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{{#Wiki_filter:BFN-18  TABLE 14.9-1   DESIGN BASIS ACCIDENT RADIOLOGICAL DOSES  (REM)                                        WHOLE BODY                                THYROID 2 hour          30 day                2 hour              30 day Accident                        (1400 m)        (3218 m)              (1400 m)          (3218 m)  Loss of Coolant 2.2 x 10-1 6.1 x 10-1    2.9 x 100      3.6 x 101  Refueling 4.9 x 10-2 1.9 x 10-2    3.1 x 101      4.2 x 10-1  Control Rod Drop 1.2 x 10-2 4.3 x 10-2    6.1 x 100      7.0 x 100  Steam Line Break 1.7 x 10-2 8.0 x 10-3    3.0 x 101      1.0 x 101 BFN-18  Table 14.9-2  (Sheet 1)  SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS  LOSS-OF-COOLANT ACCIDENT Factor Affecting                                  Design "Base"                        Assumed AEC  Assumptions                          Case                                Case                    Thyroid Dose            Whole Body Dose  Fission products              1.8 percent noble gases1  100 percent noble gases              625                      220 released to drywell          0.32 percent iodines                  50 percent iodines and                              from 25 percent of the          1 percent solids in                                fuel rods which are                  total core inventory.                              assumed to be perforated. 5 percent of total                              1 percent of total iodine          iodines in organic form.
{{#Wiki_filter:BFN-18  TABLE 14.9-1 DESIGN BASIS ACCIDENT RADIOLOGICAL DOSES  (REM)                                        WHOLE BODY                                THYROID  
in organic form. Negligible                              solids. Iodine retained              Based on partition factor  None                                  12.53                      1 in water                      of 100 between the volumes                              of air and water in                              pressure suppression chamber                                and drywell.


Elemental iodine              50 percent                            50 percent                              1                        1 plateout in drywell   Leakage rate from    Function of drywell                  0.635 percent volume per                1.3 (2-hr)2              1.3 (2-hr) primary containment    pressure; peaks close  day, constant                          ~1 (30-day)                ~(30-day)                            to 0.5 percent volume throughout accident  per day Uniform mixing                Yes                                  No                                    22 (2-hr)                28 (2-hr) in Reactor Building                                                  1.2 (30-day)                    1.1 (30-day)
2 hour          30 day                2 hour              30 day Accident                        (1400 m)        (3218 m)              (1400 m)          (3218 m)
Iodine filter                99 percent                            90 percent                            10                        1 efficiency  (95 percent for solids) Effectiveness of stack  Yes                                  Yes                                    1                        1  NOTE:  11 percent of iodines released in organic form, which is not reduced by fallout or drywell and reactor building. Elemental iodines are  carried into pressure suppression pool during blowdown, and a fraction retained according to the assumed equilibrium partition factor of 100. Iodines become airborne in the pressure suppression chamber and drywell before leaking out to the secondary containment. 22-hr dose is evaluated at site boundary of 1400 meters; 30-day dose is evaluated at low-population zone of 3218 meters. 3Takes into account the organic iodine fraction.
Loss of Coolant 2.2 x 10
BFN-18  Table 14.9-2 (Sheet 2)                       SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS   
-1 6.1 x 10
-1    2.9 x 10 0      3.6 x 10 1  Refueling 4.9 x 10
-2 1.9 x 10
-2    3.1 x 10 1      4.2 x 10
-1  Control Rod Drop 1.2 x 10
-2 4.3 x 10
-2    6.1 x 10 0      7.0 x 10 0  Steam Line Break 1.7 x 10
-2 8.0 x 10
-3    3.0 x 10 1      1.0 x 10 1
BFN-18  Table 14.9-2 (Sheet 1)
SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS  LOSS-OF-COOLANT ACCIDENT
 
Factor Affecting Design "Base"                        Assumed AEC  Assumptions                          Case                                Case                    Thyroid Dose            Whole Body Dose Fission products              1.8 percent noble gases 1  100 percent noble gases              625                      220 released to drywell          0.32 percent iodines                  50 percent iodines and                              from 25 percent of the          1 percent solids in                                fuel rods which are                  total core inventory.                              assumed to be perforated. 5 percent of total                              1 percent of total iodine          iodines in organic form.
in organic form. Negligible                              solids.
Iodine retained              Based on partition factor  None                                  12.5 3                      1 in water                      of 100 between the volumes                              of air and water in                              pressure suppression chamber                                and drywell.
 
