ML18018B430
| ML18018B430 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 09/30/1983 |
| From: | EBASCO SERVICES, INC. |
| To: | |
| Shared Package | |
| ML18018B428 | List: |
| References | |
| NUDOCS 8311020126 | |
| Download: ML18018B430 (15) | |
Text
ANALYSIS OF HABITABILITY OF THE SHEARON HARRIS NUCLEAR POWER PLANT TECHNICALSUPPORT CENTER Prepared for CAROLINAPONFR 8 LIGHT COMPANY EEAKO EBASCO SERVICES INCORPORATED SEPTEMBER 1983.
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TABLE OF CONTENTS
~Pa e No.
1.
INTRODUCTION 2.
DIRECT RADIATION EXPOSURE ANALYSIS 3.
EXPOSURE TO RADIONUCLIDES AIRBORNE INSIDE THE TSC 2
3.1 Methodology 3.2 Assumptions and Parameters 3.3 Results and Conclusion 2
REFERENCES
LIST OF TABLES AND FIGURE TABLE 1 - Direct Shine Doses to TSC Personnel From Radioactivity on Emergency Ventilation System Filters TABLE 2 - Inhalation and Submersion Doses to TSC Personnel Following a Design-Basis Loss-of-Coolant Accident FIGURE 1 - Technical Support Center Emergency Ventilation System Air Flow Diagram
1.
INTRODUCTION This study is performed to determine the habitability of the Technical Support Center (TSC), after a radiological accident at the Shearon Harris Nuclear Power Plant (SHNPP).
General Design Criterion 19 (GDC-19) (Ref. 1)
Appendix A to 10CFR50 specifies a radiation exposure limit of 5 rem whole body, or its equivalent to any part of the body of personnel within the facility for the duration of the accident.
The analyses presented in this report are provided in two sections.
The first section, entitled Direct Radiation Exposure Analysis, addresses direct radiation exposure from 1) local sources of radiation,
- 2) radionuclides in containment,
- 3) airborne radionuclides which may leak from containment and are transported to areas adjacent to the TSC and 4) buildup of radionuclides on emergency filtration systems located within the facility.
The second section of the report, entitled Exposure to Radionuclides Airborne Inside the TSC, addresses the whole body, thyroid and skin doses to occupants due to intake of airborne radionuclides into the facility.
A major loss-of-coolant accident (LOCA) is the design basis event which provides the emergency condition for habitability.
2.
DIRECT RADIATION EXPOSURE ANALYSIS The shielding analysis for the TSC has been performed in accordance with the assumptions stated in Section 12.3.2.16 of the SHNPP FSAR.
The source term used in the calculations is described in Section 12.2.1.12.
The TSC is located in the Fuel Handling Building at Elevation 324'nd 'is separated from the containment by an additional six feet of concrete and a
minimum distance of 88 feet.
Dose rates near the containment due to direct shine are shown on page 12.3A-10 of the FSAR for Region R 27 (area immediately outside containment).
All radioactive piping of interest is located below Elevation 261'n the Reactor Auxiliary Building and is separated from the TSC by six feet of concrete and a distance of 110 feet.
These sources do not make a significant contribution to dose rates in the TSC.
The emergency ventilation system filters, located in the mechanical room of the facility, have been postulated to be the most relatively significant source of direct exposure.
Dose rates due to this source at various time intervals in different areas of the facility are shown in Table 1.
These dose rates are within the limits for continuous occupancy of the facility.
3.
EXPOSURE TO RADIONUCLIDES AIRBORNE INSIDE THE TSC The TSC is designed with one outside air intake at Elevation 336'NSL) in the southwest corner. of the Fuel Handling Building along the west wall.
The room containing the ventilation equipment (charcoal filters, etc.) is in the southwest quadrant separated from the rest of the facility by a 12" block wall.
In an emergency condition or when radiation is detected in the air stream, outside air will be drawn for ventilation and pressurization through the emergency ventilation filtration system (HEPA filter and charcoal adsorber) before it is distributed to the ceiling cavity.
A radiation detector at the outside air intake is used for automatic operation of the filtration system.
There are low leakage dampers to be used for isolation of air streams, arranged such that untreated air will not infiltrate through the closed dampers.
3.i
~ft th d1 The habitability of the TSC is assessed against its capability to maintain doses to its occupants below the limits of GDC-19 and SRP 6.4 (Ref.
