ML18102A472

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Calculation That Determines Radiation Doses at Eab,Lpz & in CR Following LOCA W/Modified Control Room Ventilation
ML18102A472
Person / Time
Site: Salem  PSEG icon.png
Issue date: 10/17/1996
From:
STONE & WEBSTER, INC.
To:
Shared Package
ML18102A471 List:
References
004-1, 4-1, NUDOCS 9610250076
Download: ML18102A472 (10)
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Text

-STONE & WEBSTER ENGINEERING CO.RATION

  • 5010.69 CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 6 of 53 02560 UR(B) 004 - 1 N/A 1.0 Objective The objective of this calculation is to determine the radiation doses at the Exclusive Area Boundary (EAB) , the Low Population Zone (LPZ), and in the Control Room (CR) following a Large Break Loss of Coolant Accident (LOCA) with the modified control room ventilation system. The calculation ass*umes a simultaneous Loss of Offsite Power (LOOP) following the control room isolation signal generated by the Safety Injection System, with the subsequent delay in switching from the normal operation mode to the emergency operation mode of the control. room ventilation system. The calculation utilizes the automatic selection*;

capability of the SI to select the less contaminated CR intake.

In addition, it assumes that only one Unit's CR emergency ventilation system is available.

Additionally, control room operator doses are also calculated for a case that assumes the control room is already in the emergency ventilation mode when the accident occurs.

- - 96fo2soo76 961017 PDR ADOCK 05000272 p PDR

.TONE & WEBSTER ENGINEERING CO.ATION

  • 5010.65' CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 15 of 53 02560 UR(B) 004 - 1 NIA 3.0 Assumptions
1.
  • Delay time for the CR pressurization mode to be fully operational - 48 seconds The normal intake damper closure time is assumed to be 20 seconds (Ref. [1] ) . The Loss Of Off site Power (LOOP) is assumed to occur at the time the dampers are fully closed and the power to the EACS fans are lost. At the LOOP, the Diesel Generators start and it takes 13 seconds(Ref. [1])

for the DG's to become fully operational and the power is delivered to the EACS fans. The EACS fans are assumed to take 15 seconds (Ref_ [1] ) to gain full speed and the control room is considered fully pressurized at this time.;

Therefore, the total delay time from the issuance of the safety injection signal until the control room is in recirculation mode is the sum of normal intake damper closure time (20 sec), the Diesel Generator speedup time (13 sec), and the EACS fans speedup time (15 sec) for a total of 48 seconds.

2. No credit is taken for iodine removal due to recirculation sprays. It is conservatively assumed that the sprays terminate at 48 minutes (i.e., after the injection phase).
3. The unfiltered inleakage after the CR is pressurized due to ingress/egress is assumed to be 10 cfm [Ref.l], based on SRP 6.4. The Unfiltered inleakage after the CR is pressurized due to ductwork is assumed to be 50 cfm [Ref.l].
4. The time for the control room EACS fans to reach full speed after restart is assumed to be 15 seconds [Ref.l].
5. It is assumed that the CR can be maintained at (+)1/8" W.G.

with a makeup flow of 2000 cfm.

.TONE & WEBSTER ENGINEERING coAATION

  • 5010.65 I CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.0.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 16 of 53 02560 UR(B) 004 - 1 N/A
1. Fraction of airborne core inventory available [Ref .1) for release from containment:

Halogen 25%

Noble Gas - 100%

The above assumes that 50% of the iodines released to the containment instantaneously plate out.