Elemental iodine              50 percent                            50 percent                              1                        1 plateout in drywell Leakage rate from    Function of drywell                  0.635 percent volume per                1.3 (2-hr) 2              1.3 (2-hr) primary containment    pressure; peaks close  day, constant                          ~1 (30-day)                ~(30-day)                            to 0.5 percent volume throughout accident  per day Uniform mixing                Yes                                  No                                    22 (2-hr)                28 (2-hr) in Reactor Building                                                  1.2 (30-day)                    1.1 (30-day)  
 
Iodine filter                99 percent                            90 percent                            10                        1 efficiency  (95 percent for solids)
Effectiveness of stack  Yes                                  Yes                                    1                        1  NOTE:  11 percent of iodines released in organic form, which is not reduced by fallout or drywell and reactor building. Elemental iodines are  carried into pressure suppression pool during blowdown, and a fraction retained according to the assumed equilibrium partition factor of 100. Iodines become airborne in the pressure suppression chamber and drywell before leaking out to the secondary containment.
22-hr dose is evaluated at site boundary of 1400 meters; 30-day dose is evaluated at low-population zone of 3218 meters.
3Takes into account the organic iodine fraction.
BFN-18  Table 14.9-2
 
(Sheet 2)
SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS   


REFUELING ACCIDENT  
REFUELING ACCIDENT  


Factor Affecting  Design "Base"                        Assumed AEC  Assumptions                          Case                                Case                    Thyroid Dose            Whole Body Dose Fission product              1.8 percent noble gases,              20 percent noble gases,              13.8  4.9 release to reactor          0.32 percent iodines from            10 percent iodines from water1                      111 perforated fuel                  49 perforated fuel                              rods, solids negligible              rods2 Iodines retained            Equilibrium partition4               90 percent2                           0.4  1 in water                    factor of 100 for iodines and water  
Factor Affecting  Design "Base"                        Assumed AEC  Assumptions                          Case                                Case                    Thyroid Dose            Whole Body Dose Fission product              1.8 percent noble gases,              20 percent noble gases,              13.8  4.9 release to reactor          0.32 percent iodines from            10 percent iodines from water1                      111 perforated fuel                  49 perforated fuel                              rods, solids negligible              rods 2 Iodines retained            Equilibrium partition 4               90 percent 2                           0.4  1 in water                    factor of 100 for iodines and water  


Plateout of iodines          None                                  50 percent                            0.5  1 in Reactor Building Uniform mixing in            Yes                                  No                                    14 (2-hr)3  18 (2-hr) refueling chamber                                                                                      ~1.3 (30-day)  ~1.1 (30-day)
Plateout of iodines          None                                  50 percent                            0.5  1 in Reactor Building Uniform mixing in            Yes                                  No                                    14 (2-hr) 3  18 (2-hr) refueling chamber                                                                                      ~1.3 (30-day)  ~1.1 (30-day)
Fission Products                      Fission products                              exponentially released                exponentially released                              from water to Reactor                from water in 2 hours                              Building till exhausted  
Fission Products                      Fission products                              exponentially released                exponentially released                              from water to Reactor                from water in 2 hours                              Building till exhausted  


Line 34: Line 58:
Effectiveness of            Yes                                  Yes                                    1  1 stack   
Effectiveness of            Yes                                  Yes                                    1  1 stack   


