ML20137G490
| ML20137G490 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 03/27/1997 |
| From: | ENTERGY OPERATIONS, INC. |
| To: | |
| Shared Package | |
| ML20137G477 | List: |
| References | |
| NUDOCS 9704010405 | |
| Download: ML20137G490 (6) | |
Text
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EMERGENCY CORE COOLING SYSTEMS j
SURVEILLANCE RE0dIREMENTS 4.5.2 Each ECCS subsystem shall be demonstrated OPERABLE:
a.
At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying that the following valves j
are in the indicated positions with the valves key-locked shut:
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Valve Number Valve Function Valve Position i
j a.
2SI-V1556 a.
Hot Leg Injection a.
SHUT l
(SI-506A) l b.
2SI-V1557 b.
Hot Leg Injection b.
SHUT
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(SI-502A) l c.
2SI-V1558 c.
Hot Leg Injection c.
SHUT i
(SI-5028) d.
2SI-V1559 d.
Hot Leg Injection d.
SHUT (SI-5068) i b.
At least once per 31 days by verifying that each valve (manual, I
power-operated, or automatic) in thd~ flow path that is not locked, l
sealed, or otherwise secured in position, is in its correct position.
c.
By a visual inspection which verifies.that no loose debris (rags, j
trash, clothing, etc.) is present in the containment which could be 1
transported to the safety injection system sump and cause restriction i
cf the pump suctions during LOCA conditions.
This visual inspection i
shall be performed:
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1.
For all accessible areas of the containment prior to establishing CONTAIMENT INTEGRITY, and 2.
Of the areas affected within containment at the completion of containment entry when CONTAIMENT INTEGRITY is established.
1 d.
At least once per 18 months by:
1.
Verifying the action of the open permissive interlock (0PI) and isolation valve position alams of the shutdown cooling system when the reactor coolant system pressure (actual or simulated) is between 392 psia sad 422 psia.
WATERFORD - UNIT 3 3/4 5-4 AMENDMENT N0. 65
EMERGENCY CORE COOLING SYSTEMS BASES ECCS SUBSYSTEMS (Continued)
With the RCS temperature below 350*F, one OPERABLE'ECCS subsystem.is acceptable without single failure consideration on the basis of the stable i
reactivity condition of the reactor and the limited core cooling requirements.
The trisodium phosphate dodecahydrate (TSP) stored in dissolving baskets.
located in the containment basement is provided to minimize the possibility of corrosion cracking of certain metal components during operation of the ECCS following a LOCA.
The TSP provides this protection by dissolving in the sump water and causing its final pH to be raised to greater than or equal to 7.0.
The Surveillance Requirements provided to' ensure OPERABILITY of each component ensure that at a minimum, the assumptinns used in the safety-analyses are met and that subsystem OPERABILITY is maintained.
Surveillance Requirements for throttle valve position stops and flow balance testing pro-vide assurance that proper ECCS flows will be maintained in the event of a i
LOCA. Maintenance of proper flow resistance and pressure drop in the piping system to each injection point is necessary to:
(1) prevent total pump flow 1
from exceeding runout conditions when the system is in its m'inimum resistance configuration, (2) provide the proper flow split between injection points in
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-accordance with the assumptions used in the ECCS-LOCA analyses, and (3) provide an acceptable level of total ECCS flow to all injection points equal to or above that assumed in the ECCS-LOCA analyses..The requirement to dissolve a representative sample of TSP in a sample of water borated within RWSP boron-concentration limits provides assurance that the stored TSP will dissolve in borated water at the postulated post-LOCA temperatures.
The requirement to verify the minimum pump discharge pressure on recircula-tion flow ensures that the pump performance curve has not degraded below that used to show that the pump exceeds the design flow condition assumed in the i
safety analysis and is consistent with the requirements of ASME Section XI.
3/4.5.4 REFUELING WATER STORAGE POOL (RWSP)
-The OPERABILITY of the refueling water storage pool (RWSP) as part of the ECCS also ensures that a sufficient supply of borated water is available for injection by the ECCS in the' event of a-LOCA.
The limits on RWSP minimum volume and boron concentration ensure that (1) sufficient water is available within. containment to permit recirculation cooling flow to the core, and (2) the reactor will remain subcritical in the cold condition following mixing of the RWSP and the RCS water volumes with all CEAs inserted ex ept for the most reactive control assembly. These assumptions are consistent with the LOCA analyses.
1 WATERFORD - UNIT 3 8 3/4 5-2 l
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1 NPF-38-192 i
ATTACHMENT B l
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.-e,
4 EMERGENCY CORE COOLING SYSTEMS i
SURVEILLANCE REQUIREMENTS 4.5.2 Each ECCS subsystem shall be demonstrated OPERABLE:
i
}:
- a. At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying that the following valves are in the indicated j
positions with the valves key-locked shut:
l Valve Number Valve Function Valve Position i
- a. 2SI-V1556
- a. Hot Leg injection
- a. SHUT l
(SI-506A)
- b. 2SI-V1557
~ b. Hot Leg injection
- b. SHUT (SI-502A) l
- c. 2SI-V1558
- c. Hot Leg injection
- c. SHUT i
(Q-5028)
- d. 2SI-V1559
- d. Hot Leg Injection
- d. SHUT (SI-506B)
- b. At least once per 31 days by:
- 1. Verifying that each valve (manual, power-operated, or automat lc) in the flow path that is not locked, sealed, or otherwise secured in position, is in its correct position.
