ML20085N032
| ML20085N032 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 11/07/1991 |
| From: | VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| Shared Package | |
| ML20085N030 | List: |
| References | |
| NUDOCS 9111140019 | |
| Download: ML20085N032 (12) | |
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1 Completed Version of Proposed Changes t
- North Anna Units 1 and 2 3
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s PLANT SYSTEMS 3'4.7.13 GROUNDWATER LEVEL SERVICE WATER RESERVOIR UMITING CONDITION FOR OPERATION 3.7.13 The groundwater lovel of the service water reservolt (shared by Units 1 and 2) l shall not exceed the elevation at the locations listed in Tablo 3.7 6. The flow of groundwater from the drains beneath the pumphouse shall not excood the values given in Table 3.7 6.
APPLICABILITY:
ALL MODES.
ACTION.
- a. With the groundwater lovel of the service water reservolt or the groundwater flow rate exceeding any of the limits of Table 3.7 6, an engineering evaluation shall be performed by a Licensed Civil Engincor to determino the cause of the high ground water or flow rates and the influence on the stability of the service water reservoir and pumphouse. A Special Report shall be prepared and submitted to the Commission pursuant to Specification 6.9.2 within 90 days, containing the results of the evaluation and any corrective action determined to be necessaly,
- b. With the inability to obtain at least one measurement from each of the locations listed in SR 4.7.13.1, an engineering evaluation shall be performed by a Licensed Civil Engineer to determine the consequences of not meeting SR 4.7.13.1. A Special Report shall be prepared and submitted to the Commission pursuant to Specification 6.9.2 within 90 days, containing the results of the evaluation and any corrective action determined to be necessary,
- c. The provisions of Specification 3.0.4 are not applicable.
SURVElLLAtCE REQUIREMENTS 4.7.13.1 At least once por six months verify the groundwater level within the dike of the service water reservoir does not exceed the value established in Tablo 3.7 6.
The groundwater level shall be determined by measurement from each zone. At a minimum, at least one measuromont shall be mado at each zone listed below and the measurement shall be within the limits presented in Table 3.7 6:
service water pump house (Nos.11,14 or 20), and south east end of the reservoir (Nos. 10,15, 21 or 22), and a-service water valve house (Nos.18 or 19) 4.7.13.2 At least once per six months verify that the groundwater flow rate does not exceed the value established in lable 3.7 6. The groundwater flow rato shall be determined by measurements at the drain outlet gallery. A visualinspection of the clarity of the outflow from each drain shall be performed in conjunction with the flow monitoring effort.
y NORTH ANNA UNIT 1 3/4 7 73
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I TABLE 3.7-6 s
ALLOWABE GROLNDWATER LEVn L SERVCE WATER RESERVOtR C
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PEASUR9ENT A110WABEGRO'JNDWATER EEVATON, l
NO.
LOCATON Mean sea level (feet) 10 SE, toe 277 11 SWPH, (Units 1 & 2) crest 280 14 SWPH, (UNITS 1 &2) crest 280 co E
- 15 SE crest 280 18 SWVH, (Units 1 & 2) 295 19 SWVH, crest 295 20 SWPH, crest 280 21 SE, crest 280 i
22 SE, crest 280 ALIDNABLE DRAN FLOW RATE DRAN OUTLETS LOCATION faallons ner minutel 1 through 6 Drainage Ga!!ery FLCr#RATESHALLNOTEXCEED 8_5 GALLONS PER MINUTE (gpm)
PLANT SYSTEMS (MSES r
3'4.7.13 GROUNDWAi 2R LEVEL-SERVICE WATER RESERVOIR A program to monitor groundwater levels in the area of the service water reservoir has boon ostablished to ensure that the integrity of the service water reservoir embankmonts and pumphouse is maintained.
Groundwater threshold lovels have been established based on historical groundwater data available in 1977. These lovels are sufficiently conservative to ensure that the service water reservoir and pumphouso v'ill perform their intend 1d function. An engineering evaluation will be performed if these threshold values are excooded, to dolormino if thoro is any substantive cause to believe that any aspect of the service water reservoir, diko, or pumphouse will not perform its intended function. A conclusion to this offect, and the appropriato corrective actions to be performed, will be reported to the Commission.
