normalized to 100$. If joint frequency table data are used to calculate the QQ values, the cumulative probability distribution function should be computed such as to envelope the data points.
X.XXX-10
I
(P ) for the selection of the X Q The effective probability level or ined (Ref
- 9) by first, value in each dizection sector should be determine selected as 5~ for the conservative multiplying the probability level (P),
se ec e
a
'o of the total number of hours (N) having accident assessment, by the ratio o t e o
olo ical data record (1 year =
valid wind and stability data in the meteoro ogi n
in which the wind flow was 8760 hours0.101 days <br />2.433 hours <br />0.0145 weeks <br />0.00333 months <br />) to the number of those hours (n) in i
and then dividing this product by into the direction sector of interest, an sectors of 22~q degrees).
For the the total number of sectors (S)
{16 for sec or ination as described in Section realistic accident assessment QQ determina i P should be selected as 50~.
2.3.4 of Regulatory Guide l.70 (Ref. 11),
s This procedure, in equation form may ma be stated as:
P (N/n)
(6) he e uation aze described as above.
lt.
where the individual terms xn t~e equa eed 100~ if n is sufficiently small.
ln should be noted that P
can excee a XI Q value may be ignored unless the those directions, the selection of a XI va high when compared with yJQ values at QQ values for that sector are very hi~ w e P
in other direction sectors.
XI'Q values that are selected, as described For each assessment, the d and the highest value is selected.
above, for the 16 directions are compared and e
g
{2)
Fumigation conditions - conservati ative assessment In the absence of information which i h indicates that fumigation 11 less than five percent of the time, XIQ conditions occur substantially ess a
fumi ation conditions, for each of values should be calculated, assuming umig the 16 directions sectors using Equation
I
(a)
Inland sites For elevated releases at sites located at distances equal to or greater than 3200 meters from large bodies of water (e.g.,
oceans or a Great Lake),
a fumigation condition at the exclusion distance should be assumed to exist. at the time of the accident and continue for one-half hour (Ref. 13).
In this case, two gQ values, one for the 0 to 1/2-hour time period and the other for the 1/2 to 2-hour time period following the accident, should be selected for the accident consequence analysis using the following procedures.
For the 0 to 1/2-hour time period QQ values should be determined, using Equation 5 for sectors in which the effective height. of release (h ) is greater than 0, or using Equation 4 and the selection e
procedure described in Section C.3.a.(l) above for sectors in which h
= 0 for each of'he 16 direction sectors.
For the 1/2 to 2-hour time period, gQ values for each of the 16 direction sectors should be determined using Equation 4 and the selection procedure described in Section C.3.a.(1) above.
(b)
Coastal sites For elevated releases at sites located less than 3200 meters from large bodies of water, a fumigation condition at the exclusion distance should be assumed to exist at the time of the accident and continue for four hours (Ref.
- 13) in each of the onshore and along shore airflow directions.
The QQ value to be used in the accident consequence analysis for the 0 to 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> period following an accident, in this case, is the maximum of the 16 individual direction sector gQ values, calculated and selected as described 1.XXX-12
I I
efore ~ two hour X/Q va lues above foz the 0 to 1/2-hour time period.
There ore, hould be based entirely on fumigi ation conditions.
for exclusion distances s ou on s not consider frequency and duration onservative assessment.
does not const er QLT,8 C
unction of air ow zr uncti
'l d
ection. If information of fumigation conditions as a functi e actual directional occurzence can be presented to substantiate the ac ua ite the assumptions of and duration o
umiga i f f t on conditions at a site, ctions and of duration of one-half hour fumigation in all appropriate directions an o
ur d'fied.
Then fumigation need only be considered'nd Sour hours may be modi xe Therefore, x
1 d d from consideration of fumigi ation conditions, and directions can be exc u e would still be considered as one half hour.
On the duration of fumigation would sti the ot er an n
non-coastal) may show no directional the other hand, sites in open terzain (non-coas a
ut, ma show durations much less than ezence foz fumigation conditions, but, may s
ow pref one half hour.
n is I
th case fumigation shoul d be considered for all an one-half hour.
directions, ut. wi b
th durations much less than I
Z b.
