ML20071B371

Forwards Sys Description for Proposed Upgrade to Meteorological Sys Including Class a Model.Upgrade Will Be Completed by Fuel Load

ML20071B371
Person / Time
Site:	Catawba
Issue date:	02/21/1983
From:	Tucker H DUKE POWER CO.
To:	Adensam E, Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 8302280199
Download: ML20071B371 (8)

Text

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DUKE POWER GOMPAhT v.o.nox amao CHAMLoTTE, N.C. 28242 HALB. TUCKER TEI.EPHONE WMM,mEstDENT (704) 3MS38 -

February 21, 1983 mm,--

Mr.. Harold R. Denton, Director

-Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.

20555

-Attention: Ms. E. G. Adensam, Chief Licensing Branch No. 4 i

Re: Catawba Nuclear Station Docket Nos. 50-413, 50-414

Dear Sir:

Attached please find a system description for the proposed upgrade to the meteorological system at Catawba including the Class A model. This upgrade will be completed by fuel load..

Very truly yours, f e

.al B. Tucker JSW:scs Attachment cc:

Mr.. James P. O'Reilly, Regional Administrator Mr. P. K. Van Doorn U. S. Nuclear Regulatory Commission NRC Resident Inspector Region II Catawba Nuclear Station 101 Marietta Street. Suite 3100 Atlanta, Georgia 30303 Robert Guild, Esq.

Palmetto Alliance Attorney-at-Law 213515 Devine Street P. O. Box 12097 Columbia, South Carolina 29205 Charleston, South Carolina 29412 Mr. Jesse L. Riley Mr. Henry A. Presler, Chairman Carolina Environmental Study Group Charlotte-Mecklenburg Env.

854 Henley Place Coalition Charlotte, North Carolina 28207 943 Henley Place Charlotte, North Carolina 28207

]W B302280199 830221 PDR ADOCK 05000413 F

PDR

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~ CATAWBA METEOROLOGICAL SYSTEM i-t 4

INTRODUCTION-t In response to guidance provided by NUREG-0654 Revision 1 and supporting docu-

• ments, Regulatory Guide 1.23.' Proposed Revision 1, Regulatory Cuide 1.111 Revision 1 and Regulatory. Guide 1.109, Duke has reviewed.the existing meteoro-logical system at Catawba Nuclear Station and,' based onLthat review, has developed

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a' plan for upgrading'the meteorology-system. This functional description of the

. upgraded meteorological system is intended to provide compliance with NUREG-0654, Appendix 2.'.

The present meteorological measurement program at Catawba Nuclear Station was originally designed to best describe ~the meteorological. conditions on-site by-

'taking into account source characteristics, terrain features and modeling needs.

Ihun to revisions to guidelines, Duke has developed changes to upgrade assessment capabilities'and reliability of the ueteorological programs at Catawba Nuclear Station.-

Basically, these changes will:

1) Establish a capability to assess near real time 15 minutes averaged / validated l

Edata with a 12-hour recall and associated dose estimates within 15 minutes of request.that account for variability in' travel path of effluent material.

2) Improve reliability and accuracies through upgraded instrumentation and upgrading of mereorological data, other dose related measurements, and dose

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estimatesaas needed.

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EFFLUENT DISPERSION MODEL

'The Class A Model which will belused in the transport and diffusion of released

. effluents;is a puff-advection model which incorporates a' horizontal wind field.

that can vary in.tima, and space. It is assumed in the puff-type model that the spread within a puff along the direction of flow is equal to the spread in the lateral direction (i.e., horizontal Guassian Symmetry). In the model, concen-

-tration averages are provided by total integrated concentrations which are calculated by summing concentrations of individual elements for the grid points over which the puffs pass. Features to be incorporated'into the model include the use of predicted and edited primary or backup data, where appropriate, terrain effects, building wake effects,. ground or elevated release mode, and

'special features used to describe site-specific meteorology. Appropriate per-sistence and worst case meteorology will be used for initial releases until a meteorologist is notified to provide predictive data.

i INSTRUMENTATION

. Table i shows the type and number of parameters to be measured at Catawba Nuclear Station after upgrading of the system. The meteorological conditions present at t

Catawba Nuclear Station warrant the use of the basic described meteorological These include wind speed and wind direction measured at high and low variables.

levels,. delta temperature for stability classification, ambient air, and dew point temperature, and precipitation.