NOTE:  1Accident occurs 24 hours after shutdown. 2Assumptions in Hatch (Docket No. 50.321) evaluation. 32-hr dose is evaluated at site boundary of about 1400 meters. 30-day dose is evaluated at low-population zone of 3128 meters. 4Amount of retention depends on the ratio of air space to water space. In this case, the equivalent value of 75 percent is obtained.
NOTE:  1Accident occurs 24 hours after shutdown.
BFN-18  Table 14.9-2 (Sheet 3)                       SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS CONTROL ROD DROP ACCIDENT  
2Assumptions in Hatch (Docket No. 50.321) evaluation.
32-hr dose is evaluated at site boundary of about 1400 meters. 30-day dose is evaluated at low-population zone of 3128 meters.
4Amount of retention depends on the ratio of air space to water space. In this case, the equivalent value of 75 percent is obtained.
BFN-18  Table 14.9-2
 
(Sheet 3)
SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS CONTROL ROD DROP ACCIDENT
 
Factor Affecting                  Design "Base"                        Assumed AEC  Assumptions                        Case                                Case                    Thyroid Dose            Whole Body Dose Fission products          1.8 percent noble gases,                100 percent noble gases,            156                        55 released to water          0.32 percent iodines from              50 percent iodines from                            330 perforated fuel                    330 perforated rods, solids negligible                fuel rods Noble gases carry-        Uniformly mixed with                    100 percent                            1                        10 over to condenser          steam, carried over hotwell                    at 5.0 percent steam flow rate, isolation valve closure at 10.5 sec.
 
Iodine carryover to        Retention in water, 1                    10 percent                          2700                        1.0 condenser hotwell          uniform mixing in steam dome, carryover at 5.0 percent steam flow, and isolation at 10.5 seconds Iodine plateout in        None                                    50 percent                            0.5                        1 condenser hotwell
 
Release mechanism          1800 cfm from vapor                    Leak rate of 0.5 percent per        5.5 X 10
-4 (2-hrs)        5.5 X 10
-4 (2-hrs)                            space of condenser and                  day from condenser              1.13 X 10
-2 (30-days)      1.13 X 10
-2 (30-days)                            turbine, stack release                  to environs
 
NOTE:
1Amount of retention in condenser hotwell water depends on relative ratio of steam space to water space. The "base"  case uses an equilibrium partition factor of 100 and a    steam-water space ratio of about 12.
 
BFN-18  Table 14.9-2 
 
(Sheet 4)
SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS STEAM LINE BREAK ACCIDENT  


Factor Affecting                   Design "Base"                        Assumed AEC  Assumptions                       Case                                Case                    Thyroid Dose            Whole Body Dose  Fission products           1.8 percent noble gases,               100 percent noble gases,             156                       55 released to water          0.32 percent iodines from              50 percent iodines from                            330 perforated fuel                    330 perforated rods, solids negligible                fuel rods  Noble gases carry-        Uniformly mixed with                    100 percent                            1                       10 over to condenser          steam, carried over hotwell                    at 5.0 percent steam flow rate, isolation valve closure at 10.5 sec.
Factor Affecting                       Design "Base"                        Assumed AEC  Assumptions                   Case                                Case                    Thyroid Dose            Whole Body Dose  Steam and Water           185,000 lb                              185,000 lb                       1                         1 Mass Lost in              (25,000 lb steam blowdown (10.5           160,000 lb water) sec. closure)
Iodine carryover to       Retention in water,1                    10 percent                          2700                        1.0 condenser hotwell          uniform mixing in steam dome, carryover at 5.0 percent steam flow, and isolation at 10.5 seconds  Iodine plateout in        None                                    50 percent                            0.5                        1 condenser hotwell
Total fission            146 curies iodines                      Proportional to                 10.5                      10
.52 gases released            and 5.7 curies                          operating limit,                           noble gases 1 10.5 times the                                                                  base case value


Release mechanism         1800 cfm from vapor                    Leak rate of 0.5 percent per        5.5 X 10-4 (2-hrs)        5.5 X 10-4 (2-hrs)                            space of condenser and                 day from condenser              1.13 X 10-2 (30-days)      1.13 X 10-2 (30-days)                            turbine, stack release                  to environs NOTE:
Concentration in         Equilibrium separation                 Equilibrium separation            1                         1 water and steam  
1Amount of retention in condenser hotwell water depends on relative ratio of steam space to water space. The "base"  case uses an equilibrium partition factor of 100 and a    steam-water space ratio of about 12.
BFN-18  Table 14.9-2 (Sheet 4)                        SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS  STEAM LINE BREAK ACCIDENT 


