ML20059B153
| ML20059B153 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee  |
| Issue date: | 10/22/1993 |
| From: | VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | |
| Shared Package | |
| ML20059B151 | List: |
| References | |
| NUDOCS 9310280052 | |
| Download: ML20059B153 (15) | |
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Attachment A Summary of Technical Snecification Chances Delete the following pages: Insert the followinc nages:
34a 34a 39a 39a 40 40 53a 53a.
63 63 79 79 79a 79a 80 80 ;
- 80a t
- 80b 81 81 !
83 83 83a ,
84 84 l
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.I 1 9310280052 931022 -l PDR ADOCK 05000271 h'3 .j P PDR g l
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VYNPS 3.2 LIMITING CONDITIONS FOR OPERATION 4 .' 2 SURVEILLANCE REQUIREMENTS
- 1. Recirculation Pump Trio and Alternate Rod I. Recirculation Pump Trio and Alternate Rod Insertion Instrumentation Insertion Instrumentation During reactor power operation, the The Recirculation Pump Trip and Alternate Rod Recirculation Pump Trip and Alternate Rod Insertion Instrumentation shall be Insertion Instrumentation shall be operative functionally tested and calibrated in in accordance with Table 3.2.1. accordance with Table 4.2.1.
I J. Deleted J. Deleted K. Degraded Grid Protective System K. Oegraded Grid Protective Systeu During reactor power operation. the emergency The emergencyo 'us undervoltage i bus undervoltage instrumentation shall be instrumentation shall be functionally tested operative in accordance with Table 3.2.8. and calibrated in accordance with Table 4.2.8.
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L. Reactor Core Isolation Cooling System L. Reactor Core Isolation Cooling System Actuation Actuation ;
When the Reactor Core Isolation Cooling Instrumentation and logic Systems shallibe System is required in accordance with functionally tested and calibrated as Specification 3.5.G. the instrumentation indicated in Table 4.2.9.
which initiates actuation of this system shall be operable in accordance with Table 3.2.9.
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Li 34a-LAmendment No. 58. 96. 98. +++. ISE
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VYNPS TABLE 3.2.1 RECIRCULATION PUMP TRIP AND ALTERNATE ROD INSERTION ACTUATION INSTRUMENTATION t
Recirculation Pump. Trip and Alternate Rod Insertion - A & B (Note 1)
Minimum Number of Required Action When -
Operable Instrument Minimum Conditions Channels per Trip for Operation System Trio Function Trio level Setting Are'Not Satisfied 2 Low-Low Reactor Vessel Water 26* 10.5" above top of Note 2 7 Level enriched fuel 2 High Reactor Pressure s1150 psig Note 2 i
2 Time Delays s10 seconds Note 2 1 Trip Systems Logic --
Note 2
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Amendment No 50, 60, 70. 75 39a-
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VYNPS TABLE 3.2.1 NOTES
- 1. Each of the two core spray LPCI, Alternate Rod 'nsertion, and Recirculation Pump Trip, subsystems are '
initiated and controlled by a trip system. The Subsystem "B" is identical to the Subsystem "A".
If the minimum number of operable instrument channels is not available, the inoperable channel shall i
- 2. If the channel cannot be tripped !
be tripped using test jacks or other parmanently installed circuits.
by the means stated above, that channel shall be made operable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or an orderly shutdown shall be initiated and the reactor shall be in the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
- 3. One trip system with initiating instrumentation arranged in a one-out-of-two taken twice logic.
- 4. One trip system with initiating inst sentation arranged in a one-out-of-two logic.
- 5. If the minimum number of operable channels is not available, the system is considered inoperable and the requirements of Specification 3.5 apply.
- 6. Any one of the two trip systems'will. initiate' ADS. If the minimum number of operable channels in one-trip system is not available, the requirements of Specifications 3.5.F.2 and 3.5.F.3 shall apply. If the minimum number of operable channels is not available in both trip systems. Specification 3.5.F.3 shall apply.