- 2. Verifying the ECCS piping is full of water,
- c. By a visual inspection which verifies that no loose debris (rags, trash, clothing, etc.) is present in the containment which could be transported to the safety injection system sump and cause restriction of the pump suctions during LOCA conditions. This visual inspection shall be performed:
- 1. For all accessible areas of the containment prior to establishing CONTAINMENT INTEGRITY, and
- 2. Of the areas affected within containment at the completion of containment entry when CONTAINMENT INTEGRITY is established.
- d. At least once per 18 months by:
- 1. Verifying the action of the open permissive interlock (OPI)and isolation valve position alarms of the shutdown cooling system when the reactor coolant system pressure (actual or simulated) is between 392 psia and 422 psia.
WATERFORD - UNIT 3 3/4 5-4 AMENDMENT NO. 65
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EMERGENCY CORE COOLING SYSTEMS j
i BASES i
ECCS SUBSYSTEMS (Continued)
With the RCS temperature below 350 F, one OPERABLE ECCS subsystem is-i acceptable without single failure consideration on the basis of the stable reactivity l
condition of the reactor and the limited core cooling requirements.
i The trisodium phosphate dodecahydrate (TSP) stored in dissolving baskets located in the containment basement is provided to minimize the possibility of corrosion
{
cracking of certain metal components during operation of the ECCS following a LOCA.
The TSP provides this protection by dissolving in the sump water and causing its final pH to be raised to greater than or equal to 7.0, With the exception of systems in operation, the ECCS pumps are normally in a
)
standby, nonoperating mode. As such, flow path piping has the potential to develop voids and pockets of entrained gases. Maintaining the piping from the ECCS pumps to 1
l the RCS full of water ensures that the system will perform properly, injecting its full
)
capacity into the RCS upon demand. This will prevent water hammer, pump cavitation, j
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and pumping noncondensible gas (e.g., sir, nitrogen, or hydrogen) into the reactor
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vessel following an SlAS or during SDC. The 31 day frequency takes into
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consideration the gradual nature of gas accumulation in the ECCS piping and the i
adequacy of the procedural controls goveming system operation.
The Surveillance Requirements provided to ensure OPERABILITY of each component ensure that at a minimum, the assumptions used in the safety analyses are met and that subsystem OPERABILITY is maintained. Surveillance Requirements for throttle valve position stops and flow balance testing provide assurance that proper _
ECCS flows will be maintained in the event of a LOCA. Maintenance of proper flow resistance and pressure drop in the piping system to each injection point is necessary to: (1) prevent total pump flow from exceeding runout conditions when &ie system is in its minimum resistance configuration, (2) provide the proper flow split between injection points in accordance with the assumptions used in the ECCS-LOCA analyses, and (3) provide an acceptable level of total ECCS flow to all injection points equal to or above that assumed in the ECCS-LOCA analyses. The requirement to dissolve a representative sample of TSP in a sample of water borated to be representative of post-LOCA sump conditions provides assurance that the stored TSP will dissolve in borated water at the postulated post-LOCA temperatures.
The requirement to verify the minimum pump discharge pressure on recirculation flow ensures that the pump performance curve has not degraded below that used to show that the pump exceeds the design flow condition assumed in the safety analysis and is consistent with the requirements of ASME Section XI.
WATERFORD - UNIT 3 B 3/4 5-2
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l EMERGENCY CORE COOLING SYSTEMS 1
i BASES 3/4.5.4 REFUELING WATER STORAGE POOL (RWSP) l I
i The OPERABILITY of the refueling water storage pool (RWSP) as part of the ECCS also ensures that a sufficient supply of borated water is available for injection by the ECCS in the event of a LOCA. The limits on RWSP minimum volume and boron concentration ensure that (1) sufficient water is available within containment to permit recirculation cooling flow to
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the core, and (2) the reactor will remain subcritical in the cold condition following mixing of the i
i RWSP and the RCS water volumes with all CEAs inserted except for the most reactive control
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assembly. These assumptions are consistent with the LOCA analyses.
1 The contained water volume limit includes an allowance for water not usable because l
of pool discharge line location or other physical characteristics.
j The lower limit on contained water volume, the specific boron concentration and the physical size (approximately 600,000 gallons) of the RWSP also ensure a pH value of between 4
j 7.0 and 11.0 for the solution recirculated within containment after a LOCA. This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.
The maximum limit on the RWSP temperature ensures that the assumptione used in i
the containment pressure analysis under design base accident conditions remain valid and l
avoids the possibility of containment overpressure. The minimum limit on the RWSP j
temperature is required to prevent freezing and/or boron precipitation in the RWSP.
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WATERFORD - UNIT 3 B 3/4 5-3
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