ML20042G541
| ML20042G541 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 05/09/1990 |
| From: | Watson R CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NLS-90-102, NUDOCS 9005150056 | |
| Download: ML20042G541 (7) | |
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P. O ses 1841
- Reiseph, K C. 27002 i
WAY 9 1990 l
j d' E SERIAL: NLS 90-102 mener eeneesa United States Nuclear Regulatory Commission l
ATTENTION:
Document Control Desk i
Washingtor., DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50 325 6 50 324/ LICENSE NOS. DPR.71 & DPR 62 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION t
AllhWABLE CONTAINMENT LEAK RATE Centlemen:
l On March 5, 1990, Carolina Power & Light Company received a request for
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information, via telecopy, regarding the October 10, 1989 license amendment i
request to raise the allowable containment leak rate (L.) at Brunswick from 0.5 volume percent per day to 1.0 volume percent per day. This information was requested to aid the NRC staff in performing independent offsite and control room operator dose calculations. contains the requested information.
l Please refer any questions regarding this submittal to Mr. M. R. Oates at (919) 546 6063.
Yours very truly, fh[h&O h
R. A. Watson I
RAW / MAT Enclosure cc:
Mr. Dayne 11. Brown Mr. S. D. Ebneter Mr. N. B. Le Mr. W.11. Ruland R. A. Watson, having been first duly sworn, did depose and say that the infor-J mation contained herein is true and correct to the best of his information, knowledge and belief; and the sources of his information are officers, employees, contractors, and agents of Carolina Power & Light Company.
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ENCIDSURE 1 BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 NRC DOCKETS 50 325 & $0 324 OPERATING LICENSES DPR 71 & DPR 62 l
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION l
ALlhWABLE CONTAINMENT LEAK RATE l
staff Reauent 1 Core Thermal Power Level (MWt) (includes an additional 24 for instrument error).
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Response
The core thermal power level to be used in this calculation is'2550 MWt.
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Staff Reauest 2 Control Room Unfiltered In+1eakage (cfm).
Resnonse The control room unfiltered in leakage is 3000 cfm. This information was not used in the calculation of control room doses.
Instead, a bounding analysis.
which demonstrated on a worst case basis that control room doses were directly proportional to the primary containment leak rate, was used.
For example, if the leak rate doubled, then the control room dose rate doubled.
r Staff Reauest 3 Control Room Volume (ft ).
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r Resconse
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3 The control room volume is 298,650 ft.
This information was not used in the calculation of control room doses.
See. response to Staff Request 2 _
r Staff Reauest 4 I
Control Room Normal Ventilation System Charcoal Adsorber Iodine Removal l
Efficiency (%),
s
Response
The control room normal ventilation system charcoal adsorber iodine removal efficiencies are as follows' Elemental Iodine 95%
Methyl Iodine 90%
Particulate Iodine 95%
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This information was not used in the' calculation of control room doses. See response to. Staff Request 2.
Staff Reauest 5 3
Breathing Rate (m /sec).
Response
The following breathing rates were used in performing the dose calculations.
Offsite Control Room 3
3 0 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 3.47 x 10*' m /sec 3.47 x 10 m /sec 8 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 1.75 x 10 m /sec
'3.47 x 10 m /sec-3 3
1 to 30 days 2.32 x 10 ud/sec 3.47 x 10 nd/sec Control room breathing rates were not used in the calculation of control room.
doses.
See response to Staff Request 2.
Staff Reauest 6 Control Room Recirculation Rate (cfm).
Resoonse The control room recirculation rate is 1000 cfm. This information was not used in the calculation of control room doses.
See response to Staff Request 2.
Staff Reauest 7
[
Control Room Emergency Ventilation Rate (cfm).
Response
The control room emergency ventilation rate is 1000 cim. This information was not used in the calculation of control room doses..See response to Staff.
Request 2.
Staff Reavest 8 Occupancy Factors.
Response
The following occupancy factors are assumed for calculation of offsite and control room doses.
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-__-__ - -_ - - - - - - ~_ -.
Offsite Control Room 0 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 1.0 1.0 8 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 1.0 1.0 1 to 4 days 1.0 0.6 4 to 30 days 0.333 0.4 Control room occupancy factors were not used in the calculation of control room doses.
See response to Staff Request 2.
Staff Recuest 9 Primary and secondary containment f::ce volume.
Resnonse The primary and secondary containmant free volumes were not used in the calculation of the offsite doses.
Instead the primary containment leakage w,as expressed as a fraction per day leaked into the reactor building.
The analysis then assumed that all of the primary containment passed directly into the emergency exhaust without mixing with the surrounding atmosphere.
This approach represents maximum conservatism.
The primary and secondary containment volumes were used in the analysis of the environmental qualification doses. These volumes are:
Primary Containment Volumo 298,700 ft3 (sum of drywell and wetwell)
Reactor Building Free Volume 2.6 x 106 ft3 Staff Reauest 10 Annulus Exhaust (Standby) Gas Treatment System Flow Rate (cfm).
