ML20085K332
| ML20085K332 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 06/08/1995 |
| From: | Stang J NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20085K334 | List: |
| References | |
| NUDOCS 9506230293 | |
| Download: ML20085K332 (22) | |
Text
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UNITED STATES g
., j NUCLEAR REGULATORY COMMISSION o
e WASHINGTON, D.C. 305 6 0001
'44.....
COMMONWEALTH EDISON COMPANY DOCKET NO. 50-237 DRESDEN NUCLEAR POWER STATION. UNIT 2 AMENDMENT TO FACILITY OPERATING LICENSI Amendment No. 133 License No. DPR-19 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by the Commonwealth Edison Company (the licensee) dated October 15, 1992, as supplemented March 9, 1993, complies with the 1tandards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act and the rules and regulations of the Commission; C.
There is reasonable asseance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
Accordingly, the license is amended by changes to the Technical Specifi-cations as indicated in the attachment to this license amendment and pwagraph 2.C.(2) of Facility Operating License No. DPR-19 is hereby amended to read as follows:
1 i
P
..._ ~._.
i j
(2)
Technical Soecifications The Technical Specifications contained in Appendix A,- as revised through Amendment No.133,. are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.
3.
This license amendment is effective as of the d' te of its issuance and a
shall be implemented no later than December 31, 1995.
FOR THE NUCLEAR REGULATORY COMMISSION t
vY.
@voject DirecthnF.Stang,SekiorProjectMan P
te III-2 1
Division of Reactor Projects - III/IV j
Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications j
Date of Issuance: June 8, 1995 i
4
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p2 try
.p t
UNITED STATES j
NUCLEAR REGULATORY COMMISSION 3
Mg WASHINGTON, D.C. 20066-0001 p
%,...../
COMMONWEALTH EDISON COMPANY DOCKET NO. 50-249
((RESDEN NUCLEAR POWER STATION. UNIT 3 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 127 License No. DPR-25 j
1.
The Nuclear Regulatory Commission (the Commission) has found that:
j A.
The application for amendment by the Commonwealth Edison Company (the licensee) dated October 15, 1992, as supplemented March 9, 1993, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act and the rules and regulations of the Commission;
)
C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance witt, the Commission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
Accordingly, the license is amended by changes to the Technical Specifi-cations as indicated in the attachment to this license amendment and paragraph 3.B. of Facility Operating License No. DPR-25 is hereby amended to read as follows:
r
. B.
Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 127, are hereby incorporated in the-license. The licensee shall operate the facility in accordance with the Technical Specifications.
3.
This license amendment is effective as of the date of its issuance and shall be implemented no later than December 31, 1995.
{
FOR THE NUCLEAR REGULATORY COMMISSION l
ihn F. Stang, S Micr Project Manager Project Directorate III-2 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance:
June 8, 1995
i ATTACHMENT TO LICENSE AMENDMENT NOS.133 AND 127 FACILITY OPERATING LICENSE N05. DPR-19 AND DPR-25 DOCKET NOS. 50-237 AND 50-249 Revise the Appendix A Technical Specifications by removing the pages identified below and inserting the attached pages. The revised pages are identified by the captioned amendment number. The new inserted pages completely replace the removed pages.
REMOVE INSERT 1
3/4.4-1 3/4.4-1 3/4.4-2 3/4.4-2 3/4.4-3 3/4.4-3 3/4.4-4 3/4.4-4 3/4.4-5 B 3/4.4-6 B 3/4.4-1 B 3/4.4-7 B 3/4.4-2
STANDBY LIQUID CONTROL SYSTEM SLCS 3/4.4.A 3.4 - LIMITING CONDITIONS FOR OPERATION 4.4 - SURVEILLANCE REQUIREMENTS A.
Standby Liquid Control System (SLCS)
A.
Standby Liquid Control System The standby liquid control system (SLCS)
The standby Squid control system shall be shall be OPERABLE.
demonstrated OPERABLE:
1.
At least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> by verifying APPLICABILITY:
that:
OPERATIONAL MODE (s) 1,2, and 5"'.
a.
The temperature of the sodium pentaborate solution is greater than or equal to the limits of ACTION:
Figure 3.4.A-1.
j l
1.
