ML042790504
| ML042790504 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 12/16/2003 |
| From: | Harper W Tennessee Valley Authority |
| To: | Higgins J Office of Nuclear Reactor Regulation, Tennessee Valley Authority |
| References | |
| Download: ML042790504 (10) | |
Text
Date:
December 16, 2003 From:
Walter Harper, LAB 2C-N To:
John Higgins, CST17B-C
Subject:
Browns Ferry Nuclear Plant Tower Usage and Load Reductions Under Proposed Increase in Reactor Power Levels and Unit 1 Restart
- John, I have run our simulation model for the period from January 1, 1969 through December 31, 2002, excluding the years 1989 and 1990. Two alternatives were evaluated, computing cooling tower usage and load reductions necessary to remain in compliance with all thermal standards and operating guidelines (turbine back-pressure).
Alternative 1 Units 2 and 3 are upgraded to 120% of design reactor power with no additional cooling tower capacity. The results of the Alternative 1 simulations are shown in Table 1 and Table 2.
Alternative 2 Units 1, 2, and 3 are upgraded to 120% of design reactor power, with one additional rectangular mechanical draft tower, built on the footprint of the original tower #4, bringing the total number of towers to six. The new tower would have design water and wet bulb temperatures similar to those of the current BFN cooling tower #3, but would have a 25% greater water flow rate. The results of the Alternative 2 simulations are shown in Table 3 and Table 4.
From this analysis, the net generation for Alternative 2 would be about 43% greater than the net generation for Alternative 1, 66% greater than the net generation for the current plant configuration (Table 5), and 16% greater than the net generation for the original plant configuration (Table 7).
Definitions of abbreviations/variable names for Safety/Operational limits:
bpmax - turbine backpressure limit (5.5 inches/hg) tcmax - maximum allowable intake temperature dtmmax - maximum allowable downstream river temperature rise tdsmax - maximum allowable downstream river temperature
Please note the following assumptions/conditions:
- 1. Maximum cooling tower lift pump flow rates of 289 cfs/pump for the older towers (#s 1,2,5, and 6) and 314 cfs/pump for the newer existing rectangular tower (#3) are based on estimates made by Marilyn Reeves (PEC 1A-BFN) in a phone conversation on 8/01/1999. This accounts for the necessary throttling of the pumps in the old towers to prevent overflow of structures within the towers. The new tower to be built under Alternative 2 is assumed to have a maximum cooling tower lift pump flow rate of 392.4 cfs/pump (25% greater than the existing tower #3).
- 2. The assumed tower capability of 80% for the old towers (1, 2, 5, and 6) is an average estimate based on historical operational data and single point measurements of tower effluent temperature received from Ray Swafford (PEC 2D-BFN) on 8/01/1999. Tower capabilities for tower #3 and the proposed tower #4 are set at 96%, based on the results of the thermal acceptance test of tower #3.
- 3. An "action level" of 89.0 °F was used for changes in cooling tower usage. When the computed 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> averaged downstream temperature reached 89.0 °F, additional lift pumps were turned on and/or additional unit(s) was placed on towers until the computed 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> averaged downstream temperature dropped below 89.0 °F. Towers were put in service in order of their cooling capacity, taking into account the reduced flow rates in the older towers, with the highest capacity towers being added first. If no additional tower operation was possible, no action was taken until one of the downstream thermal limits would be exceeded, at which point unit loads were reduced sufficiently to bring the downstream temperature within the thermal standards.
- 4. When load reductions were needed, unit loads were reduced on one unit at a time in 50 MWe increments until the thermal limits were met. If a unit was derated to below 440 MWe generation, it was shut down and derates began on the next unit. When a unit was shut down, its condenser cooling water (CCW) pumps remained in operation, but the units cooling water was sent directly to the diffusers instead of to the cooling towers. This allows the towers to cool the CCW flow from the remaining units more efficiently.
