ML20235G839
| ML20235G839 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 09/22/1987 |
| From: | GEORGIA POWER CO. |
| To: | |
| Shared Package | |
| ML20235G836 | List: |
| References | |
| TAC-66471, NUDOCS 8709300252 | |
| Download: ML20235G839 (7) | |
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l REACTIVITY CON?ROL SYSTEMS
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3 /4.1. 5 STANDBY L1001D CONTRO S'YSTEM LIMITING CONDITION FOR OFERATION 3.1.5 The standby liquid control system shall be OPERABLE with:
a.
An OPERABLE flow path from the storage tank to the reactor core containing two pumps and two inline explosive injection valves, and b.
The contained solution volume, concentration and temperature are within the Operating Ranges of Figure 3.1.5-1 and Figure 3.1.5-2.
APPLICABILITY: CONDITIONS 1, 2, and 5*.
ACTION:
a.
In CONDITION 1 or 2:
1.
With one pump and/or one explosive valve inoperable, restore the inoperable pump and/or explosive valve to OPERABLE status within 7 days or be in at least HG1 SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
2.
With the standby liquid control system inoperable, restore the system 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 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 />, b.
In CONDITION 5*:
1.
With one pump and/or one explosive valve inoperable, restore the inoperable pump and/or explosive valve to OPERABLE status within 30 days or fully insert all insertable control rods within the next hour.
2.
With the standby liquid control system inoperable, fully insert all insertable" control rods within one hour.
Theprovision[ofSpecification3.0.3and3.0.4arenot 3.
applicable.
- With any control rod withdrawn. Not applicable to control rods removed per Specification 3.9.11.1 or 3.9.11.2.
HATCH - UNIT 2 3/4 1-18 Proposed TS/00954/
P
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REACTIVITY CONTROL SYSTEMS i
SURVEILLANCE RE0VIREMENTS 4.1.5 The standby liquid control system shall be demonstrated OPERABLE:
a.
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 that:
1.
The temperature of the sodium pentaborate solution is.
within the limits of Figure 3.1.5-2, and l
2.
The volume of sodium pentaborate solution is within the limits of Figure 3.1.5-1, and 3.
The heat tracing circuit is OPERABLE by determining that the temperature of the pump suction piping is within the limiu of Figure 3.1.5-2.
b.
At least once per 31 days by:
1.
Starting each pump and recirculating dem.neralized water i
to the test tank, 2.
Verifying the continuity of the explosive charge, and 3.
Determining that the concentration of boron in solution l
is within the limits of Figure 3.1.5-1 by chemical analysis.*
c.
At least once per 18 months during shutdown by; 1.
Initiating one of the standby liquid control system loops, including an explosive valve, and verifying that a flow path from the pumps to the reactor pressure vessel is available by pumping demineralized 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 certifieri by having one of that batch successfully fired.
Both injection test loops shall be tested in 36 months.
2.
Demonstrating that the minimum flow requirement of 41.2 gpm at a pressure of 1190 psig is met.
3.
Demonstrating that the pump relief valve setpoint < 1400 psig and verifying that the relief valve does not actuate during recirculation to the test tank.
4.
- Demonstrating that all heat traced piping is unblocked by pumping from the storage tank to the test tank.
5.
Prior to startup, verify (by analysis) that the sodium pentaborate enrichment is within prescribed limits.
- This test shall also be performed anytime water or boron is added to the solution or when the solution temperature drops below the lower limit established in Figure 3.1.5-2.
l
- This test shall also be performed whenever both heat tracing circuits have been found to be inoperable.
HATCH - UNIT 2 3/4 1-19 Proposed TS/00954/
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FIGURE 3.1.51 SODIUM PENTABORATE SOLUTION VOLUME VERSUS CONCENTRATION REQUIREMENTS HATCH-UNIT 2 3/4 1/20 Proposed TS/0101q/364
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FIGURE 3.1.5-2 SODIUM PENTABORATE SOLUTION TEMPERATURE VERSUS CONCENTRATION REQUIREMENTS i
HATCH-UNIT 2 3/4 1/20a Proposed TS/0101q/364
REACTIVITY CONTROL SYSTEMS BASES CONTROL R005 PROGRAM CONTROLS (Continued)
The RSCS and RWM provide automatic supervision to assure that out-of-sequence rods will not be withdrawn or inserted.
The analysis of the rod drop accident is presented in Section 15.1.38 of the FSAR and the techniques of the analysis are presented in a topical report, Reference 1, and two supplements, References 2 and 3.
The RBM is designed to automatically prevent fuel damage in the event of erroneous rod withdrawal from locations of high power density during high power operation.
The RBM is only required to be operable when the Limiting Condition defined in Specification 3.1.4.3 exists.
Two channels are provided.
Tripping one of the channels will block erroneous rod with-drawal soon enough to prevent fuel damage.