A minimum of one measuromont devico in cach of the throo zones is toquired to be OPERABLE in order to monitor the groundwater levels. The groundwater levels are periodically reviewed to dolormine whether a changing groundwater environment warrants a chango in threshold levels.
w NORTH ANNA UNIT 1 B 3/4 7 9 l
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PLANT SYSTEMS 3'4.7.13 GROUNDWATER LEVEL SERVICE. WATER RESERVOIR UMITING CONDITION FOR OPERATION 3.7.13 The groundwater lovel of the service water reservoir (shared by Units 1 and 2) l shall not uxceed the elevation at the locations listed in Table 3.7 6. The flow of groundwater from the drains boncath the pumphouse shall not exceed the values given in Tablo 3.7 6.
APPLICABILITY:
All. MODES.
AGIDN.
- a. With the groundwater lovel of the servico water reservolt or the groundwater flow rato excooding any of the limits of Tablo 3.7 6, an engineering ovaluation shall be performod by a Licensod Civil Engineer to dolormino the cause of tho high ground water or flow ratos and the influence on the stability of the service water reservolt and pumphouse. A Special Report shall be preparod and submitted to the Commission pursuant to Specification 6.9.2 within 90 days, containing the results of the ovaluation and any correctivo action dotermined to be nocessary,
- b. With the inability to obtain at least one measuromont from each of the locations listed in SR 4.7.13.1, an engincori,3 ovaluation shall be performed by a Uconced Civil Engineer to dolormlne the consequences of not mooting SR 4.7.13.1. A Special Report shall bo prepared and submittod to the Commission pursuant to Specification 6.9.2 within 90 days, containing the results of tho evaluation and any correct!vo action datormined to be necessary,
- c. The provisions of Specification 3.0.4 are not applicable.
SURVEILLANCE REQUIREMENTS 4.7.13.1 At least once per six rnonths vorify the groundwater level within the diko of the service water reservoir does not exceed the value established in Tablo 3.7 6. The groundwater lovel shall be dolorminod by measutomont from each zono. At a minimum, at least one measurement shall be mado at each zone listed below and the measurement shall be within the limits presented in Table 3.7 6:
service water pump house (Nos.11,14 or 20), and south east end of the reservoir (Nos. 10,15, 21 or 22), and a
service water valve house (ks.18 or 19) 4.7.13.2 At least once por clx months verify that the groundwater flow rate does not exceed the 1
L value established in Table 3.7 6. The groundwater flow rato shall be dolormined by measutoments at the drain outlet gallery. A visualinspection of the clarity of tho outflow from each drain shall bo,porformed in conjunction with the flow monitoring i
effort.
NORTH ANNA UNIT 2 3/4 7 57 l
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I TABLE 3.7-6 l
E AW.DWABLE GROUNDWATER LEVA R - SERVICE WATER REN-L CZw DEVICE MEASUREMENT ALLOWABGGROUNDWATER ELEVATION.
l NO.
LOCATION Mean sea level (feen 10 SE. toe 277 11 SWPH. (Units 1 & 2) crest 280 14 SWPH, (UNITS 182) crest 280 ca R
15 SE ast 280 y
18 SWVH, (Units 1 & 2) 295 cn
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19 SWVH crest 295 20 SWPH, crest 280 21 SE crest 280 22 SE crest 280 AllOWABE DRAN FLOW RATE DRAN OUTLETS LOCATQ{
fealbns ner mintMe) 1 through 6 Drainage Ga!!ery FLOW RATESWd.LNOTEXCEED o
8.5 GALLONS PER MINUTE (gpm) o
PLANT SYSTEMS MSES 3'4.7.13 GROUNDWATER LEVEL-SERVICE WATEH RESERVOIR A program to rnonitor groundwater levels in tho area of the service water reservoir has boon established to ensure that the intogrity of the service water reservoir embankments and pumphouse is maintained.
Groundwater threshold lovels have boon established based on historical groundwater data available in 1977. These levola are sufficiently conservativo to ensure that the servico water reservoir and pumphouse will perform tholt intendcd function. An engincoring evaluation will be performed if those threshold values are excoodod, to determino if thoro is any substantivo cause to bollove that any aspect of the service water reservoir, dike, or pumphouse will not perform its intended function. A conclusion to this offect, and the appropriato corrective actions-to be performed, will be reported to the Commission.
