ML20148J323

Proposed TS Reflecting Latest Rev of Waste Gas Decay Tank Rupture Accident Dose Calculation

ML20148J323
Person / Time
Site:	Byron, Braidwood
Issue date:	06/09/1997
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML20148J310	List: ML20148J303 ML20148J323
References
NUDOCS 9706170106
Download: ML20148J323 (6)

Text

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ATTACilMENT B

PROPOSED CIIANGES TO TIIE BYRON /BRAIDWOOD UFSAR REVISED PAGES 15.0-47 15.0-49 i

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BYRON-UFSAR TABLE 15.0-11 (Cont'd) 4 DOSE (2 HOURS) AT EXCLUSION DOSE (COURSE OP ACCIDENTI AT

' AREA BOUNDARY LOW POPULATION EfMe 3

(445 meters) (4828 meters) l UFSAR POSTULATED ACCIDENT SRCIIQli THYROID (REM) WHOLE BODY fREM) THYROID fREM)

! WHOLE BODY fREM) i Process Gas System

. Rupture 15.7.1 l

Conservative 0 1.02 (+0) 0

} Reslistic 0 3.05 (-2) 6.5% (-3) 0 1.54 (-4)

Radioactive Liquid l'

Waste System Failure 15.7.3 Spent Resin Tank 2.83 (-1) 8.30 (-5)

Recycle Holdup Tank 9.90 (-3) 2.50 (-1) 8.40 (-3) 2.50 (-6) i 3.00 (-4) 7.60 (-3)

Fuel Handling Accident in Cbn-tainment 15.7.4 Conservative  !

Realistic In Fuel Building Conservative 2.44 (+1) 7.30 (-1) 1 Realistic 7.30 (-1) 2.18 (-2) 1.37 (-3) 1.62 (-4) 3.16 (-5) 3.75 (-6)

10CFR100 limits 300 25 300 l'

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• Realistic analysis based on 50th percentile meteorology.

Conservative analysis based on 5th percentile meteorology.

• Notes 2.89 (+1) = 2.89 x 108 4

6 j 15.0-47 REVISION 6 - DECEMBER 1996 1 -

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BRAIDWOOD-UFSAR TABLE 15.0-12 (Cont'd) 1 DOSE (2 HOURS) AT EXCLUSION DOSE (COURSE OF ACCIDE!TT) AT AREA BOUNDARY LOW POPULATION ZONE (485 meters) (1811 meters)

UFSAR POSTULATED ACCIDENT SECTION THYROID (REM) WHOLE BODY (REM) THYROID (REM) WHOLE BODY (REM)

Process Gas System Rupture 15.7.1 Conser"ative 0 1.38 (+0) 0 1.27 (-1)

Realistic 0 7.11 (-3) 0 6.61 (-4) 4 3 Radioactive Liquid Waste System Failure 15.7.3 Spent Resin Tank 3.83 (-1) 1.40 (-4) 3.50 (-2) 1.00 (-5)

Recycle Holdup Tank 1.30 (-4) 3.40 (-1) 1.20 (-3) 3.10 (-2)

Fuel Handling Accident in Con-tainment 15.7.4 Conservative Realistic In Fuel Building Conservative 3.30 (+1) 9.86 (-1) 3.05 (+0) 9.09 (-2) l Realistic 1.50 (-3) 1.si (-4) 1,39 (-4) 1.65 (-5) 10CFR100 lit ~'rc 300 25 300 25

• Realistic analysis based on 50th percentile meteorology.

. Conservative analysis based on 5th percentile meteorology.

. Note: 3.90 (+1) = 3. 90 x 10' 15.0-49 REVISION 5 - DECEIGER 1994

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ATTACllMENT C EVALUATION OF SIGNIFICANT IIAZARDS CONSIDERATIONS FOR PROPOSED CIIANGES TO Tile BYRON /HRAIDWOOD UFSAR l Comed has evaluated this proposed change and determined that it involves no significant l hazards considerations. According to 10 CFR 50.92(c), a proposed amendment to an operating license involves no significant hazards consideration if operation of the facility in accordance with the proposed change would not: '

l 1. Involve a significant increase in the probability of occurrence or consequences of an i accident previcusly evaluated;

2. Create the possibility of a new or different kind of accident from any previously analyzed; or

3. Involve a significant reduction in a margin of safety.

l Comed proposes to increase realistic whole body doses for the process gas system rupture accident above that previously reviewed and approved by the NRC as part of the licensing l

basis for the plant. The change is based on a revision to the dose calculation for that accident.