- 7. One trip system arranged in a two-out-of-two logic.
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Amendment No. 50 401 l
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VYNPS TABLE 4.2.1 (Continued)
Recirculation Pump Trip and Alternate Rod Insertion Actuation System Trio Function Functional Test (8) Calibration (8) Instrument Check (Note 1) Once/ Operating Cycle Once Each Day Low-Low Reactor Vessel Water Level (4)
(Note 1) Once/ Operating Cycle Once Each Day l
High Reactor Pressure (4)
Trip System Logic Once/ Operating Cycle Once/ Operating Cycle --
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53a-Amendment No. 58 M 6
VYNPS BASES: 3.2 (Cent *d) s The low-low reactor water level instrumentation is set to trip when reactor water level is 82.5" H O 2 indicated on the reactor water level instrumentation above the top of the enriched fuel. This trip initiates closure of the Group 1 primary containment isolation valves and also activates the ECCS. ,
ARI. RPT, and RCIC System and starts the standby diesel generator system. This trip setting level l- ,
was chosen to be low enough to prevent spurious operation, but high enough to initiate ECCS operation. ARI. RPT and primary system isolation so that no melting of the fuel cladding will occur j ,
and so that post-accident cooling can be accomplished and the limits of 10CFR100 will not be !
violated. For the complete circumferential break of 28-inch recirculation line and with the trip setting given above. ECCS initiation. ARI. RPT and primary system isolation are initiated in time l to meet the above criteria. The instrumentation also covers the full range of spectrum breaks and ,
meets the above criteria.
The high drywell pressure instrumentation is a backup to the water level instrumentation and in addition to initiating ECCS it causes isolation of Group 2. 3. and 4 isolation valves. For the complete circumferential break discussed above. this instrumentation will initiate ECCS operation at ;
about the same time as the low-low water level instrumentation, thus the results given above are l applicable here also. Group 2 isolation valves include the drywell vent, purge, and sump isolation valves. High drywell pressure activates only these valves because high drywell pressure could occur as the result of non-safety-related causes such as not purging the drywell air during startup.
Total system isolation is not desirable for these conditions and only the valves in Group 2 are i i
required to close, The water level instrumentation initiates protection for the full spectrum of loss-of-coolant accidents and causes a trip of all primary system isolation valves. ,
Venturis are provided in the main steam-lines as a means of measuring steam flow and also limiting the loss of mass inventory from the vessel during a steam line break accident. In addition to monitoring steam flow, instrumentation is provided which causes a trip of Group 1 isolation valves.
The primary function of the instrumentation is to detect a break in the main steam line, thus only Group 1 valves are closed. For the worst case accident, main steam line break outside the drywell, c this trip setting of 140 percent of rated steam flow in conjunction with the flow limiters and main steam line valve closure limit the mass inventory loss such that fuel is not uncovered, cladding temperatures remain less than 1295*F .and release of radioactivity to the environs is well below 10CFR100. ,
k Temperature monitoring instrumentation is provided in the main steam line tunnel to detect leaks in ,
this area. Trips are provided on this instrumentation and when exceeded cause closure of Group.1 l isolation valves. Its setting of ambient plus 95'F is low enough to detect leaks of the order of 5 tot 10 gpm: thus, it is capable of covering the entire spectrum of breaks. For large breaks.~it is
! a backup to high steam flow instrumentation discussed above, and.for'small breaks with the resultant i small release of radioactivity, gives isolation before the limits of 10CFR100 are exceeded.
i Amendment No. 50, 66. 66, 14+ 63-
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4 VYNPS 3.4 LIMITING CONDITIONS FOR OPERATION 4.4 SURVEILLANCE REQUIREMENTS .
3.4 REACTOR STANDBY LIQUID CONTROL SYSTEM 4.4 REACTOR STANDBY LIQUID CONTROL SYSTEM Applicability: Applicability:
4 Applies to the operating status of the Reactor Applies to the periodic testing requirement for Standby Liquid Control System. the Reactor Standby Liquid Control System. ,
Objective: Objective:
To ensure the availability of an independent To verify the operability of the Standby Liquid reactivity control mechanism. Control System. .