Assessments of X/
s at the LP tin the X/Q values to be used in Acceptable procedures for selecting e
i ation has been determined will occur for airflow directions in which fumigation as ee e stud For example, examination and of a duration determined from the stu y.
at a location in 1
'n a pronounced river valley may of site-specific information occur zedominatly during the down-valley indicate that fumigation conditions occur pre omina or durations of about one-half hour.
- "drainage flow" regime and persist for durations o
n this case aiz ow x,rec fl d'ions other than the down-valley are desczibed below.
the consequence assessments ar t ~Q values for the appropriate time In most cases, the highest e 22-1/2 degree direction sector.
periods will all. occur within the sane
1 I
(1)
The 16 sets of X/Q values obtained by us' usin the interpola-ared and the in Section C.l.b above should be compar t'on procedure described in Section a
desczibed
- above, should be consi descry e
a dered values for the sector, evaluated as descry e
a ma be used for o
b th the conservative and controlling.
This procedure may
...8@Fr hest X/Q values for the van.ous for those sites at which the hig est However, for ose e same an evalua-e same direction sector, an eva eziods do not all occuz within the same time per o s o
oten ia made for each-otential accident should be ma e
o f the consequences of the poten ia tion o e
or or e
ccident or for the course of the ace@
sector using t e h
X/Q values in that sector or e
ector which produces the greatest analysis.
e Th X/Q values, for that sector w ic t
o e '..
hi hest t
of the public (i.e., the hig es potentia res 1
k to the health and safety o
e h ld be considered controlling.
dose estimate),
s ou on"fumigation conditions realistic accident assessments.
s - conservative assessment (2)
Fumigation conditions - co ites located at distances equal to For elevated releases at sites oca e
e bodies of water, the X/Q value for or greater than 3200 meters from large bo ies r and 1/2 to 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> time the LPZ for the 0 to 1/2 hour an each sector, at t e hould be determined as describ'bed for this periods following the accident shou e
e case in Section C.3.a.(2) above.
tes located less than 3200 meters elevated releases at sites locate e
For Z
for e
Q value or f
each sectoz, at the LP, f fzom large bodies of water, th h
ld be evaluated as described the 0 to 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> period following n
an accident.
s ou for this case in Section C.3.a..,2. above.
1
D.
IMPLEMENTATION to rovide information to app licants The purpose of this section xs o pr regaxding t e s
h
?BC taff's plans for using thi g
's re ulatory guide.
'ce acce ted by the Commission.
This guide reflects current practice accep the a
licant proposes an accept t e a i
table alternative Except in those cases in which t e app i method for complying with specified poxtions o
e e used in the evaluation of submittals e method descxibed herein will be used xn e
e it a lications docketed after for operating ice 1 cense or construction permit app i will be considered for licensing The method described herein wx e
0 reactors on an individual basis.
If an applx-actions concerning operating reactors on an i ato uide in developing submittals for cant wishes to use this regulatory gui e in it a lications docketed on or before operating i license or constxuction permxt app i of the application will be evaluated
, the pertinent portions o
on the basis of this guide.
Date 4 months after publication for public comment.
I I
S'
REFERENCES MAFT of Field Measurements of Atmospheric l.
Vaa der Hoven, E., " A Survey o
xe ion Conditions," Nuclear Safety, Diffusion Under Los-Mind Speed Inversion on
'arch-April 1976', Vol. 17 No. 4.
2.
- Start, e
, 0 E
t al.
"Rancho Seco ux xng B
ld Wake Effects On Atmospheric ARL-XX {in draft), Air Diffusioa," NOAA Technical Memorandum ERL ARL-XX {*
a ls
- Idaho, 1977, available from Publi-Resources Laboratory, Idaho Falls, a o, arch Laboratories, National Oceanic cation Services, Environmental Researc a
o aad Atmospheric Administration, Boulder Colorado 80302.
1 "Diffusion Uader Low Wxndspee ed Conditions Near 3.
- Wilson, Re Boy et a
~
ARL-61 Air Oak Ridge, Tennessee, " NOAA Technical Memorandum ERL ARL s
- Idaho, 1976, available from Publi-Resources Laboratory, Edaho Falls, a o, search Laboratories, National Oceanic catioa Services, Environmental Researc a or and Atmospheric Administration, Boulder Colorado 80302.
on "Diffusioa Under Los Wiadspeed, 4.