. A minimum of one measutomont device in each of the throo zones is required to be OPERABLE in order to monitor the groundwater levels. The groundwater lovels are periodically reviewed to dolormine whether a changing groundwater environment warrants a change in threshold lovels.
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NORTH ANNA UNIT 2 B 3/4 7 9
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10 CFR. 50.92,. No S10nificant Hazards Consideration North Anna Units 1 and 2 Virginia-Electric and Power Company
10 CFR 50.92 Significant Hazards Considerations Analysis The proposed changes described herein are being made as a result of tho replacement of several piezometers with open tubo devices that use a conductivity cell. These devices were installed under design change package DCP 90 0013," Service Water Reservoir Addition."
The phrase "(common to Units 1 and 2)" is added to the Limiting Condition for Operation for Unit 1 only for consistency with the current Unit 2 Specification.
The Action statement has been separated into 3.7.13.a and 3.7.13.b and changed to explicitly state that if et least one measurenient from each of the zones listed in SR 4.7.13.1 can not be obtained, then a special report should be prepared and submitted to the Commission within 90 days.
Because Action 3.7.13.b specifically addresses not being able to complete S.R. 4.7.13.1 and does not require a reduction in Modes, Action statement 3.7.13.c has been added to specify that the provisions of Specification 3.0.4 are not applicable.
Surveillance Requirement 4.7.13 is divided into two parts, 4.7.13.1 for grcundwater level determination, and 4.7.13.2 to measure the outflow of groundwater from the drainage galleries.
Both of these requirements are currently presented in Specification 4.7.13.1. These changes enhance clarity and will provide flexibility in the Surveillance Requirement, it is not necessary to monitor all of the measurement locations in order to detect an increasing rate of seepage from the reservoir. An engineering evaluation was performed in DCP 90 0013 showing that a reliable reading from one location in each of the three zones of the dike (the pump house, valve house and the southeast side of the reservoir) is sufficient for detecting leakage from the reservoir. However, the Periodic Test procedure will continue to require that all OPERABLE measurement locations be monitored in order to obtain as much information as possible.
Table 3.7 6 deletes the piezometers that were removed under DCP 90 001 3 and adds the replacement measurement devices that were installed under the same design change package.
The replacement devices are of an open tube design which responds more slowly to changing water levels than the original pneumatic piezometers that were removed, Although the pneumatic type piezometers are better suited for measuring rapidly changing groundwater levels, groundwater levels have historically fluctuated slowly, responding to the seasonal variation in rainfall since the installation of the horizontal drains beneath the pump house and the
. trench drain which is located at the southeastern toe of the dike. Such slow fluctuations can be readily monitored by open tube devices. Out flow from the drainage galleries drain outlets, which may not exceed the Technical Specification Table 3.7-6 limit of 8.5 gallons per minute, can be used to detect a rapidly increasing leakage situation.
It has a been determined that the atoposed changes do not involve a significant hazards consideration as definec in 10 CFR 50.92. This determination was based on the following points.
1.
Accident Probability or Consequence increase.
The proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated, Sufficient means for detecting high water levels within the dike will still be required by the Technical Specifications. Also, the changes require that at least one piezometer or open tube device must be OPERABLE in each of the three main zones of the dike.
2.
Accident Possibility Creation. Operation with these changes does not create the possibility of a new or different kind of accident from any accident previously evaluated. The proposed changes do not involve any changes to plant design and a sufficient means for detecting high water levels within the dike will still be required by *he Technical Specifications proposed herein. Also, the changes require thus at least one piezometer or open tube device must be OPERABLE in each of the three main zones of the dike.
3.
Safety Margin Reduction. The proposed changes do not involve a significant reduction in the margin of safety. The changes proposed heroin acknowledges that some of the piezometers have become inoperable over time and have been replaced by open tube devices.
The proposed-changes also specify that measurements from each of the three main zones of the dike will be obtained to determine that groundwater levels within the dike are below allowable elevations. Therefore, the proposed
-changes do not involve a reduction in the margin of safety.
