ML20195J443

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Proposed Tech Specs Re Revs to Allowable Groundwater Elevations & Removal of Piezometer Device Numbers Associated with Svc Water Reservoir
ML20195J443
Person / Time
Site: North Anna  Dominion icon.png
Issue date: 11/18/1998
From:
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML20195J440 List:
References
NUDOCS 9811240290
Download: ML20195J443 (15)
v • d • e


Text

. _____ ._ _ . _ , _ - _ . _ _ . _ _ . _ _ _..___.__________m .__

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Pt.ANTSYSTEMS 3/4 7.13 GROUNDWATER LEVEL SERVICE WATER RAERVOla i

j UMITING CONDITION FOR OPERATION 3.7.13 The groundwater level of the service water reservoir (shared by Units 1 and 2) shall not exceed the elevation at the locations listed in Table 3.7-6. The flow of groundwater $!

j trom the drains beneath the pumphouse shall not exceed the values given in Table 3.7 6.

APPUCABluTY: AU. MODES.

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a. With tha groundwater level of the service water reservoir or the groundwater

' flow rate exceedmg any of the limits of Table 3.74, an engineering evaluation y j

shall be performed by a Licensed CMI Engineer to determine 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 j

Commission pursuant to Specification 6.9.2 within 90 days, containing the results of the evaluation and any corrective action determined to be necessary.

1 i 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 Ucensed _7; '

l Civl Engmeer to determme the consequences of not meeting SR 4.7.13.1. A

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Special Report shal be prepared and submitted to the Commission pursuant to

} R+T-: E"-s 6.9.2 within 90 days, containing the results of the evaluation and

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any corrective action determined to be necessary.

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c. The provisions of SpEifk.stion 3.0.4 are not applicab's. )

! SURVElu.ANCE REOUIREMENTS

! 4,7.13.1 At least once per six months verify the groundwater level within the dka of the service water reservoir does not exceed the value established in Table 3.74.

The groundwater level shat! h* determined by measurement from each zone. At a 7

minimum, at least one measurement shall be made at each zone listed below and the measurement ViaN be within the limits presented in Table 3.74: (

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Eeus t- [ service water pump house (!'n.11,14 x 3^;. W y-3..a e soutCeast end of the reservoir (u _ 3 9, $ g, ;; g ;;;, g ,__

goue 3 service water valve house (!'- .13 ; 13) y )

4.7.13.2 . At least once per six months verify that tha groundwater flow rate does not exceed the value established in Table 3.74. The, groundwater flow rate shas be )

determined by measurements at the drain outlet gallery. A visual inspection of /\

the clarity of the outflow from each drain shall be performed in conjunction with the flow monitoring effort. f NORTH ANNA-UNIT 1 3/4 7 73 Amendment No. 12,57rnh 9811240290 98111e PDR ADOCK 05000338 P pop

._ . - - - - - - - =.- - - - - - -

2O_NE MEASUREME_N_T ALLSWATLE CROUNDWATE2 s LOCATION ELEVATION (Mean Sea Levelin feet) .:

1. Service Water Pump House Crest. 280 funits 1 & 21 al Crest 295
2. SouthJast corner of 280

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the SW Reservoir b) Toe y

3. Service Water Valve House Crest 295 tunlB 1 & 21 i ,

TABLE 57 8 fAainwAmt s afans sDAIATER LEvFI81 WATERfar T & a- e d ,a= = = 1 10 ,loe 277 '

11 SWMt. (Unlis 1 & 2) crest 280 SWPH, (UNITS 182) crest 280 <=:1.e 1

g yloc SE, crest

. 4 5 280 g -

? 13 SWVH, (Units 1 & 2) 295 M

$ s ke-te SWVH, crest 295 '

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  • 20 SWPH, crest 200 >

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21 SE, crest 2

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22 SE, crest 80

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satscz u*e4 RE55eurie. Aa e nwAsas F ORA 34 FMWV RATE I

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.E 1 gwougli e Drainage GaSery FIDWRATbtALLNOT EXCEED [

y S.5 GALLCNS PER MINUTE ;m..; i

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= 4  :

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Unit 2 North Anna Power Station Units 1 and 2 Virginia Electric and Power Company

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PLANT N i

! 3/4.7.13 GROUNDWATER LEVEL . SERVICE WATER RERERVOIR 1

) UMmNG CONotTION FOR OPERATION i

i 3.7.13 The groundwater level of the service water reservoir (shared by Units 1 and 2)  %

i shall not exceed the elevation at the locations listed in Table 3.7 6. The flow of groundwater /

l from the drains beneath the pumphouse shall not exceed the values given in Table 3.7 6.

i APPUCABILITY: ALLMODES.