- 5. Note that a turbine backpressure limit of 5.5 inches Hg was used instead of the previously used value of 4.5 inches Hg. Early runs at the 120% power level indicated that significant load reduction would be needed to keep the turbine backpressure below 4.5 inch Hg.
Please call (865) 632-1882 if we can be of further assistance.
Walter Harper Mechanical Engineer River System Operations TVA Engineering Lab Norris, TN
Table 1. Load Reductions And Tower Usage For Units 2 And 3 At 120% Design Power Level With Existing Towers (Alternative 1)
Breakdown of Load Reductions and Tower Usage Number of Units: 2 Number of Towers: 5 Downstream Temperature Limit (24-hr avg): 90.0 Cooling Tower Capabilities: 80 80 96 80 80 Maximum Unit Reactor Power Levels (MWt): 0 3951 3951 Maximum Unit Loads (MWe): 0 1280 1280 Plant operation decisions based on 24 hr averaged downstream temperatures Maximum Unit Loads (MWe): 0 1280 1280 Column 1: year Column 2: Net generation (MW-hr)
Column 3: Cumulative hours of reduced load Column 4: Cumulative hours of cooling tower usage Column 5: Total load reductions & tower energy (Mw-Hr)
Column 6: Total (non-tower) load reductions (Mw-Hr)
Column 7: Number of cooling-tower-hours of required operation Column 8: Load reductions due to 24-hr tdsmax restriction Column 9: Load reductions due to dtmmax restriction Column 10: Load reductions due to 1-hr tdsmax restriction Column 11: Load reductions due to bpmax restriction Column 12: Load reductions due to tcmax restriction 1985 22067774 0
163 4319 0
633 0
0 0
0 0
1986 21969254 37 835 66328 39654 3787 39654 0
0 0
0 1987 22036764 0
430 13785 0
1956 0
0 0
0 0
1988 22120170 0
579 18137 0
2583 0
0 0
0 0
1991 22036116 0
500 15574 0
2220 0
0 0
0 0
1992 22173664 0
28 686 0
102 0
0 0
0 0
1993 21887302 74 808 171046 144436 3760 144436 0
0 0
0 1994 22085834 0
27 817 0
117 0
0 0
0 0
1995 22015690 0
737 23414 0
3327 0
0 0
0 0
1996 22137316 0
171 4923 0
711 0
0 0
0 0
1997 22097194 0
288 8664 0
1242 0
0 0
0 0
1998 22013868 0
473 15209 0
2157 0
0 0
0 0
1999 21944674 38 598 95303 76686 2654 76686 0
0 0
0 2000 22087050 0
599 18218 0
2607 0
0 0
0 0
2001 22063492 0
221 6932 0
987 0
0 0
0 0
2002 21992824 0
924 29244 0
4158 0
0 0
0 0
Total:
3.53E+08 149 7381 492599 260776 33001 260776 0
0 0
0
Table 2. Plant Shut Downs for Units 2 And 3 At 120% Design Power Level With Existing Towers (Alternative 1)
Breakdown of Plant Shut Downs Number of Units: 2 Number of Towers: 5 Downstream Temperature Limit (24-hr avg): 90.0 Cooling Tower Capabilities: 80 80 96 80 80 Maximum Unit Reactor Power Levels (MWt): 0 3951 3951 Maximum Unit Loads (MWe): 0 1280 1280 Plant operation decisions based on 24 hr averaged downstream temperatures Column 1: year Column 2: shut downs due to 24-hr tdsmax restriction Column 3: shut downs due to dtmmax restriction Column 4: shut downs due to 1-hr tdsmax restriction Column 5: shut downs due to bpmax restriction Column 6: shut downs due to tcmax restriction 1985 0