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DATA HANDLING The dose calculation system consists of a primary digital recording / storage system and a secondary analog chart recording system. The meteorological vari-ables will be sampled at 60 second intervals for the digital system except for variables used to calculate sigma theta, these will be sampled every 5 seconds.

Prior to meteorological data use or storage, the data will go through a series of edit checks which include range comparisons and data inter-comparisons to determine validity of data and whether backup data should be used.

Upon validation, the data will be placed on 12-hour recall for emergency efflu-ent dispersion modeling and dose calculation. Validated data will also be stored on a magnetic medium as one-hour average for future use and to meet the 90% joint annual data recovery requirements.

DOSE ASSESSMENT METHODOLOGY The dose assessment methodology for Catawba consists of two separate calcula-tions. The first calculation is based on the amount of radioactivity that has been or is actually being released through the unit vent; the second calculation is based on a potential release using actual source term and design basis assumptions for containment leakage.

To determine the dose from an actual release through the unit vent. both the concentration of isotopes in the unit vent and the unit vent flow rate must be known. Unit vent grab sample analyses are used to determine the isotopic con-centrations of the release. When this information is not available, unit vent radiation monitors and their energy dependent sensitivities are used. The flow rate is obtained from the unit vent flow rate monitor. The combination of flow rate and isotopic concentrations is used to determine the actual release rate through the unit vent.

If substantial radioactivity is present in the containment, another calculation is performed. The calculation provides the dose potential for a release based on the radioactivity present in the containment. A containment atmosphere sam-ple is used to determine the isotopic concentrations.

If this information is unavailable, the containment building area radiation monitor is used to deter-mine the severity of the accident by comparison with design basis source terms.

The containment design leak rate is used unless factors, such as containment pressure, indicate that another value is more realistic. The isotopic concen-trations combined with a containment leak rate provide a potential release rate of activity.

The dose model calculates both cumulative and projected doses. Downwind concen-trations are determined by applying the relative atmospheric dispersion factors calculated by the meteorological model. Projected concentrations are determined in one-hour increments up to a period of four hours. A forty-year thyroid dose commitment and a whole body dose from exposure to a semi-infinite cloud are deter-mined. The dose conversion factors are derived from Regulatory Guide 1.109.

This dose assessment methodology provides the capability to calculate the dose from actual or potential releases following an accident. Near real time radia-tion monitor readings and meteorological data are combined automatically to i

provide timely, realistic dose calculations. However, the flexibility to manually.--...

input sample data is also provided. LThis model meets the guidance to NUREG-0654, Revision 1, Appendix 2 to provide the capability "to assess and monitor actual or potential off-site consequences of a radiological emergency condition."

UPGRADED PHYSICAL SYSTEM DESCRIPTION The conceptual. layout for the meteorological system is presented in Figure 1.

The sensors for the meteorological system are mounted on existing towers. The signals will enter each Unit Operator Aid Computer (OAC) and the analog system.

Thi meteorological data will be stored on the OAC and can be transferred routinely or during an emergency situation to the Distributed Data Processor (DDP) via a manual transfer of a diskette from a OAC disk drive to a remote disk drive..The Class A Model calculations will be made on the DDP system. Routine meteorological data will be stored through the Distributed Data Processor System.

In the event of an emergency, it will have the capability to recall 12-hour meteorological data, radiation monitor data, perform Class.A Model calculations, and provide the inputs and calculated outputs to all appropriate site emergency response areas.

DETAILED DESCRIPTION OF SUBSYSTEMS j

Sensors to Operator Aid Computer The parameters to be seasured by the meteorological system are listed in Table 1.

These meteorological sensors will meet the accuracies suggested r

in Regulatory Guide 1.23, Proposed Revision 1.