In OPERATIONAL MODE 1 or 2:
b.
The volume of the sodium pentaborate solution is greater than a.
With one subsystem inoperable, or equal to the limits shown in restore the inoperable subsystem to Figure 3.4.A 2.
OPERABLE status within 7 days or be in at least HOT SHUTDOWN c.
The heat tracing circuit is within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
OPERABLE by determining the temperature of the pump suction j
b.
With both standby liquid control piping to be greater than or equa!
subsystems inoperable, restore at to 83*F.
least one subsystem to OPERABLE status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at 2.
At least once per 31 days by:
least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
a.
Verifying the continuity of the explosive charge.
2.
In OPERATIONAL MODE 5"':
b.
Determining" by chemical analysis that the available concentration of a.
With one subsystem inoperable, boron in solution is 14% by weight restore the inoperable subsystem to to 16.5% by weight.
OPERABLE status within 30 days or fully insert allinsertable control c.
Verifying that each valve, manual, rods within the next hour, power operated or automatic,in the flow path that is not locked, b.
With both standby liquid control sealed, or otherwise secured in subsystems inoperable, fully insert position, is in its correct position.
allinsertable control rods within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, With any control rod withdrawn. Not applicable to control rods removed per Specification 3.10.1 or 3.10.J.
a b
This surveillance shaft also be performed anytime water or boron is added to the solution or when the solution temperature drops below the hmits specified by Figure 3.4.A.1.
DRESDEN UNITS 2 & 3 3/4.4-1 Amendment Nos 133 and 127 j
1
\\
STANDBY LIQUID CONTROL SYSTEM SLCS 3/4.4.A i 3
1
' 3.4 - LIMITING CONDITIONS FOR OPERATION 4.4 - SURVEILLANCE REQUIREMENTS 3.
When tested pursuant to Specification -
4.0.E, by demonstrating that the I
minimum flow requirement of 40 gpm per pump at a pressure of greater than or equal to 1275 psig is met.
4.
At least once per 18 months by:
a.
Initiating one of the standby liquid '
control subsystems, including an explosive valve, and verifying that j
a flow path from the puraps to the reactor pressure vessel is available' by pumping domineralized water into the reactor vessel. The replacement charge for the explosive valve shall be from the same manufactured batch as the one fired or from another batch which has been certified by having one of that batch successfully fired. Both injection loops shall be tested in 36 months.
b.
Demonstrating that the pump relief valve setpoint is between 1455 and 1545 psig and verifying that the relief valve does not actuate during recirculation to the test tank at normal system pressures.
c.
Demonstrating that the pump suction line from the storage tank is not plugged by manually initiating the system, except the explosive valves, and pumping solution in the recirculation path.
\\
DRESDEN - UNITS 2 & 3 3/4.4-2 Amendment Nos 133 and 127
STANDBY LIQUID CONTROL SYSTEM SLCS 3/4.4.A FIGURE 3.4. A-1 SODIUM PENTABORATE SOLUTION TEMPERATURE REQUIREMENTS l
150
/
140 130 Acceptable Operating Region
,/
120 C110
/
e3 100 7
5
/
g 90
[
Ep 80 7
70
/
60
/
50
/
40 5
10 15 20 25 30 35 40 Sodium Pentaborate Concentration, % by Weight DRESDEN - UNITS 2 & 3 3/4.4-3 Amendment Nof 133 and 127
e STANDBY LfDUID CONTROL SYSTEM SLCS 3/4.4.A FIGURE 3.4. A.2 SODIUM PENTABORATE SOLUTION VOLUME REQUIREMENTS 5,600 g5,200 f
Acceptable Operating Region
]
e 4,800 m
Eo 4,4 0 0 --
>o
~N
'*<r= ter E
N o 4,000 -
O N
N'
'ro < r b 3,600
.E E
N r
N 3,200 -
A,,,,,
2 N....-
N N
2,800 14 14.5 15 15.5 16 16.5 Sodium Pentaborate Concentration, % by Weight DRESDEN - UNITS 2 & 3 3/4.4-4 Amendment No s 133 and 127
SLCS B 3/4.4 BASES 3/4.4.A STANDBY LIQUID CONTROL SYSTEM The standby liquid control system consists of an unpressurized tank for low temperature sodium pentaborate solution storage, a pair of full capacity positive displacement pumps, two explosive actuated shear plug valves, the poison sparger ring, and the necessary piping, valves and instrumentation. An OPERABLE standby liquid control system provides backup capability for reactivity control independent of normal reactivity control provisions provided by the control rods.
