ML063450128
| ML063450128 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Mcguire, Catawba, McGuire  |
| Issue date: | 12/04/2006 |
| From: | Dolan B J Duke Energy Carolinas, Duke Power Co |
| To: | NRC/ADM/DAS/RDB |
| References | |
| 71FR55517 00017, DG-1164, RG-1.023 | |
| Download: ML063450128 (8) | |
Text
Duke EnergyBryan J. Dolan VP -Nuclear Plant Development 526 South Church Street MailCode:
EC05R Charlotte, NC 28202 704 382 0605 704 382 4545R December 4, 2006 Rules and Directives Branch Division of Administrative Services, Office of Administration U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
-71 F,0 2S 5 I 7
Subject:
Comments on Draft Regulatory Guide, DG-1 164, "Meteorological Monitoring Programs for Nuclear Power Plants" Duke Power Company LLC d/b/a Duke Energy Carolinas, LLC (Duke) offers the attached comments relative to the solicitation for public comments regarding Draft Regulatory Guide, DG-1 164, (Third Proposed Revision 1 of Regulatory Guide 1.23 (Safety Guide 23), dated February 1972), "Meteorological Monitoring Programs for Nuclear Power Plants." Please address any questions to Peter Hastings at (980) 373-7820.Duke appreciates the opportunity to provide these comments.Sincerely, Bryan J. Dolan Vice President Nuclear Plant Development
'jiTI Attachment 1:31 C/)Teb-vIoL) geie &yle- 6 Sli .&Clocr (sco jT-. ter. ki OiT Y)(ww. duke-energy.com U. S. Nuclear Regulatory Commission December 4, 2006 Attachment Duke Energy Carolinas, LLC Comments on Draft Regulatory Guide DG-1 164 (October 2006)Third Proposed Revision 1 of Regulatory Guide 1.23 (Safety Guide 23),"Meteorological Monitoring Programs for Nuclear Power Plants" Item DG-1 164 Topic Comment page and section Page 10 System The system accuracy specification for vertical temperature Table 2 Accuracy of difference (delta-T) is +/- 0.10 C. However, the system Section 4 Vertical accuracy of the temperature probes used to determine the Temperature temperature difference is only +/- 0.5 0 C.Difference Thus, the accuracy of +/- 0.1' C for delta-T cannot be met. In and order to meet an accuracy specification of +/- 0.1 0 C, a field Atmospheric standard would have to be developed to an accuracy of Stability
+/-0.025 0 C (i.e. 4 times better in accuracy, per standard Classes practice).
Implications on atmospheric stability classification are apparent.
Stability classes A and D-G could be estimated from a +/- 0.5 0 C system accuracy for temperature.
However, stability classes B and C might not be measurable.
Overall accuracy of the stability classification would be within 1 to 3 stability classes, for a (60m-1 Om) delta-T.2 Page 7 Atmospheric If extreme conservatism is necessary to provide an upper Footnote 6 Stability Class bound on X/Q concentrations, then an assumption of G Section 2 Methodology stability class and wind speed near the starting threshold (e.g. 0.5 mph) should just be made for all hours of meteorological data input. In cases where realistic results are more important, a site's meteorological data could be used, aided by a more accurate method for characterizing turbulence in the environment.
Item (1) above lends support to the need to advance the nuclear air dispersion models in the area of atmospheric stability classification.
NRC should consider models which utilize more accurate methods of stability categorization than the delta-T method for estimating atmospheric stability class,. One option would be EPA's SRDT method. A second option would be to incorporate current boundary layer (BL) meteorological parameters to characterize atmospheric turbulence.
NRC should then also provide standard methods of calculating the BL parameters from commonly/easily measurable variables.
Page 1 of 7 U. S. Nuclear Regulatory Commission December 4, 2006 Attachment Item DG-1 164 Topic Comment page and section 3 Page 10 Daily Channel Please specify what is meant by "channel operability checks" Section 5 Operability in the statement "Channel operability checks should be Checks performed daily and channel calibrations should be performed semiannually, unless the operating history of the equipment indicates that either more or less frequent calibration is necessary." Remote zero and span of data processors can be done daily via a datalogger.
This would be more practical than daily site visits to inspect the tower(s).