0 0
0 0
1986 3
0 0
0 0
1987 0
0 0
0 0
1988 0
0 0
0 0
1991 0
0 0
0 0
1992 0
0 0
0 0
1993 54 0
0 0
0 1994 0
0 0
0 0
1995 0
0 0
0 0
1996 0
0 0
0 0
1997 0
0 0
0 0
1998 0
0 0
0 0
1999 26 0
0 0
0 2000 0
0 0
0 0
2001 0
0 0
0 0
2002 0
0 0
0 0
Total:
83 0
0 0
0
Table 3. Load Reductions and Tower Usage for Units 1, 2, and 3 at 120% Design Power Level with One New Rectangular Mechanical Draft Towers (Alternative 2)
Breakdown of Load Reductions and Tower Usage Number of Units: 3 Number of Towers: 6 Downstream Temperature Limit (24-hr avg): 90.0 Cooling Tower Capabilities: 80 80 96 96 80 80 Maximum Unit Reactor Power Levels (MWt): 3951 3951 3951 Maximum Unit Loads (MWe): 1280 1280 1280 Plant operation decisions based on 24 hr averaged downstream temperatures Maximum Unit Loads (MWe): 1280 1280 1280 Column 1: year Column 2: Net generation (MW-hr)
Column 3: Cumulative hours of reduced load Column 4: Cumulative hours of cooling tower usage Column 5: Total load reductions & tower energy (Mw-Hr)
Column 6: Total (non-tower) load reductions (Mw-Hr)
Column 7: Number of cooling-tower-hours of required operation Column 8: Load reductions due to 24-hr tdsmax restriction Column 9: Load reductions due to dtmmax restriction Column 10: Load reductions due to 1-hr tdsmax restriction Column 11: Load reductions due to bpmax restriction Column 12: Load reductions due to tcmax restriction 1985 33096688 0
234 7768 0
1050 0
0 0
0 0
1986 32652206 146 993 393411 355533 5145 355533 0
0 0
0 1987 33043236 0
713 26223 0
3544 0
0 0
0 0
1988 33159156 9
792 40738 10899 4020 10899 0
0 0
0 1991 33044952 0
723 27914 0
3777 0
0 0
0 0
1992 33257576 0
58 2025 0
269 0
0 0
0 0
1993 32747752 129 1063 332053 289749 5716 289749 0
0 0
0 1994 33126744 0
67 1788 0
236 0
0 0
0 0
1995 32926900 37 924 124301 87383 4983 87383 0
0 0
0 1996 33201432 0
283 9571 0
1289 0
0 0
0 0
1997 33128752 9
375 25914 10827 2034 10827 0
0 0
0 1998 33007588 0
773 29895 0
4048 0
0 0
0 0
1999 32904652 46 736 148832 119591 3946 119591 0
0 0
0 2000 33107752 10 817 43012 11404 4264 11404 0
0 0
0 2001 33088148 0
322 12627 0
1712 0
0 0
0 0
2002 32934980 21 1155 89804 43962 6194 43962 0
0 0
0 Tota:
5.28E+08 407 10028 1315876 929348 52227 929348 0
0 0
0
Table 4. Plant Shut Downs for Units 1, 2, and 3 at 120% Design Power Level with Two New Rectangular Mechanical Draft Towers in New Footprints (Alternative 2A)
Breakdown of Plant Shut Downs Number of Units: 3 Number of Towers: 6 Downstream Temperature Limit (24-hr avg): 90.0 Cooling Tower Capabilities: 80 80 96 96 80 80 Maximum Unit Reactor Power Levels (MWt): 3951 3951 3951 Maximum Unit Loads (MWe): 1280 1280 1280 Plant operation decisions based on 24 hr averaged downstream temperatures Column 1: year Column 2: shut downs due to 24-hr tdsmax restriction Column 3: shut downs due to dtmmax restriction Column 4: shut downs due to 1-hr tdsmax restriction Column 5: shut downs due to bpmax restriction Column 6: shut downs due to tcmax restriction 1985 0