OPERABILITY of the system is based on the conditions of the borated solution in the storage tank and the availability of a flow path to the reactor pressure vessel, including the pumps and valves.
Two subsystems are required to be OPERABLE: each contains a pump, an explosive valve, and the associated piping, valves, and necessary instruments and controls to ensure an OPERABLE flow path. Inoperability of a nonredundant component, such as the tank, affects both subsystems.
The standby liquid control system provides the capability for bringing the reactor from full power to a cold, xenon-free shutdown assuming that none of the withdrawn control rods can be inserted.
To meet this objective,it is designed to inject a quantity of boron which produces a concentration of no less than 600 ppm of boron in the reactor core in less than 100 minutes. This boron concentration is required to bring the reactor from full power to a 3% Ak/k or more subcritical condition, considering the hot to cold reactivity swing and xenon poisoning. An additional margin of 25% boron is provide to compensate for possible losses and imperfect mixing of the chemical solution in the reactor water. This results in an average concentration of 750 ppm of boron in the reactor core assuming no losses. A net quantity of 3035 gallons of solution at less than or equal to 1100F and having a 14 weight percent sodium pentaborate (NA B oO 10H O) concentration 2 3 3
2 is required to meet this shutdown requirement. An additional volume of solution is contained below the pump suction and is not available for injection. Other equivalent combinations of increased concentration and reduced volume are also acceptable provided they have considered required temperatures and net positive suction head.
The specified pumping rate of 40 gpm will meet the above design objective. This insertion rate of boron solution will override the rate of reactivity insertion due to cooldown of the reactor following the xenon peak. Two pump operation will enable faster reactor shutdown for anticipated transients without scram (ATWS) events. The required minimum flow combined with the solution concentration requirements are sufficient to comply with the requirements of 10 CFR 50.62.
With redundant pumps and explosive injection valves and with a highly reliable control rod scram system, operation of the reactor is permitted to continue for short periods of time with the system inoperable or for longer periods of time with one of the subsystems inoperable.
Surveillance requirements are established on a frequency that assures a high reliability of the system. The standby liquid control system is operated by a five position control switch which allows single pump operation for surveillance testing. This testing demonstrates the capability of firing the explosive trigger assemblies, and injects clean demineralized water from the test tank to the reactor vessel to demonstrate the injection line is not plugged. Locally controlled testing circulates sodium pentaborate from the storage tank, through one suction line, through a pump,
)
and back into the storage tank. This is done separately for each system to demonstrate that both DRESDEN - UNITS 2 & 3 8 3/4.4 1 Amendment Nos 133 and 127
SLCS B 3/4.4 BASES suction lines are not plugged. The only practical time to test the standby liquid control system is during a refueling outage. Components of the system are checked periodically and make a more frequent functional test of the entire system unnecessary, A test of explosive charges from one manufacturing batch is made to assure that the charges are satisfactory. A continual check of the firing circuit continuity is provided by pilot lights in the control room.
The two pump operation switch positions will be used for the injection of the sodium pentaborate into the vessel during an ATWS event. By using the two pump operation position, the standby liquid control system will comply with the requirements of 10 CFR 50.62. Comparison of the initial two-pump test data with initial single-pump test data has verified the capability of the piping to support two-pump flow. Periodic single-pump test data is compared to the required flow rate and to the previous test data to identify any significant degradation.
A 10 F margin is included in Figure 3.4.A-1 above saturation temperature to guard against boron precipitation. Temperature and liquid level alarms for the system are annunciated in the control room. Once the solution has been made up, boron concentration will not vary significantly unless more boron or more water is added. Tank levelindication and alarms are provided to indicate whether the solution volume has changed, which might indicate a possible solution concentration change.