However, the zero and span would not ensure that the tower instrumentation is operating properly; it only checks the viability of the processors in the equipment building.4 Page 6 Dew Point For Dew Point, add to the explanation that "(T > Twet >Definitions Temperature Tdew)". This will aid the understanding on non-Section 1 meteorologists who use the Reg. Guide.5 Page 6 Pasquill For Pasquill Stability Class, the NRC should state preferred Definitions Stability Class methods, if any. Alternatively, NRC could amend the use of Section 1 stability class in lieu of other methods for turbulence characterization in the planetary boundary layer. In any case, it would be useful to include words to the effect that other methods for determining stability class or turbulence can be justified by the applicant, when appropriate.
6 Page 6 System For System Accuracy, please clarify to what extent network-Definitions Accuracy displayed meteorological data from a nuclear facility should Section 1 be considered in the calculation of "display" accuracy. (e.g., specify accuracy at the collection point/tower only, in Control Room, at the location where "QA'd" data is archived, or at the General Office or other location via the utility's computer network)7 Page 6 Temperature For Temperature, add to the explanation that (T > Twet >Definitions Tdew). This will aid the understanding of non-Section 1 meteorologists who use the Reg. Guide.Page 2 of 7 U. S. Nuclear Regulatory Commission December 4, 2006 Attachment Item DG-1 164 Topic Comment page and section 8 Page 6 Vertical Vertical Temperature Difference
-please amend wording Definitions Temperature from "...on the same tower" to "...typically on the same Section 1 Difference tower." Depending on tower size and arrangement, the lower level temperatures sensor (e.g. 1 Om) may in reality be on a separate, shorter tower, but still in the vicinity of (beside) a taller tower with a wide base, which would prohibit installation of a very long boom for the temperature sensor.In this case, delta-T should be considered as being from the same monitoring location, even though not quite on the same tower.Depending on the site's terrain, it is also possible that an overall stability class for an entire nuclear plant site could be determined from delta-T measurements using separate towers, that are not co-located, but which are instead on different parts of the plant property.
This could, in fact, be more representative of the vicinity than would just a standard delta-T measurement at the primary tower. For example, the delta-T at the taller, primary tower could be calculated, and also a delta-T for an adjacent valley below the plant grade using a shorter 1Oin tower, combined with upper level temperature data from the separate taller tower; thus deriving an indication of stability class in and over the valley.9 Page 7 Wet-Bulb For Wet-Bulb Temperature, add to the explanation that (T >Definitions Temperature Twet > Tdew).Section 1 In last sentence of the definition of wet-bulb temperature, delete the word "relatively":
"...the relatively drier air." Please provide a preferred or standard equation (that can be automated) for calculating wet-bulb temperature from measurements of temperature, dew point temperature, and pressure.10 Page 7 Meteorological For readability and ease of use, it would be useful to Section 2 Parameters separate the discussion of each meteorological parameter into subsections, or at least separate paragraphs, and move information out of footnotes into the main text, to the extent practical.
Page 3 of 7 U. S. Nuclear Regulatory Commission December 4, 2006 Attachment Item DG-1 164 Topic Comment page and section 11 Page 7 Vertical For Vertical Temperature Difference (Delta-T), please clarify Section 2 Temperature what constitutes a release point height "...significantly Difference greater than 60m." and Stability for the region and not just the site should be Atmospheric represented.
Are offsite temperature soundings from NWS Stability Class or other sources acceptable for greater heights above 60m?It would be helpful if the main text indicated that other methods of determining stability class can be justified by the applicant, but use of an alternative method in modeling may require modifications to the models (i.e., as opposed to this information being implied or footnoted).
It would also be useful if the NRC would described the acceptability of any X/Q models or non-radiological models (e.g. toxic gas) that currently allow for stability class based on the SRDT method or boundary layer parameterizations of turbulence, whether any are being developed, or any other possible options as alternative models.Conservatism in modeling should be limited to design basis items. Less conservative and more realistic modeling of impacts is also needed, with inherent error bounds identified.