Response
The annulus exhaust (Standby's gas treatment system flow rate was not used in determining the offsite doses. All activity released from the primary containment is assumed to be directly released through the SGTS regardless of flow. The flow rate was usod in determining the environmental qualification doses.
This flow is as given in the Brunswick Updated FSAR Section 6.5.1.1.1 which states that each filter train blower in conjunction with the secondary containment ducting was denigned to maintain a negative secondary containment pressure of 0.25 inches of water by controlled venting at the rate of 100%
volume per day following reactor building isolation. Table 6.5.1 1 of the Brunswick Updated FSAR gives the design blower capacity of 3000 cfm against an external pressure of 3 inches of water.
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Staff Reouest 11 Secondary Containment Pressure Drawdown Time (min).
Response
A value was not obtained for the secondary containment drawdown time since the j
reactor building is normally operated at a negative 0.25 inches of water.
The Brunswick FSAR Section 15.6.4.1.2 assumes a leak rate for the reactor building of it/ day.
The analysis assumes that 1% of the primary containment leakage bypassed the SGTS filters for the entire duration of the event without credit for hold up and dilution in the reactor building.
NUREG 0800, Section 6.5.3, Paragraph III.c states that large reactor buildings around older BWR containments are usually maintained at a negative pressure-during normal operation, and the dose model assumed for these cases has not assumed any positive pressure period.
Brunswick System Description SD 31.1, Revision 7 dated May 17, 1988 states that the reactor building exhaust and supply fans are operated in such a manner as to maintain a negative static pressure of 0.25 inches of water.
Staff Recuest 12 Annulus Exhaust (Standby) Gas Treatment System Charcoal Adsorber Iodine Removal Efficiency (%).
Response
The following are the SGTS charcoal adsorber efficiencies.
Elemental Iodine 99%
Methyl Iodine 99g Particulate Iodine 994 Staff Reauest 13 Maximum Main Steam Isolation Valve Leak Rate (cfh).
I
Response
The calculations for control room doses and offsite doses do not include a contribution from MSIV leakage.
It is assumed that there is no direct leakage from the primary containment to the environment.
All exhaust from the secondary containment is directed through the standby gas treatment system.
This is consistent with the Brunswick Control Room liabitability Studies j
submitted March 2, 1983 and August 30, 1985 and accepted by the NRC on October
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18, 1983 and February 16, 1989, respectively, i
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The maximum MSIV leakage is established by lechnical Specifications independent of.the Integrated Leak Rate Test limit. MSIV leakage is maintained at or below 11. '> scfm per valve in accordance with Technical Specification Section 3.6.1.2.
Staff Kaauest 14 3
Atmospheric Dispersion Coefficients, X/Q values (sec/m )
a.
Containment leakage b.
Main Steam Isolation Valve Leakage c.
Elevated (Stack) Release
Response
No Atmospheric Dispersion Coefficients for containment leakage were used a.
since one of the assumptions-is that 100% of all leakage exits from primary containment directly into the intake of the.SGTS.
Dilution and dispersion in the reactor building is not taken into account.
See response to Staff Roquest 9.
b.
No Atmospheric Dispersion Coefficients for the Main Steam Isolation Valve Leakage are used..See response to NRC Request 13.
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c.
The following Atmospheric Dispersion Coefficients (in sec/m ) are used for Elevated Stack releases:
11gg EXCLUSION AREA LOW POPU1ATION ZONE Thyroid Whole Body Thyroid Whole Body 0 1/2 hr 1.14 x 10
1.14 x 10
3.63 x 10 5 3.63 x'10 5 1/2 2 hr
- 1. 33 x 105 2.46 x 10 5
- 7. 81 - x 10 6 l'.10 x 10 5 2 8 hr 7.81 x 10
1.10 x 10 5 8 24 hr 3.25 x 10
4.59 x 10 6 1-4 days 1.04' x 10 6 1-.22 x 10 6 4 30 days
- 3.47 x 10'7 4.07 x 10*7
- 1/3 occupancy has been included in values for this period; Ilme Control Room X/Os 0 1/2 hr
- 3. 3 x 10
1/2-8 hrs
- 1. 8 x 10 6 8 24 hrs 1.1 x 10 6 1-4 days 2.0 x 10'7 4 30 days 2.7 x 10'8 Control Room X/Qs include occupancy factor.
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Stack Data Height.100 m:
Distance to exclusion zone 3000 ft.
Distance to low population tone.2 miles Staff Reauest 15-Control Room' Isolation Time.(sec)
Response
l' The 1983 report,, Response to. NUREG 0737. TM1 Action' Item' 111.D.3.4, dated March 2, 1983, uses a closure rate of 7 seconds -This is conservative with respect to the' design of the damper. The control room isolation time was not used in the calculation of control room doses.
Request 2.
. See-response to Staff-L El-6 p
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