ML20030A532
| ML20030A532 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 11/01/1976 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8101090954 | |
| Download: ML20030A532 (6) | |
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November 1, 1976 N;
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Director of Nuclear Reactor Regulation T
Att: Mr Dennis L Ziemann, Chief 7.;,
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j'-vg Operating Reactors, Branch No 2 US Nuclear Regulatory Cor:: mission s s N l l' Y rs i Washington, DC 20555 DOCKET 50-155, LICENSE DPR BIG ROCK POINT PLANT Transmitted attached are answers to question No 1 of your letter of September 3, 1976 and to questions No 1 through 3 of your letter dated September 2h,1976.
These questions were related to the requirements of Appendix I to 10 CFR 50 for the Big Rock Point Plant.
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QUESTIONS FROM SEPTE!GER 3 LETTER Request for Additional Information Big Rock Point Nuclear Station Docket No 50-155 1.
Provide the relative temperature difference between exhaust effluent and ambient air for the gaseous radvaste effluent release point (plant stack) and indicate if it is equipped with diffusers or spreaders.
ANSWER: Stack exhaust temperatures nave been measured only during special tests. Two such tests performed within the past 13 months indicated a relative temperature differer.ce of 38.5 F with the plant at 83% power (daily mean stack gas 97 5 F, daily mean outside air 59 F) and a relative temperature difference of 16*F during an outage,mean stack gas 61 F, outside air 45 F).
The stack is not equipped with diffusers or spreaders.
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QUESTIONS FROM SEPTE!SER 214 LETTER REQUEST FOR ADDITIONAL INFORMATION BIG ROCK POINT NUCLEAR STATION _
DOCKET NO 50-155 1
1.
Based on examination of-the results of the meteorological studies performed at the Big Rock Point site, it appears that measurements
' from the 256-foot meteorological tower may be representative of at-mospheric transport and diffusion conditions only at the lake shore-line, especially during onshore vind conditions. Although these data may represent the conditions into which gaseous effluents are released from the stack, they may not be representative of atmospheric transport and diffusion characteristics further inland (eg, at or beyond the site
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boundary). Provide the following information:
Indicate whether calculated relative concentration (X/Q) and rela-a.
tive deposition (D/Q) values at various inland receptor locations based on measurements from the 256-foot tower could be substen-tially underestimated.
ANSWER: The 50-foot to 250-foot AT and vind data that were used to
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classify atmospheric stability and transport conditions are considered to be representative of the portion of the atmosphere into which the 2h0-foot stack emits effluents. Due to the proximity of the Big Rock Point Nuclear Station to Lake Michigan, stable onshore gradient flow or lake breeze circulations can be significant due to inversicn con-ditions that may.be associated with them. During these conditions, the stable layer vould be expected to be modified to more unstable condi-tions farther _ inland due to the greater surface roughness and greater surface heating produced by the land surface, such that the tower data near the shoreline is expected to underestimate downwind atmospheric dispersion. On-site data support this conclusion and show that the thermal internal boundary layer exists predominantly below the 50-foot temperature sensor of the meteorological tower. Thus, use of the 50-foot to 250-foot cT results in conservative X/Q relative to ground level conditions.
Further, smoke-plume photography studies conducted by the University of 191chigan scientists at Big Rock Point confirm that for diffusion of a plume overland, various atmospheric mechanisms (such as crossvind shear and the characteristics of roughness and heat-ing discussed above) act to enhance atmospheric diffusion especially under stable atmospheric conditions. Therefore, measurements from the 256-foot tower tend to cause substantial overestimat' ion rather than underestimation of concentrations at inland locations.
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(1)E W Hewson, G C Gill and G J Walke, " Meteorological Study of the National Ventilation in the Atmospheric, Big Rock Point Nuclear Plant, Charlevoix, Mlchigan (Final Report)," University of Michigan, College of Enginee"ing, December 1963
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2-b.
Discuss possible modifications to the available data to more ade-quately describe transport and diffusion conditions at and beyond the inland site boundaries.
ANSWER: As stated above, use of data from the 256-foot tower would tend to overestimate concentrations at inland locations. This, coupled with the visual plume observations.which extended well beyond the maxi-mum impact-location for the critical dose pathway (iodine-cow milk, less than 2-1/h niles from the site), shows that previously submitted X/Q and D/Q values are conservative and may be used without modification.
2.
Explain why the two-year period (February 1961 - February 1963) consti-tutes the best available meteorological data, especially considering that these data are over thirteen years old.
Discuss any meteorological data collected at the site since May 1963 and indicate if these data have exhibited any characteristics that could result in significant variations of calculated X/Q and D/Q values based on tha 1961 - 1963 data.
ANSWER: The two-year period constitutes the best available meteorologi-cal data bgcquse of its comprehensiveness (see program description in 1
- Reference \\ll), verification (plume photography study) and scientific rigor.
In addition, it constitutes the only available on-site data.
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The data have been determined representative by comparison with hourly average wind data from Traverse City (see Figures 6.1 and 6.2 of our June 4,1976 submittal) both for the same period and a random seven-year period.
Comparison of these data with 30-year trend records con-firms their applicability to long-term conditions.
For example, the average temperature at Traverse City NWS Station for the 1961-62 period is kh.2 F, while the 30-year average temperature is hh.8 F.
Similarly, the average annual precipitations are 30.h and 29 5 inches, respectively.
(Reference US Department of Commerce, NOAA, Climatological Summary, Traverse City,' Michigan, 1971).
3.
The 256-foot on-site meteorological tower has not been installed since May 1963 Provide the following information:
a.
The rationale for discontinuing measurements from the tower and the date that tower operation was discontinued.
ANSWER: There was not, nor is there now, any legal requirements or public health consideration which suggest that the preoperational meteorological program should be continued. This, the high costs associated with an on-site monitoring program and the aviation hazard presented by the tower, resulted in discontinuation of the program in May 1963 and subsequent removal of the tower structure.
b.
Describe the on-site meteorological measurements program in op-
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eration since May 1963, and compare this program to the recom-
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mendations and intent of Regulatory Guide 1.23 I
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k-3 ANSWER: There has been no formal meteorological monitoring program in operation since May 1963 Discuss proposals for upgrading the on-site meteorological measure-
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ments program to collect representative meteorological data for assessing gaseous effluent releases. Compare these proposals with the r<tcommendations and intent of Regulatory Guide 1.23
. ANSWER: Consumers Power Company has no existing plans for installa-
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tion of a meteorological monitorieg system. The preoperational pro-gram has provided representative neteorological data and is fully adequate for. assessing gaseous effluent releases. In addition, Consumers Power believes the Ccriaission has clearly indicated that only cost-effective backfitting should be undertaken for the purpose of complying with 10CFR50, Appendix I.
The installation of a meteor-ological systes is not. cost effective. The installation of a meteor-ological system would not, in any way, reduce the already small actual dose to the public that' results from the operation of the Big Rock Point Plant.
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NRCecRM 195 U.O. NUCLE AM REGULATORY CO*AMISSCN DOC KE T NUMIE R 52 *
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NRC DISTRIBUTION FOR PART 50 DOCKET MATERIAL FROM:
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DESCIIPTION ENCLOSU RE Ltr re Our 9-3-76 Itr...trans the follow:
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