" Specification: Specification:
A. Normal Operation A. Normal Operation
, Except as specified in 3.4.B below, the The Standby Liquid Control System shall be Standby Liquid Control System shall be verified operable by:
operable during periods when fuel is in the reactor unless: 1. Testing pumps and valves in accordance '
with Specification 4.6.E. A minimum
- 1. The reactor is in cold shutdown, flow rate of 35 gpm at 1275 psig shall be verified for each pump by
, and recirculating demineralized water to the test tank. . .
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- 2. Control rods are fully inserted and .
Specification 3.3.A is met. 2. At'least monthly, determining the .
sodium pentaborate concentration of the' solution in the liquid poison tank.
Concentration shall also be determined within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.following the addition of water or baron. The sodium pentaborate concentration-(C) shall satisfy the following equation for normal operation:
C 210.1%
- 19.8%
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i Amendment No. 402. HB 79'
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3,4 LIMITING CONDITIONS FOR OP[ RATION 4.4 SURVEILLANCE REQUIREMENTS where:
10.1% - Original design bases sodium pentaborate concentration based on naturally enriched sodium- l pentaborate solution.
(19.8 atom % of total: boron being the isotope B-10.)
19.8% = Vermont Yankee original design bases Boron-10 enrichment (natural enrichment) of the sodium pentaborate solution in atom percent.
E - Latest tested Boron-10 enrichment of the sodium pentaborate solution in atom -
percent.
- 3. Verifying the continuity.of the explosive charges at least monthly.
In addition, at least once during each operating cycle, the Standby Liquid Control l System shall-be verified operable by:
- 1. . Testing that the setting of the pressure relief valves is between 1400 and 1490 psig.
Amendment No. 402, 79a 4
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VYNPS 4.4 3.4 LIMITING CONDITIONS FOR OPERATION SURVElllANCE REQUIREMENTS
- 2. Initiating one of the star.dby liquid?
control-loops, excluding the primer chamber and inlet fitting, and-verifying that a flow path from a pump to the reactor vessel is available by pumping demineralized water into the reactor vessel. Both loops.shall be tested over the course of two operating, cycles.
- 3. Testing the new trigger assemblies by installing one of the assemblies in the-test block and firing it using the
! installed circuitry. . Install the unfired assemblies, taken from the same .'
batch as the fired one, into the explosion valves.
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- 4. Recirculating the borated solution.
B. Operation With Inoperable Components B. Operation With Inoperable Components When a component becomes= inoperable, its From and after the date that a redundant redundant component shall be or shall have component is made or found to be inoperable, been demonstrated to be operable within reactor operation is permissible during the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
succeeding seven days unless such component' i is sooner made operable.
C. Liould Poison Tank - Volume and Temperature C. Liouid Poison Tank - Volume and Temperature l
At all times when the Standby Liquid Control 1. The solution volume and temperature in System is required to be operable. the the tank =shall be checked at least following conditions shall be met: daily.
The liquid poison tank shall contain a 2. If the solution temperature drops below minimum of 3,850 gallons and a maximu,m of the limits specified-by Figure 3.4.2, 4,830 gallons of boron bearing solution, the sodium pentaborate concentration-shall be determined.
The solution temperature, including that in the pump suction piping, shall not be less than the temperature presented in Figure 3.4.2. ,
i Amendment No. M. M.10B. M4 80
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VYNPS 3.4 LIMITING CONDITIONS FOR OPERATION 4.4 SURVEILLANCE REQUIREMENTS -
ATWS Rule Eauivalence Equation D. ATWS Rule Eauivalency Ecuation D. ,
The Standby Liquid Control System must 1. Baron enrichment shall be tested and.
satisfy one of the following equations for verified prior to each scheduled ATWS compliance or invoke startup from refueling.
