ML17340B106
| ML17340B106 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 12/13/2017 |
| From: | Cavedo R Exelon Generation Co, Nuclear Energy Institute |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17340B096 | List: |
| References | |
| Download: ML17340B106 (9) | |
Text
Reduction in the NSP Floor Rob Cavedo
Potential Realism Improvement Reduction in the NSP Floor 1
The NSP Floor is at 1-in-1000 for an infinite duration fire.
This can be a significant contributor to control room abandonment likelihoods with lower heat release rate scenarios.
Identification of Relevant Guidance Reduction in the NSP Floor 2
The guidance in NUREG/CR-6850 Supplement 1 Table 14-1 states that a value of no lower 1E-3 should be used for NSP likelihood regardless of how much time is available until target damage.
Update Results from NUREG 2169 follow the same approach:
Proposed Approach to Enhance Realism Reduction in the NSP Floor 3
The fire brigade composition and method of operation is similar to a reactor operational response crew.
There is a leader directing the actions of the fire brigade members. The leader will bring more and more resources to bear as the scenario progresses.
Proposed Approach to Enhance Realism - Limitation Reduction in the NSP Floor 4
This will effectively apply only to small fire scenarios. Large fire scenarios will have short times to damage which will have NSP already above the 1E-3 Floor.
Sample Curve Changes Reduction in the NSP Floor 5
0.324 0.111 0.098 Time NSP with Floor 1E-3 NSP with Floor 1E-5 Time NSP with Floor 1E-3 NSP with Floor 1E-5 Time NSP with Floor 1E-3 NSP with Floor 1E-5 0
1 1
0 1
1 0
1 1
5 0.198 0.198 5
0.57 0.57 5
0.61 0.61 10 0.039 0.039 10 0.33 0.33 10 0.38 0.38 15 0.0077 0.0077 15 0.19 0.19 15 0.23 0.23 20 1.52E-03 1.52E-03 20 0.11 0.11 20 0.14 0.14 25 1.00E-03 3.01E-04 25 0.06 0.06 25 0.09 0.09 30 1.00E-03 5.95E-05 30 0.04 0.04 30 0.05 0.05 35 1.00E-03 1.18E-05 35 0.02 0.02 35 0.03 0.03 40 1.00E-03 1.00E-05 40 0.01 0.01 40 0.02 0.02 50 1.00E-03 1.00E-05 50 3.81E-03 3.81E-03 50 7.63E-03 7.63E-03 60 1.00E-03 1.00E-05 60 1.25E-03 1.25E-03 60 2.88E-03 2.88E-03 70 1.00E-03 4.11E-04 70 1.08E-03 1.08E-03 80 1.00E-03 1.35E-04 80 1.00E-03 4.09E-04 90 1.00E-03 4.42E-05 90 1.00E-03 1.54E-04 100 1.00E-03 1.45E-05 100 1.00E-03 5.82E-05 110 1.00E-03 1.00E-05 110 1.00E-03 2.19E-05 120 1.00E-03 1.00E-05 120 1.00E-03 1.00E-05 Control Room Transients Electrical Fires
Control Room Abandonment Improvement (w NUREG 2178)
Reduction in the NSP Floor 6
The reduction of the floor can provide a 20% to 50% reduction in the likelihood of control room abandonment. The benefit is on larger side for control room modeling that credits NUREG 2178 which has a much higher likelihood of lower HRR fires.
Bin, i HRR (kW)
SF Time To Abandonment NSP wo Floor SF*NSP wo Floor Contribution wo Floor NSP with Floor SF*NSP with Floor Contribution with Floor 1
34 0.161 33 2.27E-05 3.65E-06 0.65%
1.00E-03 1.61E-04 14.0%
2 130 0.554 25 3.04E-04 1.68E-04 30.05%
1.00E-03 5.54E-04 48.5%
3 221 0.205 22 8.02E-04 1.64E-04 29.38%
1.00E-03 2.05E-04 17.9%
4 310 0.059 19.1 2.05E-03 1.22E-04 21.71%
2.05E-03 1.22E-04 10.6%
5 400 1.61E-02 17.25 3.74E-03 6.00E-05 10.72%
3.74E-03 6.00E-05 5.3%
6 490 4.03E-03 15.67 0.0062 2.51E-05 4.49%
0.0062 2.51E-05 2.2%
7 579 9.72E-04 13.8 0.0114 1.11E-05 1.99%
0.0114 1.11E-05 1.0%
8 669 2.35E-04 12.59 0.0169 3.98E-06 0.71%
0.0169 3.98E-06 0.35%
9 759 5.47E-05 11.82 0.0217 1.19E-06 0.21%
0.0217 1.19E-06 0.10%
10 848 1.25E-05 11.3 0.0257 3.21E-07 0.06%
0.0257 3.21E-07 0.03%
11 938 2.90E-06 10.76 0.0306 8.88E-08 1.59E-04 0.0306 8.88E-08 7.77E-05 12 1,028 6.53E-07 10.46 0.0337 2.20E-08 3.94E-05 0.0337 2.20E-08 1.93E-05 13 1,118 1.46E-07 10.01 0.0390 5.71E-09 1.02E-05 0.0390 5.71E-09 4.99E-06 14 1,208 3.25E-08 9.68 0.0434 1.41E-09 2.53E-06 0.0434 1.41E-09 1.24E-06 15 1,462 9.24E-09 8.64 0.0608 5.62E-10 1.00E-06 0.0608 5.62E-10 4.92E-07 Pr(ab) 5.60E-04 Pr(ab) 1.14E-03
Industry Benefit Reduction in the NSP Floor 7
The maximum site benefit is about 10% reduction in CDF/LERF. The average industry benefit is about 5% reduction in CDF/LERF
Questions Moving towards more Realistic Cabinet Damage 8