Figure 3.4.A 2 provides additional requirements for minimum solution volume, based on existing solution temperature and concentration, to ensure adequate net positive suction head exists for two pump operation it is permissible to interpolate between the temperature curves.
DRESDEN - UNITS 2 & 3 8 3/4.4-2 Amendment Nos 133 and 127
P o * %
E*~[E UNITED STATES Q;v, NUCLEAR REGULATORY COMMISSION f
wAssiwof ON, D.C. 20555-0001 g-j COMMONWEALTH EDISON COMPANY AND IOWA-ILLIN0IS GAS AND ELECTRIC COMPANY DOCKET NO. 50-254 OVAD CITIES NUCLEAR POWER STATION. UNIT 1 A!fNDMENT TO FACILITY OPERATING LICENSE Amendment No. 154 License No. DPR-29 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Commonwealth Edison Company (the licensee) dated October 15, 1992, as supplemented March 9, 1993, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act) and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 3.B. of Facility Operating License No. DPR-29 is hereby amended to read as follows:
3 a
B.
Technical Soecifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 154, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.
3.
This license amendment is effective as of the date of its issuance and shall be implemented no later than June 30, 1996.
FOR THE NUCLEAR REGULATORY COMMISSION te Robert M. Pulsifer, Project Manager Project Directorate III-2 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance:
June 8. 1995
\\
3
- g. e UNITED STATES.
.j lj NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 3066H001
%, *....f COMONWEALTH EDISON COMPANY T
IOWA-ILLIN0IS GAS AND ELECTRIC COMPANY r
DOCKET NO. 50-265 OVAD CITIES NUCLEAR POWER STATION. UNIT 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 150 License No. DPR-30 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Commonwealth Edison Company (the licensee) dated October 15, 1992, as supplemented March 9, 1993, i
complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act) and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the appli_o* ion, the provisions of the Act, and the rules and regulations N the i
Commission; C.
There is reasonable assurance (1) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; 1
l D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 3.B. of Facility Operating License No. DPR-30 is hereby amended to read as follows:
}
c
... B.
Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No.150, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.
3.
This license amendment is effective as of the date if its issuance and shall be implemented no later than June 30, 1996.
FOR THE NUCLEAR REGULATORY COMMISSION r
Robert M. Pulsi er, Project Manager Project Directorate III-2 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance:
June 8, 1995
e ATTACHMENT TO LICENSE AMENDMENT NOS. 154 AND 150 FACILITY OPERATING LICENSE NOS. DPR-29 AND DPR-30 DOCKET NOS. 50-254 AND 50-265 Revise the Appendix A Technical Specifications by removing the pages identified below and inserting the attached pages. The revised pages are identified by the captioned amendment number.
The new inserted pages completely replace the removed pages.
REMOVE INSERT 3/4.4-1 3/4.4-1 3/4.4-2 3/4.4-2 3/4.4-3 3/4.4-3 3/4.4-4 3/4.4-4
- 3/4.4-5 B 3/4.4-1 B 3/4.4-2 Figure 3.4-1 Figure 3.4-2 l
1 Quad Cities Unit 1 only
=
~
STANDBY LIQUID CONTROL SYST.fM SLCS 3/4.4.A e
i 3.4 - LIMITING CONDITIONS FOR OPERATION 4.4 - SURVEILLANCE REQUIREMENTS A.
Standby Liquid Control System (SLCS)
A.
Standby Liquid Control System The standby liquid control system (SLCS)
The standby liquid control system shall be shall be OPERABLE.
demonstrated OPERABLE:
I 1.
At least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> by verifying APPLICABILITY:
that:
OPERATIONAL MODE (s) 1,2, and 5'*1 a.
The temperature of the sodium pentaborate solution is greater than or equal to the limits of ACTION:
Figure 3.4.A-1.
1.
In OPERATIONAL MODE 1 or 2:
b.
The volume of the sodium pentaborate solution is greater than a.
With one subsystem inoperable, or equal to the limits shown in restore the inoperable subsystem to Figure 3.4.A-2.
OPERABLE status within 7 days or be in at least HOT SHUTDOWN c.