Factor Affecting                      Design "Base"                        Assumed AEC  Assumptions                    Case                                Case                    Thyroid Dose            Whole Body Dose  Steam and Water          185,000 lb                              185,000 lb                        1                        1 Mass Lost in              (25,000 lb steam blowdown (10.5            160,000 lb water) sec. closure)  Total fission            146 curies iodines                      Proportional to                  10.5                      10.52 gases released            and 5.7 curies                          operating limit,                          noble gases1 10.5 times the                                                                  base case value
Steam cloud rise          No                                      No                                1                        1


Concentration in          Equilibrium separation                  Equilibrium separation            1                        1 water and steam Steam cloud rise          No                                      No                                1                        1 NOTE:
NOTE:
1Based on fission product concentrations in coolant such that the offgas release rate at stack reaches the maximum expected value of 10,000 FCi/sec. 2In the steamline break accident, the noble gases contribution to the whole body dose is insignificant.}}
1Based on fission product concentrations in coolant such that the offgas release rate at stack reaches the maximum expected value of 10,000 FCi/sec.
2In the steamline break accident, the noble gases contribution to the whole body dose is insignificant.}}

Revision as of 05:13, 29 June 2018

Browns Ferry Nuclear Plant Updated Final Safety Analysis Report (Ufsar), Amendment 27, 14.9 Table - Dose Sensitivity Evaluation
ML18024A349
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Issue date: 10/05/2017
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Text

BFN-18 TABLE 14.9-1 DESIGN BASIS ACCIDENT RADIOLOGICAL DOSES (REM) WHOLE BODY THYROID

2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 30 day 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 30 day Accident (1400 m) (3218 m) (1400 m) (3218 m)

Loss of Coolant 2.2 x 10

-1 6.1 x 10

-1 2.9 x 10 0 3.6 x 10 1 Refueling 4.9 x 10

-2 1.9 x 10

-2 3.1 x 10 1 4.2 x 10

-1 Control Rod Drop 1.2 x 10

-2 4.3 x 10

-2 6.1 x 10 0 7.0 x 10 0 Steam Line Break 1.7 x 10

-2 8.0 x 10

-3 3.0 x 10 1 1.0 x 10 1

BFN-18 Table 14.9-2 (Sheet 1)

SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS LOSS-OF-COOLANT ACCIDENT

Factor Affecting Design "Base" Assumed AEC Assumptions Case Case Thyroid Dose Whole Body Dose Fission products 1.8 percent noble gases 1 100 percent noble gases 625 220 released to drywell 0.32 percent iodines 50 percent iodines and from 25 percent of the 1 percent solids in fuel rods which are total core inventory. assumed to be perforated. 5 percent of total 1 percent of total iodine iodines in organic form.

in organic form. Negligible solids.

Iodine retained Based on partition factor None 12.5 3 1 in water of 100 between the volumes of air and water in pressure suppression chamber and drywell.

Elemental iodine 50 percent 50 percent 1 1 plateout in drywell Leakage rate from Function of drywell 0.635 percent volume per 1.3 (2-hr) 2 1.3 (2-hr) primary containment pressure; peaks close day, constant ~1 (30-day) ~(30-day) to 0.5 percent volume throughout accident per day Uniform mixing Yes No 22 (2-hr) 28 (2-hr) in Reactor Building 1.2 (30-day) 1.1 (30-day)

Iodine filter 99 percent 90 percent 10 1 efficiency (95 percent for solids)

Effectiveness of stack Yes Yes 1 1 NOTE: 11 percent of iodines released in organic form, which is not reduced by fallout or drywell and reactor building. Elemental iodines are carried into pressure suppression pool during blowdown, and a fraction retained according to the assumed equilibrium partition factor of 100. Iodines become airborne in the pressure suppression chamber and drywell before leaking out to the secondary containment.