Signals from the meteoro-logical system to the OAC (digital system) and analog charts will be cabled to the plant. Housing for signal conditioners and related instrumentation will be housed near the high level tower. Uninterruptible power supplies will be provided to assure continuous operation of the meteorological system. Sensors, conditioning equipment and instrumentation will have lightning protection and will be heated where necessary to minimize effects of adverse environmental conditions. Signal cables will-be shielded to minimize electrical interference.

Operator Aid Computer (OAC) to Distributed Data Processor (DDP)

The process computer OAC system which is utilized for data collection con-sists of GE/Honeywell 4000 series equipment. Inputs from the sensors (Figure 1) will be wired to the OAC and will be scanned according to guid-l ance provided by Regulatory Guide 1.23, Proposed Revision 1.

Predefined meteorological inputs will be averaged for 15 minutes and the average will j

be stored for later use. The OAC has bulk storage capability for 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />

. worth of 15 minute averages.

Data retrieval from the OAC will be initiated at the Performance Typer in the computer room. Each unit OAC is a backup for the other, capable of supplying the same required meteorological readings. The data will either be printed in a tabular format or stored on a floppy disk (diskette) which is designed for data exchange applications. Upon output completion, the data will be removed from the OAC and additional data can be taken.

By means of a separate floppy disk reader attached to a data communications terminal in proximity to the OAC, the data will be transmitted to an off-line computer facility either on-site, or remote to the station. Each set of data readings will be stored in an on-line data base for recall on demand.. _.

The data will be subjected to validation procedures through both soft-ware and manual methods.- Immediately upon completion of the validation procedures, the data will be available to designated agencies through dial-in terminal facilities. The data will further be available for both periodic archiving and for immediate processing by the puff-advection model. Output from this model may also be made available to designated agencies in a read only mode.

The primary off-line data processing facility will be the station

. distributed data processor (DDP). First line backup to the station facility (See Figure 2) will be a similar DDP facility in the General Office in Charlotte, North Carolina. Additional backup facilities are available at each of the other nuclear stations. The capability will also be-provided to process this data in the Charlotte Corporate Computer Center.

QUALITY ASSURANCE In response to point 7, Quality Assurance of Regulatory Guide 1.23, Proposed Revision 1, new equipment will be purchased from suppliers who have provided high quality, reliable equipment in the past. Documentation concerning fabrica-tion and assembly of the components will be considered on a case-by-case basis as is normal for non-10CFR 50, Appendix B items.

Tower modifications, cabling and computer hardware will be. designed, procured and installed as a non-safety-related system.

Surveillance during construction will be provided the same as for any other non-safety system.

Maintenance, calibration and repair procedures, and logs will be available at the site for inspection. The procedures and logs will be designated as site controlled documents. Inventories of meteorological system spare parts, sensors and components will be incorporated into existing company procedures.

4 TABLE 1 Catawba Nuclear Station Meteorological Parameters of the Upgraded System Primary System Existing high level and High level wind speed and direction 10 meter towers Low level wind speed and direction Delta temperature (stability)

Dry bulb temperature Precipitation Dew point 1

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.,,.<.-,-.-w--.---.----wa.-,,.-a

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4 Figure 1.

Catawba Nuclear Station' Generalized Meteorological System Upgrade C

Sensor /

Instrumentation Rad Rad Input Input Unit 1 Unit II i

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OAC OAC 1r Analog Chart System Data Transfer Via Diskette Writer / Reader

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DDP Computer System TSC, EOF, CR Remote Interroga4 Other Display tion Capability Areas ir Permanent Storage n

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NUCLEAR STATION OFFLINE COMPUTER SUPPORT f

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Corporate

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' Commercial \\

Computer l Agencies, I

Computing i

I Centers I

Center g Vendors

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9600 BPS Charlotte General Office DDP 9600 BPS 9600 BPS 9600 BPS O

l OAC Oconee Catawba OAC Data l

DDP l

i McGuire l

OAC o

Data o

Notes

1) 5 denotes dedicated communications

2) p denotes 4800 BPS dial-up coammunications capability

3) Dedicated 9600 BPS commmunications to Corporate Computer Center from each station DDP schedule for 1982.

4) 9600 BPS network of DDP's scheduled for cross-connection (i.e., as opposed to current " star" network) in 1983.

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