The heat tracing circuit is within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
OPERABLE by determining the temperature of the pump suction b.
With both standby liquid control piping to be greater than or equal subsystems inoperable, restore at to 83'F.
j least one subsystem to OPERABLE status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at 2.
At least once per 31 days by:
least HOT SHUTDOWN within the i
next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
a.
Verifying the continuity of the explosive charge.
2.
In OPERATIONAL MODE SN:
b.
Determining
- by chemical analysis that the available concentration of a.
With one subsystem inoperable, boron in solution is 14% by weight restore the inoperable subsystem to to 16.5% by weight.
OPERABLE status within 30 days or fully insert allinsertable control c.
Verifying that each valve, manual, rods within the next hour.
power operated or automatic,in the flow path that is not locked, b.
With both standby liquid control sealed, or otherwise secured in subsystems inoperable, fully insert position, is in its correct position, all insertable control rods within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
a With any control rod withdrawn. Not applicable to control rods removed per Specification 3.10.1 or 3.10.J.
b This surveillance shat! also be performed anytime water or boron is added to the solution or when the solution temperature drops below the limits specified by Figure 3.4.A 1.
QUAD CITIES - UNITS 1 & 2 3/4.4 1 Amendment Nos 154 and 150 a
m-
~
r 9
STANDBY LIQUID CONTROL SYSTEM SLCS 3/4.4.A 3.4 - LIMITING CONDITIONS FOR OPERATION 4.4 - SURVEILLANCE REQUIREMENTS 3.
When tested pursuant to Specification 4.0.E, by demonstrating that the minimum flow requirement of 40 gpm per pump at a pressure of greater than or soual to 1275 psig is met.
4.
At least once per 18 months by:
a.
Initiating one of the standby liquid control subsystems, including an explosive valve, and verifying that a flow path from the pumps to the reactor pressure vesselis available by pumping domineralized water into the reactor vessel. The replacement charge for the explosive valve shall be from the same manufactured batch as the 1
one fired or from another batch i
which has been certified by having one of that batch successfully fired. Both injection loops shall be tested in 3E months.
b.
Demonstrating that the pump relief valve etpo nt is between 1455.
and 1545 rsig and verifying that the relief valve does not actuate during recirculation to the test tank at normal system pressures, c.
Demonstrating that the pump suction line from the storage tank is not plugged by manually initiating the system, except the explosive valves, and pumping solution in the recirculation path.
OUAD CITIES - UNITS 1 & 2 3/4.4-2 Amendment Nos 154 and 150
5 STANDBY LIQUID CONTROL SYSTEM SLCS 3/4.4.A FIGURE 3.4.A 1 SODIUM PENTABORATE SOLUTION TEMPERATURE REQUIREMENTS i
150
/
140 130-Acceptable Operating Region
,/
120 C110
/
e3 100 g
5
}
g 90
[
Ep 80 7
70
/
60
/
50-40,
5 10 15 20 25 30 35 40 Sodium Pentaborate Concentration, % by Weight OUAD CITIES - UNITS 1 & 2 3/4.4-3 Amendment Nos 154 and 150 h.-
+
-mr ur-iev
^
-e
STANDBY LIQUID CONTROL SYSTEM e-SLCS 3/4.4.A FIGURE 3.4.A-2 SODIUM PENTABORATE SOLUTION VOLUME REQUIREMENTS i-5,600 5
9,200
[o Acceptable Operating Region h4,800 1
N 2 4,400 -
N* < r.
>o N
N a
N 8 4,000 -%
oo,7 y
wr E
N
@ 3'600 -'N r,,,,
N
.s2 3,200 -
A N
2,800 14 14.5 15 15.5 16 16.5.
Sodium Pentaborate Concentration, % by Weight OUAD CITIES - UNITS 1 & 2 3/4.44 Amendment Nos 154 and 150
SLCS B 3/4.4 BASES 3/4.4.A STANDSY LIQUID CONTROL SYSTEM The standby liquid control system consists of an unpressurized tank for low temperature sodium pentaborate solution storage, a pair of full capacity positive displacement pumps, two explosive actuated shear plug valves, the poison sparger ring, and the necessary piping, valves and instrumentation. An OPERABLE standby liquid control system provides backup capability for reactivity control independent of normal reactivity control provisions provided by the control rods.