Recommendations and decisions, based on more realistic modeling, could then be made as conservatively as desired, in the situation at that time.12 Page 8 Dew point vs. It would be helpful to indicate how much can the Section 2 Cooling measurement height for dew point temperature can vary Towers from the cooling tower release height, and still be representative of ambient conditions at that height.13 Page 9 Instrument Please clarify, in stating that the instruments should be able Section 4 Range to operate over the range of climatic conditions for the region, whether this means the range of climatological"extremes" per variable, or the range of climatologically"normal" values.Consider that wind speed measurements lose some accuracy in measuring lower wind speeds, if the instrument is set on the higher scale (0-90 mph). Measurements are more accurate at lower wind speeds if the instrument is set on the lower scale (0-60 mph).Page 4 of 7 U. S. Nuclear Regulatory Commission December 4, 2006 Attachment Item DG-1164 Topic Comment page and section 14 Page 11 Digital Data In discussing the sampling interval and compilation of data, Section 6 Sampling please clarify "mean" values as either an arithmetic mean Interval (i.e. averages), or as a geometric mean.15 Page 11 Wind Speed It would be helpful if the NRC were to include information on Section 6 and Wind the preferred measurement of wind speed and wind Direction direction, as either scalar or vector averages.16 Page 11 Fogging and It would be useful for the NRC to discuss/provide acceptable Section 6 Icing methods for determining joint frequencies for fogging and icing caused by plant operation only, and not due to ambient fogging and icing.Note: The frequency of (T=Tdew) or (T<32F) would only indicate ambient, natural conditions, not necessarily due to the plant operation.
17 Page 11 Protective Please clarify what is meant by the term "keyhole" protective Footnote Actions action.11 18 Page 12 EAL's It is not clear why the meteorological instruments must be Section 8 vs. able to survive the extreme conditions upon which a facility's emergency action levels are based. It would seem the EAL MET Sensors could be entered into sooner, based on loss or over-ranging of the sensor. Further, an EAL could be based on forecast conditions, and thus, the actual measurements may not matter anyway.Note: On the Saffir-Simpson scale, Category 1 hurricane wind speeds are 74-95 mph.Example: If a high wind EAL exists at 75 mph, then a station could implement the EAL when the anemometer peaks out at 60 mph (when on a 0-60 mph scale). This is a more conservative approach and provides the best accuracy for the routinely lower wind speed measurements.
Page 5 of 7 U. S. Nuclear Regulatory Commission December 4, 2006 Attachment Item DG-1 164 Topic Comment page and section 19 Page 12 Display of Display of MET data in the control room and Emergency Section 8 MET Data Operations Center, or on computers therein, provides the current conditions, but formatting of data for model input is usually handled by pre-processors, internal to or associated with the emergency response models. The guidance should state that, while the parameters used should be displayed, they do not need to be in the same format as the model's input stream.If atmospheric stability is not calculated on plant computers, only Delta-T measurements would be displayed as an indicator of stability class in the control room or in ERDS.Stability is calculated either by the emergency dose model, or manually, as part of the station procedure for the Dose Assessment groups.20 Page 12 ERDS At the June 2006 NEI EP and Communications Forum, Eric Section 8 Leeds (NRC) stated that ERDS was going to be replaced with a better system. While ERDS is routinely tested and does work, it was created in the late 1980s and is a non-networked system. Many improvements could be made to facilitate the transfer/sharing of plant information and meteorological data during an emergency.
Will a replacement for ERDS be available in time to be referenced in DG-1164?Note that all of the available meteorological data points for a particular facility might not be set up in ERDS. In addition, station emergency response procedures may require the use of upper level wind direction with lower level wind speeds in dose assessment models for conservatism.
Thus, there is a chance for miscommunications between NRC and a facility's Emergency Response Organization (ERO) staff, depending on which information is available and which is used for dose assessment and plume tracking by NRC versus ERO staff.Page 6 of 7 U. S. Nuclear Regulatory Commission December 4, 2006 Attachment Item DG-1 164 Topic Comment page and section 21 Page 12 Alternative When onsite delta-T data is not available, are other methods Section 8 MET Data for determining stability class acceptable to NRC during an Sources emergency?
Some possibilities may be use of convective potential or helicity related indices from NWS soundings or weather forecast models.Should the alternative MET data be input/substituted into ERDS? Current station emergency procedures include calling the local NWS office to obtain back-up data verbally, if the onsite MET data is unavailable.
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