2. Iodine compositions in containment: [Ref. l]

Pre-existing RCS technical specification activity Elemental- 100%

Melted/Failed Fuel Activity Elemental - 91%

Organic 4%

Particulate 5%

3. Fraction of core inventory released to [Ref. 1]

sump: Halogen - 50%

4. Composition of iodine released [Ref .1]

from sump water: - Elemental

5. Volume of containment: 2,600,000 ft3 [Ref. l]
6. Volume of containment air released before [Ref .1]

isolation (via vacuum relief line) : 1014 ft3

7. Duration of Vacuum Relief Valve release: 5 sec [Ref. 1]

-TONE & WEBSTER ENGINEERING CO.ATION

  • 5010.65 CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 17 of 53 02560 UR(B) 004 - 1 N/A
8. Containment leak rate after isolation 0 to 1 day 0.1% vol fraction/day [Ref .1]

1 to 30 day - 0.05% vol fraction/day

9. Spray Initiation Time: 90 sec [Ref. 1]

Spray Cutoff Time: 48 min

10. Fraction of Containment Sprayed: 60% [Ref. 5]
11. Iodine Spray Removal Lambda [Ref. 1]

Elemental 20 hr- 1 Particulate - 6. 7 hr- 1 Methyl O hr- 1

12. Maximum iodine DFs from sprays and [Ref. 1]

and settling: 100

13. Flow from sprayed region to unsprayed [Ref. l]

region: 117,000 cfm (Based on 3 of 5 recirc fans operational/available at 39,000 cfm. Also see Appendix II)

.14. Volume of sump water: 295,000 gal [Ref. l]

15. ESF leakage parameters [Ref .1]

leakage rate - 3840 cc/hr partition fraction of leakage - 0.1 duration of leakage - 18 min. to 30 days leakage safety multiplier -2 fraction of leakage filtered - 50%

initiation time of ESF filters - 2 hrs filter efficiency - 90%

-TONE & WEBSTER ENGINEERING COR.RATION

  • 501,0.65' CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 18 of 53 02560 UR(B) 004 - 1 N/A
16. CONTROL ROOM PARAMETERS - Modified de.sign [Ref.1]
  • Control room pressure envelope volume:

81,420 ft 3

  • Control Room Normal Operation & EACS Vent System margin:

10%

  • Normal unfiltered air intake rate:

design value: 1200 cfm with margin: 1320 cfm

  • Filtered emergency makeup flow:

design value: 2000 cfm with margin: 2200 cfm

  • Total unfiltered inleakage- 60 cfm (10 cfm from ingress/egress; 50 cfm from ductwork leakage)
  • Filtered recirculation flow rate

- one EACS fan operation design value: total EACS flow = 8000 cfm design value: recirc = 8000-2000 = 6000 cfm with margin: total EACS flow = 7200 cfm with margin: recirc = 7200-2200 = 5000 cfm

- two EACS fans operation ++

design value: total EACS flow = 16000 cfm design value: recirc = 16000-2000 = 14000 cfm with margin: total EACS flow = 14400 cfm with margin: recirc = 14400-2200 = 12200 cfm

  • Intake and recirculating filter efficiencies:

Elemental iodine - 95%

Organic iodine - 95%

Particulate - 95%

-TONE & WEBSTER ENGINEERING CO.ATION

  • 5010.65 CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 19 of 53 02560 UR(B) 004 . 1 N/A
  • Control room occupancy factors: [Ref. 7]

Time from Start Occupancy of Accident Factors O to 8 hrs 1. 0 8 to 24 hrs 1. 0 1 to 4 days 0.6 4 to 30 days 0.4

  • Breathing rate - 3.47E-4 m3 /sec [Ref. 1]
17. Control room intake X/Q's [Ref. 1]

(from Unit 1 Main Vent, which has worse x/Qs than unit 2 main vent)

Unit 1 intake Unit 2 intake (SLm 3 ) (s Lm3 )

0-2 hr 1.72E-3 8.90E-4 2-8 hr 1.22E-3 6.35E-4 8-24 hr 1.03E-3 5.36E-4 1-4 day 7.13E-3 3.72E-4 4-30day 4.19E-4 2.20E-4

18. Off site Breathing rate [Ref .1]

0 - 8 hr - 3.47E-4 m3 /sec 8 - 24 hr - 1. 75E-4 m3 /sec 24- 720 hr - 2.32E-4 m3 /sec