1 ~

l AGI M:

a. With the groundwater level of the service water reservoir or the groundwater flow rate exceeding any of the limits of Table 3.7 6, an engineering evaluation [

shau be performed by a Ucensed Civil Engineer to determine 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 Specincation 6.9.2 within 90 days, containing the results of the evaluation and any corrective action determined to be necessary.

b. With the inability to obtain at least one measurement from each of the locations listed in SR 4.7.13.1 an angineering evaluation shaN be performed by a Ucensed

-7 Civu Engineer to determine the consequences of not meeting SR 4.7.13.1. A /

7 Special Report shal be prepared and submitted to the Commission pursuant to f SpK#@ 6.9.2 within 90 days, containing the results of the evaluation and any corrective action determined to be necessary. g

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c. The provisions of Specification 3.0.4 are not applicable. '

SURVElt.l.ANCE REQUIREMINTS 4.7.13.1 At least once per six months verify the groundwater level within the dike of the service water reservoir does not exceed the value established in Table 3.7 6. The -

r groundwater level shau be determined by measurement from each zone. At a mirumum, at least one measurement shas be made at each zone listed below and the /

7 measurement shaN be within the limits presented in Table 3.7 6: (

due.l.- service water pump house Ph.11,14 W 00), W4 y bm 2 - soutip and of the reservoir 7::.10,15,01 w 2), g4 p b.3 - service water valve house (M ?" r 10; y (

4.7.13.2 At least once per six months verify that the groundwater flow rate does not exceed the )

value ==tahant,ed in Table 3.7 4. The groundwater flow rate shad be determined by measurements at the drain outlet gallery. A visual inspecten of the clarity of the outnow from each drain shan beyectormed in conjunction with the now monitoring effort.

NORTH ANNA UNIT 2 3/4 7 57 Amendment No. M. t M",

._..._.-_..._.._...-.m. _. _ _ .... - . . . . _ .. . .. - ._. _ - ~ _ . .. _ - ..-- .. _ . . _ .. _ . . _ _ _. _

= v .

MEASUREMENT- ALL@WABLE CROUNDWATER

  • 2ONE ,-

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LOCATION ELEVATION (Mean Sea Levelin feet)

Crest 280 1 Service Water Pump House (Units 1 & 21 .,

295

2. SoutlTjast corner of al Crest ~!

280 i the SW Reservoir b) Toe Crest 295

- 3. Service Water Valve House M ABLE 17-8 A

  • p OpnasOAfATER LEwa 4 hcWATERWTM a -

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T ""A:" ..mm ys h i 10 toe 277 I

11 SWPH, (Units 1 & crest 280 l hicke SWPH, (UNITS 1 2) crest 280 i 14 Rerb ,

280 **#

Y 8 15 SE, crest I t

? 18 SWVH, ( s 1 & 2) 2 M  !

E 19 SWVH est 295 t

20 $ , crest 280 ,

21 , crest 280 g SE, crest f 280 k -

SaMV/<EuMEL ABEdNQt. - A3 ir1W#tt F DRAN FLOW RAIE m1N3EiD i

a -amsS - -

= -

. 1 re t. 8 or e G e ,

e@8.5 OWR.4-oorExcao GALLONS PER MINUTE (spwN r

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l Attachment 3 l

Proposed Technical Specifications Changes 1

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l-l l North Anna Power Station Units 1 and 2 Virginia Electric and Power Company 4

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Unit 1 1

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i North Anna Power Station Units 1 and 2 Virginia Electric and Power Company

PLANT SYSTEMS 3/4.7.13 GROUNDWATER LEVEL-SERVICE WATER RESERVOIR LIMITING CONDITION FOR OPERATION '

3.7.13 The groundwater level of the service water reservoir (shared by Units 1 and 2) shall not exceed the elevation at the locations listed in Table 3.7-6. The flow of groundwater from the drains beneath the pumphouse shall not exceed the values given in Table 3.7-6.

APPLICABILITY: ALL MODES.

ACTION:

a. With the groundwater level of the service water reservoir 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 Engineer to determine 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 necessary,
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. )

SURVEILLANCE REQUIREMENTS i

i 4.7.13.1 At least once per six months verify the groundwater level within the dike of the service water reservoir does not exceed the value established in Table 3.7-6. The groundwater level shall be determined by measurement from each zone. At a minimum, at least one measurement shall be made at each zone listed below and the measurement shall be within the limits presented in Table 3.7-6:

]

Zone 1 - service water pump house Zone 2 - southeast end of the reservoir Zone 3 - service water valve house 4.7.13.2 At least once per six months verify that the groundwater flow rate does not exceed the value established in Table 3.7-6. The groundwater flow rate shall be determined by measurements at the drain outlet gallery. A visual inspection of the clarity of the outflow from each drain shall be performed in conjunction with the flow monitoring effort.