Sagendorf, J. Z. and C. R. Dickson, i
ARL-52, Air Eaversion Conditions, " NOAA Technical Memorandum ERL ARL s
Edaho 1974, available from Resources Laboratory, Edaho Falls, a o, eatal Research Laboratories, Natioaal Publication Services, Environmental esear Boulder, Colorado 80302.
Oceanic and Atmospheric Administration; o
OHIO REFERENCES (Cont'd.)
3.
Gulf States Utilities Company, "Dispersion of Tracer Gas at the Proposed River Bend Nuclear Power Station," Preliminary Safety Analysis Report, Amendment 24, Docket Numbers 50-458 and 50-459, 1974 6.
Metropolitan Edison Company, Atmospheric Diffusion Experiments with SF Tracer Gas at Three Mile Island Nuclear Station Under Low Mind 6
Speed Inversion Conditions," Final Safety Analysis Report.,
Amendment 24, Docket Number 50-289, 1972 7.
Regulatory Guide 1.23 (Safety Guide 23), "Onsite Meteorological Programs,"
U.S. Nuclear Regulat'ory Commission, Washington, D.C.
8.
Gifford, F. A., Jr.,
"An Outline of Theories of Diffusion in the Iower Layers of the Atmosphere,"
Chapter 3 in Meteorolo and Atomic Ener 1968 (D. H. Slade, Ed), available as TID-24190 from the National Technical Information Service, Springfield, VA 22151.
9.
Markee, E. H., Jr.
and J.
R. Levine, "Probabilistic Evaluations of Atmospheric Diffusion Conditions for Nuclear Facility Design and Siting," Paper in Proceedings of the American Meteorolo ical Societ Conference on Probabilit and Statistics in Atmos hezic Sciences, Las Ve as Neveda November 1977. (in draft)
~
1
REFERENCES (Cont'd.
8<AT 10
- Synder, V. H. and R. E. Lawson, Zr., "Determination of a Necessary ft Height for a Stack Close To A Building"A Wind Tunnel Study, Atmos heric Environment, Vol. 10, pp 3-g 683-691 Per amon Press, 1976 ll.
Regulatory ui e G 'd 1 70 "Standard Format and Content of Safety Analysxs Reports for uc ear ower f
N 1
P w r Plants - LWR Edition," U.S. Nuclear Regulatory Commission, Washington, D.C.
12.
Regulatory Guide e
o 1 ill "N thods for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releas g
es from Li ht-Water-Cooled Reactors,"
U.S. Nuclear Regulatory Commission, Was~xngton, D.C.
13 Van der Hoven, T., "Atmospheric Transport and Diffusion at Coastal Sites," Nuclear Safet
, Vol. 8, pp 490-499, 1967
C I
4
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t t
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i i ~ill
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A EITREhlEI.Y UNST281.E s:
~
~
~
~'
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8 MOC RATELY UNS A8t, C
51 IOHTLY UNSTABLE NEUTRAt E
SLIOt!TLY STA8LE P - MOOERaTELY STa8LE IO I
~
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~
~ I I
I I
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I !!
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~
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~
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4a lo0 10
~
I I I
I
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s lo a
s 10 a
s lo QISTANCE FROM SOURCE I!tll Hyxx'e 1.
Lateral dC uskon, cr, vs. downwind Q.stance zola y
source for Pasquil's tuzbulence types (Ref. 8).
<oz purposes of est mtfag ITy during extremely stable (Q) conditions, without plune meander or other lateral enhancement, the follov~mg appzo~at'on is appzopz~mte:
ITy (6)
~2 ey (7)
'I I
II
DRAFT Jato Io 6
2 W
I7 la<~ lo IJ O
W 0
IO O
2 W
IO I
I I Ill
~ I I
Ir(
l I
I I I!
I I
I I I I l I
I I
EXT RE!IIEIY I'tl5TASI.E 5
MCCERATEIY VII5TAbt.E s
C St IGIITCYQlc5TASI E 0- NEVTRAI.