OPERABILITY of the system is based on the conditions of the borated solution in the storage tank and the availability of a flow path to the reactor pressure vessel, including the pumps and valves.
Two subsystems are required to be OPERABLE: each contains a pump, an explosive valve, and the associated piping, valves, and necessary instruments and controls to ensure an OPERABLE flow path, inoperability of a nonredundant component, such as the tank, affects both subsystems.
The standby liquid control system provides the capability for bringing the reactor from full power to a cold, xenon free shutdown assuming that none of the withdrawn control rods can be inserted.
To meet this objective, it is designed to inject a quantity of boron which produces a concentration of no less than 600 ppm of boron in the reactor core in less than 100 minutes. This boron concentration is required to bring the reactor from full power to a 3% Ak/k or more suberitical condition, considering the hot to cold reactivity swing and xenon poisoning. An additional margin of 25% boron is provide to compensate for possible losses and imperfect mixing of the chemical solution in the reactor water. This results in an average concentration of 750 ppm of boron in the reactor core assuming no losses. A not quantity of 3254 gallons of solution at less than or equal to 110'F and having a 14 weight percent sodium pentaborate (NA B ioO 10H O) concentration 2
i 2
is required to meet this shutdown requirement. An additional volume of solution is contained below the pump suction and is not available for injection. Other equivalent combinations of increased concentration and reduced volume are also acceptable provided they have considered required temperatures and net positive suction head.
The specified pumping rate of 40 gpm will meet the above design objective. This insertion rate of boron solution will override the rate of reactivity insertion due to cooldown of the reactor following the xenon peak. Two pump operation will enable faster reactor shutdown for anticipated transients without scram (ATWS) events. The required minimum flow combined with the solution concentration requirements are sufficient to comply with the requirements of 10 CFR 50.62.
With redundant pumps and explosive injection valves and with a highly reliable control rod scram system, operation of the reactor is permitted to continue for short periods of time with the system inoperable or for longer periods of time with one of the subsystems inoperable.
Surveillance requirements are established on a frequency that assures a high reliability of the system. The standby liquid control system is operated by a five position control switch which allows single pump operation for surveillance testing. This testing demonstrates the capability of firing the explosive trigger assemblies, and injects clean domineralized water from the test tank to the reactor vessel to demonstrate the injection line is not plugged. Locally controlled testing circulates sodium pentaborate from the storage tank, through one suction line, through a pump, and back into the storage tank. This is done separately for each system to demonstrate that both OUAD CITIES - UNITS 1 & 2 B 3/4.4 1 Amendment No s 154 and 150
l St.CS B 3/4.4 BASES suction lines are not plugged. The only practical time to test the standby liquid control system is during a refueling outage. Components of the system are checked periodically and make a more frequent functional test of the entire system unnecessary. A test of explosive charges from one manufacturing batch is made to assure that the charges are satisfactory. A continual check of the 1
firing circuit continuity is provided by pilot lights in the control room.
The two pump operation switch positions will be used for the injection of the sodium pentaborate into the vessel during an ATWS event. By using the two pump operation position, the standby i
liquid control system will comply with the requirements of 10 CFR 50.62. Comparison of the
{
initial two-pump test data with initial single pump test data has verified the capability of the piping to support two-pump flow. Periodic single-pump test data is compared to the required flow rate and to the previous test data to identify any significant degradation.
A 10'F margin is included in Figure 3.4.A-1 above saturation temperature to guard against boron precipitation. Temperature and liquid level alarms for the system are annunciated in the control room. Once the solution has been made up, boron concentration will not vary significantly unless more boron or more water is added. Tank levelindication and alarms are provided to indicate whether the solution volume has changed, which might indicate a possible solution concentration change.
Figure 3.4.A 2 provides additional requirements for minimum solution volume, based on existing solution temperature and concentration, to ensure adequate net positive suction head exists for two pump operation. It is permissible to interpolate between the temperature curves.
QUAD CITIES - UNITS 1 & 2 B 3/4.4 2 Amendment Nos 154 and 150