The determination that the criteria set forth in 10 CFR 50.92 are met for this request is indicated below:

1. Does the change involve a signiGcant increase in the probability or consequences of an accident previously evaluated?

The proposed changes involve a slight increase to the consequences of the wnste gas decay tank rupture event as shownin UFSAR Tables 15.0-11 and 15.0-12. However, the values continue to be less than a small fraction of the 10 CFR 100 limits, i.e.,10 percent or 2.5 rem for whole-body dose. Standard Review Plan 11.3, Branch Technical Position (BTP) ETSB 11-5," Postulated Radioactive Releases Due to a Waste Gas System Leak or Failure," in NUREG-0800, July 1981 imposes lower dose limits than 10 CFR 100 because the probability of an accidental release from the waste gas system is relatively high. The BTP establishes a limit of 0.5 rem to an individual at the nearest exclusion area boundary.

The rxalculated doses also meet this criterion.

All other aspects of the original accident event and analysis, as presented in UFSAR Subsection 15.7.1, are unchanged. The proposed changes do not impact any accident initiators or assumed mitigation of accident or transient events. They do not involve the addition or removal of any equipment, or any design changes to the facility. There is no I

change to the types of efiluents released offsite. The source terms in UFSAR Table

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15e7-2 are unaffected. The change affects only the post-accident dose; there is no impact  ;

on individual or cumulative occupational radiation exposure. Therefore, this request does j not involve a significant increase in the probability or consequences of an accident l previously evaluated.

2. Does the change create the possibility of a new or different kind of accident from l any accident previously evaluated?

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The proposed changes do not involve a modification to the physical configuration of the  !

plant (i.e. no new equipment will be installed) or change in the methods governing normal i plant operation. The proposed changes will not impose any new or different requirements  !

or introduce a new accident or malfunction mechanism. The proposed change afTects only a calculation to determine dose following an event that has been previously analyzed. It l

has no impact on any event in the accident sequence, and no new failures are created.

l Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any previously evaluated.

l 3. Does the change involve a significant reduction in a margin of safety?  !

The proposed changes do not result in any reduction in the margin of safety because they .

i have no impact on safety analysis assumptions. Technical Specification 3.11.2.6 restricts l l the quantity of radioactivity contained in each gas storage tank to proside assurance that, in the event of an uncontrolled release of the tank's contents, the resulting whole body exposure will not exceed 0.5 rem, as established in BTP ETSB 11-5. The gas decay tank activity is limited to 50,000 curies of noble gas as Xe-133 equivalent. Since this activity ,

limit is not afTected and the calculated dose is less than 0.5 rem, the margin of safety  ;

remains the same.

l Therefore, based upon the above evaluation, Commonwealth Edison has concluded that these changes involve no significant hazards considerations.

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ATTACIIMENT D ENVIRONMENTAL ASSESSMENT FOR PROPOSED CIIANGES TO TIIE BYRON /BRAIDWOOD UFSAR Commonwealth Edison Company (Comed) has evaluated this proposed license amendment request against the criteria for identification oflicensing and regulatory actions requiring environmental assessment in accordance with Title 10, Code of Federal Regulations, Part 51, Section 21 (10 CFR 51.21). Comed has determined that this proposed license amendment request meets the criteria for a categorical exclusion set fonh in 10 CFR 51.22(c)(9). This determination is based on the fact that this change is being proposed as an amendment to a license issued pursuant to 10 CFR 50 that changes a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or that changes an inspection or a surveillance requirement, and the amendment meets the following specific criteria:

(i) the amendment involves no significant hazards considerations As demonstrated in Attachment C, this proposed amendment does not involve any significant hazards considerations.

(ii) there is no significant change in the types or significan; increase in the amounts of any effluent that may be released ofTsite As documented in Attachment C, there will be no change in the types or significant increase in the amounts of any efiluents released offsite.

(iii) there is no significant increase in individual or cumulative occupational radiation exposure.

The proposed changes will not result in changes in the operation or configuration of the facility. There will be no change in the level of controls or methodology used for processing of radioactive efiluents or handling of solid radioactive waste, nor will the proposal result in any change in the normal radiation levels within the plant. Although dose increases slightly, the change is not significant with respect to 10 CFR 100 limits. Therefore, there will be no increase in individual or cumulative occupational radiation exposure resulting from this change.

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