Based.on the above significant hazards consideration evaluation, Virginia Electric and Power Company concludes that the activltles associated with this proposed Technical Specification change satisfies the no significant hazards consideration standards of 10 CFR 50.92(c) and, accordingly, a no significant hazards consideration finding is justified.
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l to further cool the units is available, unit cooldown shall continue until COLD SHUTDOWN is achloved under Action statement 3.7.3.1.b.
This Action statement is consistent with MERITS.
1 Survolilance Requirement 4.7.3.1.a was modified to replace " safety related l
equipment" with "in the flow path of the residual heat removal system" for clarity.
Surveillance Requirement 4.7.3.1.b was added to specify surveillance testing for OPERABILITY determination of the component cooling water pumps in accordance with Specification 4.0.5, the ASME Section XI program.
Technical Soecification 3.7.3.2 This Technical Specification was added to support our current UFSAR design bases when both units are in Modes 5 or G.
A new Limiting Condition for Operation is established for modec 5 and 6. This now limiting Condition differs from Specification 3.7.3.1 by requiring that two of the four component cooling water subsystems be OPERABLE. Component cooling water is required to provide a heat sink for the residual heat removal system to remove decay heht from the reactor core. However, there is a significant reduction in potential heat loading on component cooling water with the reduced operational requirements of the other systems that are cooled by component cooling water. The major reduction in heat loads is due to the fact that by mode 5 reactor decay heat has already dropped off significantly and that reactor coolant pumps and control rod drive mechanisms are not reaulred to be operating in modes 5 and 6.
Therefore, only two component cooling water subsystems are required to be OPERABLE.
If only one of the two required component cooling water subsystems is OPERABLE, Action Statement 3.7.3.2 requires all operations involving an increase in the reactor decay heat load or a reduction in boron concentration of the Reactor Coolant System must be immediately suspended.
This is consistent with the action requirements for a totalloss of residual heat removal capability during shutdown conditions.
The Surveillance Requirements are the same as those of Specification 3.7.3.1.
Bases Sections 3/4.7.3.1 and 3/4.7 3.2 The existing bases section (3/4.7.3) was expanded to provide a more detailed description of the component cooling water system. Tnis bases section was also split to provide a description for operating and shutdown conditions (3/4.7.3.1 and 3/4.7.3.2, respectively).
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to further cool the units is available, unit cooldown sha'l continua until COLD SHUTDOWN is achieved under Action statement 3.7.3.1.b.
This Action statement is consistent with MERITS.
Surveillance Requirement 4.7.3.1.a was modified to replace " safety related equipment" with "in the flow path of the residual heat removal system" for clarity.
Surveillance Requirement 4.7.3.1.b was added to specify surveillance testing for OPERABILITY determination of the component cooling water pumps in accordance with Specification 4.0.5, the ASME Section XI program.
Technical Soecification 3.7.3.2 This Technical Specification was added to support our current UFSAR design bases when both units are in Modes 5 or 6.
A new Limiting Condition for Operation is established for modes 5 and 6. This new Limiting Condition differs from Specification 3.7.3.1 by requiring that two of the four component cooling water subsystems be OPERABLE Component cooling water is required to provide a heat sink for the residual heat removal system to remove decay heat from the reactor core. However, there is a significant reduction in potential heat loading on component cooling water with the reduced operational requirements of the other systems that are cooled by component cooling water. The major reduction in heat loads is due to the fact that by mode 5 reactor decay heat has already dropped off significantly and that reactor coolant pumps and control rod drive mechanisms are not required to be operating in modes 5_and 6. Therefore, only two component cooling water subsystems are required to be OPERABLE.
lf only one of the two required component cooling water subsystems is OPERABLE, Action Statement 3.7.3.2 requires all operations invulving on increase in the reactor decay heat load or a reduction in boron concentration of the Reactor Coolant System must be immediately suspended.
This is consistent with the action requirements for a totalloss of residual heat removal capability during shutdown conditions.
The Surveillance Requirements are the same as those of Specification 3.7.3.1.
Bases Sections 3/4.7.3.1 and 3/4.7.3.2 The existing bases section (3/4.7.3) was expanded to provide a more detailed description of the component cooling water system. This bases section was
-also split to provide a description for operating and shutdown conditions (3/4.7.3.1 and 3/4.7.3.2, respectively),
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