22-hr dose is evaluated at site boundary of 1400 meters; 30-day dose is evaluated at low-population zone of 3218 meters.

3Takes into account the organic iodine fraction.

BFN-18 Table 14.9-2

(Sheet 2)

SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS

REFUELING ACCIDENT

Factor Affecting Design "Base" Assumed AEC Assumptions Case Case Thyroid Dose Whole Body Dose Fission product 1.8 percent noble gases, 20 percent noble gases, 13.8 4.9 release to reactor 0.32 percent iodines from 10 percent iodines from water1 111 perforated fuel 49 perforated fuel rods, solids negligible rods 2 Iodines retained Equilibrium partition 4 90 percent 2 0.4 1 in water factor of 100 for iodines and water

Plateout of iodines None 50 percent 0.5 1 in Reactor Building Uniform mixing in Yes No 14 (2-hr) 3 18 (2-hr) refueling chamber ~1.3 (30-day) ~1.1 (30-day)

Fission Products Fission products exponentially released exponentially released from water to Reactor from water in 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Building till exhausted

Iodine filter 99 percent 90 percent 10 1 efficiency (95 percent for solids)

Effectiveness of Yes Yes 1 1 stack

NOTE: 1Accident occurs 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after shutdown.

2Assumptions in Hatch (Docket No. 50.321) evaluation.

32-hr dose is evaluated at site boundary of about 1400 meters. 30-day dose is evaluated at low-population zone of 3128 meters.

4Amount of retention depends on the ratio of air space to water space. In this case, the equivalent value of 75 percent is obtained.

BFN-18 Table 14.9-2

(Sheet 3)

SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS CONTROL ROD DROP ACCIDENT

Factor Affecting Design "Base" Assumed AEC Assumptions Case Case Thyroid Dose Whole Body Dose Fission products 1.8 percent noble gases, 100 percent noble gases, 156 55 released to water 0.32 percent iodines from 50 percent iodines from 330 perforated fuel 330 perforated rods, solids negligible fuel rods Noble gases carry- Uniformly mixed with 100 percent 1 10 over to condenser steam, carried over hotwell at 5.0 percent steam flow rate, isolation valve closure at 10.5 sec.

Iodine carryover to Retention in water, 1 10 percent 2700 1.0 condenser hotwell uniform mixing in steam dome, carryover at 5.0 percent steam flow, and isolation at 10.5 seconds Iodine plateout in None 50 percent 0.5 1 condenser hotwell

Release mechanism 1800 cfm from vapor Leak rate of 0.5 percent per 5.5 X 10

-4 (2-hrs) 5.5 X 10

-4 (2-hrs) space of condenser and day from condenser 1.13 X 10

-2 (30-days) 1.13 X 10

-2 (30-days) turbine, stack release to environs

NOTE:

1Amount of retention in condenser hotwell water depends on relative ratio of steam space to water space. The "base" case uses an equilibrium partition factor of 100 and a steam-water space ratio of about 12.

BFN-18 Table 14.9-2

(Sheet 4)

SENSITIVITY OF DOSES TO VARIATION OF ASSUMPTIONS STEAM LINE BREAK ACCIDENT

Factor Affecting Design "Base" Assumed AEC Assumptions Case Case Thyroid Dose Whole Body Dose Steam and Water 185,000 lb 185,000 lb 1 1 Mass Lost in (25,000 lb steam blowdown (10.5 160,000 lb water) sec. closure)

Total fission 146 curies iodines Proportional to 10.5 10

.52 gases released and 5.7 curies operating limit, noble gases 1 10.5 times the base case value

Concentration in Equilibrium separation Equilibrium separation 1 1 water and steam

Steam cloud rise No No 1 1

NOTE:

1Based on fission product concentrations in coolant such that the offgas release rate at stack reaches the maximum expected value of 10,000 FCi/sec.

2In the steamline break accident, the noble gases contribution to the whole body dose is insignificant.

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