- 2) followirg a design-basis LOCA.
Gaseous radionuclides leaking from the containment are the source of the radioactivity reaching the TSC outside air intake (OAI).
The radioactivity concentration at the OAI is calculated based on the guidance given in Reference 3.
Airborne radionuclides enter the facility as a result of the pressurization makeup air and uncontrolled air in-leakage from opening and closing of the TSC doors.
(It should be noted, however, that the latter source of contaminated air into the TSC has been included for conservatism since the TSC design calls for the use of air-locks.)
The TSC radionuclide concentration is calculated based on the design values of the filtered air makeup and recirculation flow rates.
The dose calculation models are given in Appendix 15.0.A of the FSAR.
A conceptual presentation of the emergency ventilatfon system and air flows is given in Figure 1.
3.2 Assum tions and Parameters The following assumptions and parameters are used in the habitability analysis:
1) design basis assumptions presented in FSAR Section 15.6.5.4.
1 are applied, 2) an accident duration of 30 days,
3) a net free TSC volume of 88,096 ft (2,495 M ) which allows 10K of the TSC volume for furniture and equipment, 4) radionuclides are uniformly distributed throughout the TSC volume, 5) the TSC outside air intake is located at Elevation 336';
106 ft.
below the containment
- dome,
- 6) filter efficiency of TSC emergency ventilation filters for iodine is 99K, representing 4" or greater of charcoal
- beds, 7) finite cloud correction is applied, 8) a breathing rate of the TSC occupants of 3.47 X 10 cubic meters per second for the duration of the accident, 9) occupancy of the TSC is based on the following:
Time Period 0 to 24 hrs.
1 to 4 days to 30 days Occu anc Factor 1.0 0.6 0.4 10) post accident atmospheric dispersion factors are calculated using recommendations in Reference 3.
These X/Qs are then adjusted by applying an overall reduction factor to account for the effects of changes in wind speed, wind direction and occupancy factor.
The adjusted X/Qs are:
Time Period Ad 'usted X/
sec/m 0 to 8 hrs.
8 to 24 hrs.
1 to 4 days 4 to 30 days 3.68 X 10 2.17 X 10 8.46 X 10 2.43 X 10 ll) pressurization makeup air flow rates of 800 cfm (minimum) and 1200 cfm (maximum),
12) the fan capacity for air recirculation is 2,400 cfm, and 13) an unfiltered inleakage into the pressurized TSC of 3 cfm.
3.3 Results and Conclusion The inhalation and submersion doses to the whole body, skin and thyroid of a TSC occupant are presented in Table 2.
The direct shine doses are not included because of their negligible contribution.
The results indicate that the doses are within the GDC-19 and SRP 6.4 guidelines of 5 rem for whole body and 30 rem for skin and thyroid.
The Technical Support Center is therefore designed to be habitable in the event of a design-basis LOCA.
References:
l.
Standard Review Plan (NUREG-0800), Section 6.4 3.
Nuclear Power Plant Control Room Ventilation System Design for Meeting General Criterion 19, K G Murphy and K M Campe, 13th AEC Air Cleaning Conference, 1973
TABLE 1
Direct Shine Doses to TSC Personnel From Radioactivity on Emergency Ventilation System Filters (MREM(HR)
AREA 1
HR 1
DAY 1
MONTH Decon Facility NRC Team Outside Agencies Accident Assessment Command Team 5.1 0.5 0.4 0.1 1.1 13.2 1.2 1.0 0.4 2.8 0.07 0.006 0.005 0.002 0.014
TABLE 2 Inhalation and Submersion Doses to TSC Personnel Following a Design-Basis Loss-of-Coolant Accident (REM)
Pressurization Makeup Air Flow Rate (CFM) 30-Da Doses Whole Body Skin Thyroid 800 1200 0.8 0.9 19 20 19 26
c Ih, l
~
FIGURE 1 TECHNICAL SUPPORT CENTER EMERGENCY VENTILATIONSYSTEM AIR FLOVf DIAGRAM F1. 800 cfm (MIN) 1200 cfm (MAX)
OAI "I.
I
)
I PI H
I C
i C
I I
I I
2400 c/fm AIR-LOCK
~F3< 3cfm F2'. F1+ F3 NOTES:
OAI: OUTSIDE AIR INTAKE P: PRE-FILTER H: HEPA FILTER C: CHARCOALADSORBER