Specification 3.4.G.:
- 2. ATWS equivalency shall be determined after each test of pump flow rate.
86 gpm solution concentration, or solution MVY 13% Wt E 219.8% * *
- enrichment.
M251 C 0 ,
O 2 86 gpm . MVY , 13% Wt ,19.8%
M251 C E C 213% Wt *
- 86 gpm ,19.8%
M251 0 E where:
E = Boron-10 enrichment of the sodium pentaborate solution (atom percent). (See note below.)'
M yy - Mass of water at hot operating conditions. -Myy .401.247 lbs (nominal). 1 M 251 - Mass of water in reference plant at hot operating conditions.
M251 628.300 lbs (nominal)
C - Sodium pentaborate concentration in the solution storage tank it weight percent. (See note below.)l ;
)
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- r Amendment No. 80a
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'3.4 -LIMITING CONDITIONS FOR OPERATION 4.4 SURVEILLANCE REQUIREMENTS 0 - Flow rate of one pump. (See note below.)
' 13% Wt - Reference plant sodium pentaborate solution concentration, weight percent.
86 gpm - Injection flow for the reference plant.
19.8% = Reference plant and Vermont Yankee original design basis Boron-10 enrichment of the sodium pentaborate solution in atom percent.
Note: The latest test values for E. C. and 0 should be used in the ATWS .I equivalency equation. ]
E. If Specifications 3.4.A or 3.4.B are not met. an orderly shutdown shall be' initiated and the' reactor shall be in the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
F. If Specification 3.4.C is not met, action shall be immediately initiated to correct j
l the deficiency. If at the end of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> the system has not been restored to full operability, then a shutdown shall be j initiated with the reactor in cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of initial discovery.
G. If Specification 3.4.D'is not met, action l l shall be taken to bring the specification I
into compliance within seven days. If af ter i seven days the specification is still/not in l
compliance, the NRC'shall be notified withinL 'q the following seven days. The notification ' l shall include the plans necessary to bring the specification.into compliance.
i Amendment No. 80b
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VYNPS Figure 3.4.1 This figure has been deleted.
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l 81 l: ' Amendment No.
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VYNPS BASES:
3.4 & 4.4 REACTOR STANDBY LIQUID CONTROL SYSTEM .
- A. Normal Operation The design objective of the Reactor Standby Liquid Control System is to provide the capability of bringing the reactor form full power to a cold xenon-free shutdown assuming that none of the withdrawn control rods can be inserted. To meet this objective, the Liquid Control System is designed to inject a quantity of boron, of which at least 19.8% must be the isotope Boron-10, which produces a ~l -
i concentration of 800 ppm of boron in the reactor core in less than 138 minutes. 800 ppm boron l concentration in the reactor core is required to bring the reactor from full power to a 5% Ak -
I subcritical condition. An additional margin (25% of boron) is added for possible imperfect mixing of the chemical solution in the reactor water. A minimum quantity of 3850' gallons of solution having a 10.1% sodium pentaborate concentration is required to meet this shutdown requirement.
The Reactor Standby Liquid Control System is also required to meet the regulatory objective. '
10CFR50.62. " requirement for reduction of risk from Anticipated Transients Without Scram (ATWS) events for light water-cooled nuclear power plants." The basic method for achieving compliance is to increase the inventory of the isotope Boron-10 by increasing the enrichment of the sodium pentaborate ,
solution (refer to bases D. ATWS Rule-10CFR50.62). In doing so, an increase in the solution -;
enrichment above 19.8% can reduce the minimum solution concentration accordingly and ensure sufficient Boron-10 is available to meet the design objective of the Reactor Standby Liquid Control System.
Satisfying the equation C 2 10.1%
- 19.8% / E (where C - concentration as tested and E - enrichment as tested) ensures that this amount of Boron-10 is present to fulfill the system design objective.
lne time requirement (138 minutes) for insertion of the baron solution was selected to override the rate of reactivity insertion due to cooldown of the reactor following the xenon poison peak. For a a required pumping rate of 35 gallons per minute, the maximum net storage volume of the boron solution is established as 4830 gallons.
