ML20150F162
| ML20150F162 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 05/22/1979 |
| From: | Burstein S WISCONSIN ELECTRIC POWER CO. |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| TASK-2.E.1.1, TASK-2.E.1.2, TASK-TM TAC-11692, TAC-11693, NUDOCS 7905310359 | |
| Download: ML20150F162 (8) | |
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Wisconsin Elecinc ece comvr 231 W. MICHIGAN, P o. 80X 2044, MILWAUl(EE, WI J3201 May 22, 1979 Mr A. Schwencer, Chief Operating Reactors Branch 1 U. S. NUCLEAR REGULATORY COMISSION Washington, D. C.
20555
Dear Mr. Schwencer:
? POINT BEACH NUCLEAR PLANT 00CKET NOS. 50-266 AND 50-301 RESPONSE TO TELECOPIED QUESTIONNAIRE This is in response to the questionnaire telecopied to us by your office on May 10,1979. A preliminary set of responses has already been telecopied to your office on an infortnal basis.
00ESTION I 1.
Pressurizer Heaters Balance of Plant Instrument Power Source - (class IE or non class IE or both) -
Backup Heater Power Source -
2.
Backup Heaters on set points =
off set points =
3.
Variable Heater Transfer.Functien -
4.
Spray Valve Transfer Function -
5.
Power Operated Relief Valve #2 (if applicable) open set point (in control output units) close set point (in control output units)
Describe Controller Transfer Function (output) -
psia including, Proportional Gain =
f Integral Gain =
7 906310 }N r'
Derivativo Gain =
'OR b$
SI:
Mro Ao Schwencer - Pr.ge Two May 22,1979 RESPONSE I 1.
Pressuri::er Heaters I
a.
Instrument Power Source: Safeguards battery powered inverter b.
Power Source for Proportional and Backup Heaters: The proportional heaters and te banks of backup heaters are on safeguard 480 volt buses which are powered by the diesel generators on loss of offsite power. Two banks of backup heaters are on non-safeguani buses which can be manually transferred to the diesel generators.
2.
Backup Heaters on set points = 2210 psig off set' points = 2220 psig 3.
Variable Heater Transfer Function: -3.33%/ psi (heating power per psi) 4 Spray Valve Transfer Function: 2%/ psi (spray valve lift per psi) 5.
In addition to the two spring operated relief valves which open at 2485 psig, there are two power (air) operated relief valves. Relief valve #1 receives a direct pressure signal, while relief valve #2 receives a compensated signal as described in item G.
The setpoints are as follows:
a.
Open set point - 2335 psig b.
Close set point - 2315 psig 6.
Pressurizer Pressure Controller Transfer Function: Supplies deviation signal to control the functions described above. Please refer to attached sketch on pressurizer pressuro control.
Proportional Gain: 4 Integral Gain:
Reset time: Unit 1 = 4 min; Unit'2 = 7 min Derivative Gain:
Not used 00ESTION II t
Describe all events that resultad in a complete loss of main feedwater over the last three years of operation.
Include as a minimum the following infonnation:
date, initiating event, power level, consequences (one paragraph description),
and safety significance of event.
Each event which occurred during a startup need not be described separately.
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RESP 0NSE II There has not been a loss of main feedwater in the last three years of operation.
Since the Plant became operational in 1970, there were three instances of loss of i
main feedwater.
In each of these events, auxiliary feedwater systems actuated pror;erly. These events did not pose a threat to the health and safety of the i
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public, as indicated below.
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i Mr. A. Schwencer - Page Three May 22,1979 l
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12-19-70: Unit 1 was operating at 35% power with one main feedwater purnp tagged out for maintenance. A loss of main feedwater occurred due to an apparent loss of suction pressure caused by a flooded suction low pressure switch on the remaining pump. Turbine trip automatically occurred and auxiliary feed started. One minute later, a reactor trip occurred due to low feed flow and feed flew / steam flow mismatch in one of the steam generators. All systems functioned properly.
2.
12-7-72: Unit 2 was operating at 20% power with one main feedwater pump tagged out for maintenance. A loss of main feeowater occurred due to an apparent loss of suction pressure caused by a frozen suction low pressure switch on the remaining pump. The turbine tripped normally, and auxiliary feed started.
In accordance with operating procedures, the reactor was brought to a hot, just critical condition until the suction pressure switch was thawed out. The unit was then brought back to power.
3.
10-13-73: A loss of off-site auxiliary power supplies occurred on Units 1 and 2.
This happened when a lightning mast fell upon and grounded the high side of the Unit 2 high voltage station auxiliary transfonners. The Unit I high voltage station auxiliary transformer was out of service for maintenance at the time and was receiving power from the Unit 2 buses.