0 0
0 0
1986 67 0
0 0
0 1987 0
0 0
0 0
1988 0
0 0
0 0
1991 0
0 0
0 0
1992 0
0 0
0 0
1993 48 0
0 0
0 1994 0
0 0
0 0
1995 18 0
0 0
0 1996 0
0 0
0 0
1997 0
0 0
0 0
1998 0
0 0
0 0
1999 26 0
0 0
0 2000 0
0 0
0 0
2001 0
0 0
0 0
2002 8
0 0
0 0
Total:
167 0
0 0
0
Table 5. Load Reductions And Tower Usage For Two Units At 105% Design Power Level With Existing Towers Breakdown of Load Reductions and Tower Usage Number of Units: 2 Number of Towers: 5 Downstream Temperature Limit (24-hr avg): 90.0 Cooling Tower Capabilities: 80 80 96 80 80 Maximum Unit Reactor Power Levels (MWt): 0 3457 3457 Maximum Unit Loads (MWe): 0 1152 1152 Plant operation decisions based on 24 hr averaged downstream temperatures Maximum Unit Loads (MWe): 0 1152 1152 Column 1: year Column 2: Net generation (MW-hr)
Column 3: Cumulative hours of reduced load Column 4: Cumulative hours of cooling tower usage Column 5: Total load reductions & tower energy (Mw-Hr)
Column 6: Total (non-tower) load reductions (Mw-Hr)
Column 7: Number of cooling-tower-hours of required operation Column 8: Load reductions due to 24-hr tdsmax restriction Column 9: Load reductions due to dtmmax restriction Column 10: Load reductions due to 1-hr tdsmax restriction Column 11: Load reductions due to bpmax restriction Column 12: Load reductions due to tcmax restriction 1985 19963872 0
94 2398 0
354 0
0 0
0 0
1986 19890914 18 664 46073 24606 3042 24606 0
0 0
0 1987 19932444 0
339 10391 0
1485 0
0 0
0 0
1988 20005356 0
490 14631 0
2100 0
0 0
0 0
1991 19933376 0
389 11647 0
1671 0
0 0
0 0
1992 20046560 0
0 0
0 0
0 0
0 0
0 1993 19810152 61 727 135282 111876 3319 111876 0
0 0
0 1994 19973198 0
9 172 0
27 0
0 0
0 0
1995 19915576 0
641 20977 0
2967 0
0 0
0 0
1996 20015942 0
105 2608 0
387 0
0 0
0 0
1997 19978358 0
242 7484 0
1068 0
0 0
0 0
1998 19922140 0
352 11091 0
1578 0
0 0
0 0
1999 19869140 27 498 75094 59274 2248 59274 0
0 0
0 2000 19984442 0
489 14461 0
2079 0
0 0
0 0
2001 19959420 0
146 4596 0
654 0
0 0
0 0
2002 19902668 0
738 22530 0
3222 0
0 0
0 0
Total:
3.19E+08 106 5923 379435 195756 26201 195756 0
0 0
0
Table 6. Plant Shut Downs For Two Units At 105% Design Power Level With Existing Towers Breakdown of Plant Shut Downs Number of Units: 2 Number of Towers: 5 Downstream Temperature Limit (24-hr avg): 90.0 Cooling Tower Capabilities: 80 80 96 80 80 Maximum Unit Reactor Power Levels (MWt): 0 3457 3457 Maximum Unit Loads (MWe): 0 1152 1152 Plant operation decisions based on 24 hr averaged downstream temperatures Column 1: year Column 2: shut downs due to 24-hr tdsmax restriction Column 3: shut downs due to dtmmax restriction Column 4: shut downs due to 1-hr tdsmax restriction Column 5: shut downs due to bpmax restriction Column 6: shut downs due to tcmax restriction 1985 0
0 0
0 0
1986 9
0 0
0 0
1987 0
0 0
0 0
1988 0
0 0
0 0
1991 0
0 0
0 0
1992 0
0 0
0 0
1993 40 0
0 0
0 1994 0
0 0
0 0
1995 0
0 0
0 0
1996 0
0 0
0 0
1997 0