Baron concentration, solution temperature, and volume are checked on a frequency to ensure a high reliability of operation of the system should it ever be required. Experience with pump operability indicates that testing in accordance with Specification 4.6.E is adequate to' detect if failures have occurred. Flow. relief valve. circuitry, and trigger assembly testing at the prescribed intervals assures a high reliability of system' operation capability. Pump operability is' checked at a frequency to ensure a high reliability of operation of the system should it ever be required. Recirculation of the borated solution is done during each operating cycle to ensure one suction line from the boron tank is clear. -Flow tests at refueling intervals ensure that the complete piping system is capable of
< sustaining the required flow rate.
A v
Amendment No. W2. 20 - 83
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4 VYNPS BASES: 3.4 & 4.4 (Continued)
B. Operation With inoperable Components Only one of the two standby liquid control-pumping circuits is needed for proper operation of the system. If one pumping circuit is found to be inoperable, there is no immediate threat to shutdown capability, and reactor operation may continue while repairs are being made. Assurance that the system will perform its intended function is obtained from the results of the pump and valve testing performed in accordance with ASME Section XL requirements. Whenever one redundant component is- -
3 inoperable, the potential for. extended operation with two subsystems inoperable is reduced by requiring that the redundant component be tested within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
C. Licuid Poison Tank - Boron Concentration The solution saturation temperature varies with the concentration of sodium pentaborate. To guard against boron precipitation due to low temperature, the solution shall be kept at least 10*F above the saturation temperature. The 10*F margin is included in Figure 3.4.2. 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 unless the solution temperature is below saturation temperature or more boron or more-water is added. Level and temperature indication and alarms indicate whether the solution volume or temperature has changed which might indicate a possible solution concentration change. Considering these factors, the test interval has Deen established.
Sodium pentaborate concentration is determined monthly and within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the addition of water-or boron, or if the solution temperature drops below specified limits. The 24-hour limit allows for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of mixing, subsequent testing, and notification of shift.
D. ATWS Rule - 10CFR50.62 The regulatory objective of the Standby Liquid Control System is to meet 10CFR50.62 (requirements for reduction of risk from Anticipated Transients Without Scram ( ATWS) . events for light water-cooled nuclear power plants). The Standby Liquid Control System must have the equivalent control capacity t-o an 86 gpm system of 13% Wt natural sodium pentaborate in order to satisfy 10CFR50.62 requirements.
This equivalency requirement is fulfilled by having a system which satisfies the equation given in Specification 3.4.D. This equation takes into account the nominal mass difference between the 251-inch reactor vessel reference plant and the VY 205-inch reactor vessel. Each parameter (concentration, pump flow rate, and enrichment) is tested at an interval consistent with the potential for that parameter to vary and also to ensure proper. equipment performance. -Concentration: testing is required when the solution tank temperature is.below specified limits or when chemical or water addition occurs since change cannot occur-by any process other than low solution temperature, the addition of new chemicals or demineralized water to-the standby liquid control solution tank.
Enrichment testing is only required prior to 'startup f rom refueling to. ensure a proper. amount of Boron-10 isotope while operating.
Amendment No. ME. -H4. 4EB 83a
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R VYNPS-
. BASES: 3.4 & 4.4 (Continued)
. The enriched sodium pentaborate solution is-made by adding prepared enriched sodium pentaborate crystals to demineralized water-or combining natural borax and enriched boric acid in stoichiometric '
quantities in demineralized water. Since the chemicals have known enrichments, the resulting enriched sodium pentaborate solution also has a known enrichment. Thus, concentration analysis is adequate for.
use in determining immediate compliance with Specification 3.4.0. The Boron-10 solution enrichment shall be verified by analysis to be above the minimum limit of Specification 3.4.D prior to startup from refueling. ,
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i Amendment No. 400, M 84
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