Unit I was in a hot shutdown condition at the time and Unit 2 was at full power. Unit 1 experienced a loss of main feedwater. The shutdown rods tripped and auxiliary feed started. Unit 2 experienced a 20% runback as a result of the event but did not lose main feedwater and remained on line. Unit 2 auxiliaries supplied from the unit auxiliary transfonner did not lose power. The diesel generators started normally.
00ESTION III Provide a schematic diagram of the steam generator.
Identify important charac-teristics. As a minimum provide the liquid level and volume for nonnal plant operation at power and the liquid level and volume at low level set point for reactor trip (for W plants low level with steam flow / feed flow mismatch) subsequent to a loss of feedwater. Describe the bases for this determination including a description and use of steam generator level span.
RESPONSE tII 1.
See Figure 4.2-4 attached for diagram of steam generator.
2.
See Table 4.1-4 attached for list of steam generator characteristics.
3.
Liquid level at 100% power: 52% of 143 inch span
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Mr. A. Schwencer - Page Four May 22,1979 4.
The water volume at zero power is 2821 cubic feet. The water volume at 100% power is 1681 cubic feet.
If the assumption is made that all water in the steam generator secondary side is at saturated conditions of 521.20F and 821 psia, the water (liquid) mass is:
80,277 lbm = 1 0
09 ftJ/l bm 5.
The trip point for low level trip in conjunction with steam flow /feedwater flow mismatch is 20% of 143 inch span. The trip point for low-low level trip in either steam generator is set at about 10% of the 143 inch span, in accordance with the technical specification requirement that the set-point be t 5%.
6.
The secondary side liquid mass, per steam generator, at the 20% of indicated range low level setpoint is 59,800 lbn. This assumes 100%
power conditions. The source of this mass value is an infonnal transmittal of infci ation from Westinghouse.
Very truly yours, D
n
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MY Sol Burstein Exodut ye Vice President Attachments i
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TABLE 4.1-3 PRESSURIZER & PRESSURIZER RELIEF TANK DESIGN DATA Pressurizer Design / Operating Pressure, peig 2485/2235 Hydrostatic Test Pressure (cold), psig 3110 Design / Operating Temperature
'T 680/653 Water Volume Full Power, ft
- 600 Steam Volume, 7211 Power It 400 Surge Line Nossle Diameter, in./ Pipe Schedule 14/Sch 140 Shell ID,in./Kinimum Shell Thickness, in.
84/4.1 Minimum Clad Thickness, in.
0.188 P*
' Electric Heaters capacity, kw (total) 1000 Heatup rate of Pressurizar using Heaters only, 'F/hr 55 (Approximately)
Power Relief Valves
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Set Pressure (open), psig 2335 Capacity, Ib/hr Saturated steam / valve 179,000 Safety Valves Number 2
Set Pressure, psig 2485
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' Capacity, Ib/hr saturated sceam valve 288,000 Pr_assurizar Relief Tank Design pressure, peig 100 Rupture Disc Release Pressure, psig 100 Design temperature, 'F 340 Normal water temperature, *?
Containment Ambient 3
Total' volume, fc 800 Rupture Dise Relief Capacity, ib/hr 7.2 x 10
- 60% of not internal volume (eaximum calculated power)
,7 TABLE 4.1-4 i
s STEAM CENERATOR DESIGN DATA Number of Steam Generators 2
Design Pressure, Reactor Coolant / Steam, psig 2485/1085 Reactor Coolant Hydrostatic Test pressure (tube side-cold), peig 3110 Design Temperature, Reactor Coolant / Steam
- F 650/556 6
Reactor Coolant Flow, ib/hr 33.35 x 10 Total Heat Transfer Surfsce Area, f t 44,430 6
Heat Transferred, Reu/hr 2591 x 10 Steam Conditions at Full Load, Outlet Nossle 6
Steam Flow, Ib/hr 3.31 x 10 Ste'am Temperature. *F 521.2 Steam Pressure, psia 821' Feedwater Temperature. *F 436.6 overall Height, f t-in 63-1.6
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Shell CD, upper / lower, in.
166/127.5 Shell Thickness, upper / lower, in.
3.5/2.63 Number of U-tubes 3260 U-tube Diaester, in.
0.875 Tube Wall Thickness, (average), in.
0.050 Number of Manways/ID in 3/16
' Number of handholes/ID, in.
2/6 3
1 1518.5 MWe Zero Power Reactot Side Coolant Water Volume, it 928 928 6
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Primary Side Fluid Heat Content, Stu 24.99 x 10 24.42 x 10 l
Secondary Side Water Volume, it 1681 2821 3
,1 Secondary Side Stean Volume, it 2898 1758 6
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Secondary Side Fluid Heat Content, Stu 45.80 x 10 75.50 x 10 m.
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