This system backs up the written sequence used by the operator for withdrawal of control rods.
Further dis-cussion of the RBM system and power dependent setpoints may be found in NEDC-30474-P (Ref 4).
3/4.1.5 STANDBY LIQUID CONTROL SYSTEM The standby liquid control (SLC) system provides a backup reactivity control capability to the control rod scram system.
The original design basis for the standby liquid control system is to provide a soluble boron concentration to the reactor vessel sufficient to bring the reactor to a cold shutdown.
In addition to meeting its original design basis, the system must also satisfy the requirements of the ATWS Rule 10 CFR 50.62 paragraph (c) (4),
which requires that the system have a control capacity equivalent to that for a system with an injection rate of 86 gpm of 13 weight percent unenriched sodium pentaborate, normalized to a 251 inch diameter reactor vessel.
To meet its original design basis, the SLC system was designed with a sodium pentaborate solution tank, redundant pumps, and redundant explosive injection valves.
The tank contains a sodium pentaborate solution of suf ficient volume, concentration and B2' enrichment to bring the reactor to a cold shutdown. The solution is injected into the reactor vessel using one of the redundant pumps.
The volume limits in Figure 3.1.5-1 are calculated such that for a given concentration of sodium pentaborate, the tank contains a volume of solution adequate to bring the reactor to a cold shutdown, with margin.
These volume limits are based on gross volume and account for the unusable volume of solution in the tank and suction lines.
To meet 10 CFR 50.62 Paragraph (c) (4), the system must have a reactivity control capacity equivalent to that of a system with an 86 gpm injection flow rate of 13 weight percent unenriched sodium pentaborate into a 251 inch diameter reactor vessel.
The term " equivalent reactivity control capacity" refers to the rate at which t e boron isotope B2' is injected into the reactor core.
The standby liquid control system meets this requirement HATCH - UNIT 2 B 3/4 1-4 Proposed TS/0097q/
I
'+.
REACTIVITY CONTROL SYSTEMS BASES STANDBY LIQUID CONTROL SYSTEM (Continued) by using a sodium pentaborate solution enriched with a higher concentration of the B2' isotope.
The minimum concentration limit of 6.2 percent sodium pentaborate solution is based on 60 atomic percent B" enriched boron in sodium pentaborate and a flow rate of 41.2 gpm.
The method used to show equivalence with 10 CFR 50.62 is set forth in NEDE-31096-P (Ref. 5).
Limiting Conditions for Operation are established based on the redundancy within the system and the reliability of the control rod scram system. With the standby liquid control system inoperable, reactor operation for short periods of time is justified because of the reliability of the control rod scram system. With one redundant component inoperable, reactor operation for longer periods of time is jus' fied because the system could still fulfill its function.
Surveillance requirements are established on a frequency that assures a high system reliability.
Thorough testing of the system each operating cycle assures that the system can be actuated from the control room and will develop the flow rate required.
Replacement of the explosive charges in the valves at regular intervals assures that these valves will not fail due to deterioration of the charges.
Functional testing of the pumps is performed once per month to assure pump operability.
The sodium pentaborate solution is carefully monitored to assure its reactivity control capability is maintained.
The enriched sodium pentaborate solution is made by mixing granular, enriched sodium pentaborate with water.
Isotopic tests on the granular sodium pentaborate are performed to verify the actual B" enrichment, prior to mixing with water.
Once the enrichment is established, only the solution concentration, volume and temperature must be monitored to insure that an adequate amount of reactivity control is available.
Determining the solution concentration once per 31 days verifies that the solution has not been diluted with water.
Checking the volume once each day will guard against noticeable fluid losses or dilutions, and daily temperature checks will prevent sodium pentaborate precipitation.
1.
C. J. Paone, R. C. Stirn and J. A. Woodley, " Rod Drop Accident Analysis for Large BWRs," GE Topical Report NEDO-10527, March 1972.
2.
C. J. Paone, R. C. Stirn and R. M. Yound, Supplement 1 to NED0-10527, July 1972.
)
3.
J. A. Haum, C. J. Paone and R. C. Stirn, Addendum 2, " Exposed Cores,"
Supplement 2 to NED0-10527, January 1973.
i l
i HATCH - UNIT 2 B 3/4 1-4a Proposed TS/0097q/
j I
REACTIVITY CONTROL SYSTEMS BASES STANDBY LIQUID CONTROL SYSTEM (Continued) 4.
" Average Power Range Monitor, Rod Block Monitor and Technical Specifi-cation Improvement (ARTS) Program for Edwin I. Hatch Nuclear Plant, Units I and 2," NEDC-30474-P, December 1983.
G.
" Anticipated Transients without Scram, Response to NRC ATWS Rule, 10 CFR 50.62", NEDE-31096-P, December 1985.
HATCH - UNIT 2 B 3/4 1-4b Proposed TS/0097q/