0 0
0 0
1998 0
0 0
0 0
1999 27 0
0 0
0 2000 0
0 0
0 0
2001 0
0 0
0 0
2002 0
0 0
0 0
Total:
76 0
0 0
0
Table 7. Load Reductions And Tower Usage For Three Units At 100% Design Power Level With Original Towers Breakdown of Load Reductions and Tower Usage Number of Units: 3 Number of Towers: 6 Downstream Temperature Limit (24-hr avg): 90.0 Cooling Tower Capabilities: 80 80 80 80 80 80 Maximum Unit Reactor Power Levels (MWt): 3293 3293 3293 Maximum Unit Loads (MWe): 1098 1098 1098 Plant operation decisions based on 24 hr averaged downstream temperatures Maximum Unit Loads (MWe): 1098 1098 1098 Column 1: year Column 2: Net generation (MW-hr)
Column 3: Cumulative hours of reduced load Column 4: Cumulative hours of cooling tower usage Column 5: Total load reductions & tower energy (Mw-Hr)
Column 6: Total (non-tower) load reductions (Mw-Hr)
Column 7: Number of cooling-tower-hours of required operation Column 8: Load reductions due to 24-hr tdsmax restriction Column 9: Load reductions due to dtmmax restriction Column 10: Load reductions due to 1-hr tdsmax restriction Column 11: Load reductions due to bpmax restriction Column 12: Load reductions due to tcmax restriction 1985 28585390 0
148 4906 0
699 0
0 0
0 0
1986 28157826 189 820 390066 360057 4243 360057 0
0 0
0 1987 28525534 0
501 19124 0
2689 0
0 0
0 0
1988 28627942 0
633 25688 0
3598 0
0 0
0 0
1991 28519992 10 609 34348 9986 3416 9986 0
0 0
0 1992 28700332 0
18 344 0
54 0
0 0
0 0
1993 28193306 150 937 350834 313515 5230 313515 0
0 0
0 1994 28595610 0
38 1108 0
161 0
0 0
0 0
1995 28434696 38 846 110291 76601 4723 76601 0
0 0
0 1996 28648456 0
184 6485 0
920 0
0 0
0 0
1997 28563736 11 318 41704 29003 1783 29003 0
0 0
0 1998 28514820 0
572 21020 0
2973 0
0 0
0 0
1999 28408482 56 660 150105 124209 3636 124209 0
0 0
0 2000 28586760 20 657 44083 19494 3469 19494 0
0 0
0 2001 28571878 0
219 8547 0
1198 0
0 0
0 0
2002 28460740 22 993 65745 25976 5569 25976 0
0 0
0 Total:
4.56E+08 496 8153 1274398 958841 44361 958841 0
0 0
0
Table 8. Plant Shut Downs For Three Units At 100% Design Power Level With Original Towers Breakdown of Plant Shut Downs Number of Units: 3 Number of Towers: 6 Downstream Temperature Limit (24-hr avg): 90.0 Cooling Tower Capabilities: 80 80 80 80 80 80 Maximum Unit Reactor Power Levels (MWt): 3293 3293 3293 Maximum Unit Loads (MWe): 1098 1098 1098 Plant operation decisions based on 24 hr averaged downstream temperatures Column 1: year Column 2: shut downs due to 24-hr tdsmax restriction Column 3: shut downs due to dtmmax restriction Column 4: shut downs due to 1-hr tdsmax restriction Column 5: shut downs due to bpmax restriction Column 6: shut downs due to tcmax restriction 1985 0
0 0
0 0
1986 62 0
0 0
0 1987 0
0 0
0 0
1988 0
0 0
0 0
1991 0
0 0
0 0
1992 0
0 0
0 0
1993 62 0
0 0
0 1994 0
0 0
0 0
1995 18 0
0 0
0 1996 0
0 0
0 0
1997 8
0 0
0 0
1998 0
0 0
0 0
1999 26 0
0 0
0 2000 0
0 0
0 0
2001 0
0 0
0 0
2002 0
0 0
0 0
Total:
176 0
0 0
0