E 5I.IGIITIY 5 A6I.E r- ~4OERATEI.Y STaet.El I
I
~
I I
~
I I II I
~
I
~ l 1111111 Io Ioi 2
5 IOA 2
5 10 2
OISTAIICK FROIII 54VRCE Ifttl 5
lo'1guze 2
Vertical 4&fusioa, cr, vs. Coen~ distaace froth source for Pasq~'s turbulence t7pes (Ref 8).
Por purposes of est~ting er during extrmIKLy stable (C) coadktioas, the follcnrLng approxfmt" oa f.s appropriate:
cT<(C)
> ITr g')
E.XZX-ZO
C
10 cc 3
O CD 2
1 1
2 3
4 5
6 QZKI SPEED (ta/sec)
Pfgxre 3.
Correction factors for Pasquf3.1Mifford o
values.
(Basecf on analyses of Ref..2) 1 XXX 21
C
APPENDIX A ATMOSPHERIC DIFFUSION MODEL FOR RELEASES THROUGH VENTS AND BUIlDING PENETRATIONS
,Rationale The effects of building wake mixing and ambient plume meander on atmos-pheric dispersion is expressed in this guide in terms of conditional use of Equations 1,
2 and 3.
Equation 1 is an empirical formulation based on atmospheric diffusion experiment results (Reference
- 2) and includes the combined effects of increased plume meander and of building wake in the horizontal crosswind direction over time periods of one hour when the wind speed is light.
Although the results could not be quantified, these experi-ments also indicate that vertical building wake mixing is not as complete during light wind, stable atmospheric conditions as during moderate wind, unstable conditions.
Equations 2 and 3 are formulations which have had widespread acceptance within the meteorological community over a period of many years (Ref. 8), but have been recently found to provide estimates which are too conservative at least for the light wind, stable atmospheric conditions (Ref.
1 and 2).
Therefore, based on the principles that horizon-tal plume meander dominates dispersion during light wind, stable conditions and that meander diminishes as the wind speed increases and the atmospheric stability decreases while building wake mixing becomes more effective in dilution of effluents, the conditional use of Equations 1,
2 and 3 is appropriate for providing reasonable QQ estimates.
A 1'
c
(>
Zxamale Whee Figure A-1 shows plots of X/Q times the wind speed u
versus downwind 10 distance for Equations 1,
2 and 3 for atmospheric stability class G.
Equation 1 is plotted for M = 2, 3 and 6.
Figure A-2 shows plots of X/Q times u10 versus downwind distance based on the conditional use of Equations 1,
2 and 3 as described in the Regulatory Position for wind speed conditions appropriate for M = 2, 3 and 6.
Comparison of Figure A-1 to Figure A-2 shows that for M = 6, Equation 1 is used for all distances since the y u
/Q 10 for Equation 1 is less than the values calculated for the greater value produced by either Equation 2 or Equation 3 at all distances.
For M = 3, the values from Equation 1 are used for distances beyond 0.8 km since the greater value produced by either Equation 2 or Equation 3 is greater than the value produced by Equation l.
However, for distances less than 0,8 km, Equation 1 equals Equation 3.
Therefore, the appropriate X/Q value is determined from Equation 3 since Equation 1 is not less than Equation 3, and Equation 3 produces the higher value when compared with Equation 2.
Men M = 2, Equation 1 will not be used at all since it is never less than the greater value produced by either Equation 2 or Equation 3.
- Instead, Equation 3 will be used up to 0.8 km and Equation 2 will be used beyond 0.8
10-2 Eq.1, M 3 Eq.l, M 6 10 Eq.2 Eqe l, M~3 Kq. 1, N 6 Eq3 0.1 1.0 PLUME. TRAVEL. OISTANCE (K$1ometers) 10
~<8 <e + l X UgplQ as a function of plume travel distance fog Q stab11i.ty cond'.tion usia'quations l, 2 and 3 ~
'I
M~2 M 3 10
~
0.1 1.0 20 PLUME TRAYEL OlSTANCE (K<1ometers)
Figure A-2.
Regu1atory Posftfon on x 610/g as a function of plume trave1 Nstance for G stabf1$ ty cond$ t$on.
h-4
1'