19. Off site X/Q's (from all plant release points) [Ref .1] .

EAB LPZ rn Lm 3 l (SLm3 )

0-2 hr 1.30E-4 1.86E-5 2-8 hr 7.76E-6 8-24 hr 5.0lE-6 1-4 day 1. 94E-6 4-30day 4.96E-7

-TONE & WEBSTER ENGINEERING CO-RATION

  • 5010.65, CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 20 of 53 02560 UR(B) 004 . 1 N/A
20. The core activities are presented below: [Ref. 1]

100% of the noble gases and 25% of the halogens noted below are available for release from the containment atmosphere Core Inventory (x 10 7 Ci)

Nuclide Activit~ Nuclide Activit~

Kr85m 2.6 1131 9.9 I Kr85 0.11 1132 14.

Kr87 4.7 1133 20.

Kr88 6.7 1134 '22.

Xe131m 0.07 1135 19.

Xe133m 2.9 Xe133 20.

Xe135m 4.

Xe135 5.

Xe138 16.

-STONE & WEBSTER ENGINEERING COf.RATION

  • 501.0.65' CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 21 of 53 02560 UR(B) 004 . 1 N/A
21. Initial Coolant Activity Including [Ref. 1) a Pre-accident Iodine Spike. [The noble gas activity is based on 1% fuel defects, the iodine activity is based on 60µCi/gm Dose Equivalent I-131]

RCS Activity (Ci)

Nu~lige A~tiv;i,t:j!'. Nu~lid~ Activit:j!'.

Kr85m 4.4E2 Il31 l.04E4 ,

Kr85 2.1E3 Il32 3.58E3 Kr87 2.6E2 Il33 l.60E4 Kr88 7.8E2 Il34 2.02E3 Xe13lm 5.4E2 Il35 8.08E3 Xel33m 4.4E3 Xel33 6.7E4 Xel35m l.3E2 Xel35 2.2E3 Xel38 l.6E2 5.0 Summary of Required Confirmation

~ Two thousand (2000) cfm CR emergency makeup flow.

~ Fifty (50) cfm unfiltered inleakage after the control room is pressurized.

~ Fifteen (15) second ramp up time for CR EACS fans.

-TONE & WEBSTER ENGINEERING COR-ATION

  • 5010.65 CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 52 of 53 02560 UR(B) 004 - 1 N/A 8.0 Results and Conclusions The calculated doses (rem) at the Salem Generating Station EAB, LPZ and control room from a postulated Large Break LOCA are:

SITE BOUNDARY Location Thyroid Whole Body EAB 22.5 0.8 LPZ 8.6 0.2 The exposure guidelines at the EAB and LPZ set forth in 10CFRlOO are 300 rem thyroid and 25 rem whole body. The calculated doses at the EAB and LPZ, are well within the 10CFRlOO exposure guidelines.

CONTROL ROOM CASE 1: Selection of Favorable IntakeO Thyroid 28 .4 rem Whole Body 1.7 rem Beta Skin 12.3 rem 0 Values reflect automatic selection of the control room favorable intake with only one unit EACS operating.

-TONE & WEBSTER ENGINEERING CO.ATION

  • 5010.65, CALCULATION SHEET CALCULATION IDENTIFICATION NUMBER J.O.OR W.O.NO. DIVISION & GROUP CALCULATION NO. OPTIONAL TASK CODE 53 of 53 02560 UR(B) 004 - 1 N/A CASE 2: Pre-Existing Emergency Mode@

Thyroid 25.0 rem Whole Body 3.1 rem Beta Skin 22.7 rem

$ Assumes worst case control room intake but that the CR EACS for both units are operational The exposure guideline in the control room set forth in 10CFRSO; General Design Criteria 19 is 5 rem to the Whole body or its organ dose equivalent (accepted as 30 rem to the thyroid from inhalation and 30 rem beta from submersion) The calculated doses in the control room are within the 10CFRSO exposure guidelines.

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