NORTH ANNA - UNIT I 3/4 7-73 Amendment No. +2-5'h460,

i TABLE 3.7-6 SERVICE WATER RESERVOIR - ALLOWABLE GROUNDWATER LEVELS ALLOWABLE GROUNDWATER MEASUREMENT- ELEVATION ZONE LOCATION (Mean Sea Level in feet) i

1. Service Water Pump House Crest 280 l

- [ Units 1 & 2]

2. Southeast corner of the a. Crest 295 i SW Reservoir
b. Toe 280
3. Service Water Valve House Crest 295 i

[ Units 1 & 2] j l

SERVICE WATER RESERVOIR - ALLOWABLE DRAIN FLOW RATE l D'1AIN OUTLETS LOCATION FLOW RATE 1 through 6 Drainage Gallery Total Flow Rates shall not exceed 8.5 gallons per minute i

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1 NORTH ANNA - UNIT 1 3/4 7-74 Amendment No. 12,57,'17,160,

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~ ... .. . ..

It Unit 2 l.

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North Anna Power Station e!..

Units 1 and 2 j Virginia Electric and Power Company i

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a, x ..

45

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PLANT SYSTEMS I l

3/4.7.13 GROUNDWATER LEVEL-SERVICE WATER RESERVOIR l LIMITING CONDITION FOR OPERATION 3.7.13 The groundwater level of the service water reservoir (shared by Units 1 and 2) shall not exceed the elevation at the locations listed in Table 3.7-6. The flow of groundwater from the drains beneath the pumphouse shall not exceed the values given in Table 3.7-6.

APPLICABILITY: ALL MODES.

I ACTION- J l

a. With the groundwater level of the service water reservoir or the groundwater flow rate i exceeding any of the limits of Table 3.7-6, an engineering evaluation shall be performed l by a Licensed Civil Engineer to determine the cause of the high ground water or flow l 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 necessary.
b. With the inability to obtain at least one measurement from each of the locations listed in l

SR 4.7.13.1, an engineering evaluation shall be performed by a Licensed Civil Engineer l 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.

i SURVEILLANCE REQUIREMENTS l

4.7.13.1 At least once per six months verify the groundwater level within the dike of the service -l water reservoir does not exceed the value established in Table 3.7-6. The groundwater l level shall be determined by measurement from each zone. At a minimum, at least one l measurement shall be made at each zone listed below and the measurement shall be l within the limits presented in Table 3.7-6:

Zone 1 - service water pump house Zone 2 - southeast end of the reservoir Zone 3 - service water valve house

' 4.7.13.2 At least once per six months verify that the groundwater flow rate does not exceed the value established in Table 3.7-6. The groundwater flow rate shall be determined by measurements at the drain outlet gallery. A visual inspection of the clarity of the outflow from each drain shall be performed in conjunction with the flow monitoring effort.

NORTH ANNA - UNIT 2 3/4 7-57 Amendment No. 3'),141,

TABLE 3.7-6 SERVICE WATER RESERVOIR - ALLOWABLE GROUNDWATER LEVELS ALLOWABLE GROUNDWATER MEASUREMENT ELEVATION ZONE LOCATION (Mean Sea Level in feet)

1. Service Water Pump House Crest 280

[ Units 1 & 2]

2. Southeast corner of the a. Crest 295 SW Reservoir
b. Toe 280
3. Service Water Valve House Crest 295

[ Units 1 & 2]

SERVICE WATER RESERVOIR - ALLOWABLE DRAIN FLOW RATE DRAIN OUTLETS LOCATION FLOW RATE 1 through 6 Drainage Gallery Total Flow Rates shall not exceed

. 8.5 gallons per minute

' NORTH ANNA - UNIT 2 3/4 7-58 Amendment No. 3'?,76,141,

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i. l Attachment 4 j 4 Significant Hazards Consideration Determination l

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North Anna Power Station Units 1 and 2 Virginia Electric and Power Company w 1

  • 1 SIGNIFICANT HAZARDS DETERMINATION Virginia Electric and Power Company (Virginia Power) requests that specific reference i

to individual groundwater level measuring device numbers identified in TS Surveillance i Requirement 4.7.13.1 be deleted. This revision will avoid redundancy, eliminate l confusion as well as the need to initiate Technical Specifications changes whenever new piezometers are added, older devices are replaced or abandoned in-place.

Additionally, this change requests that Service Water Reservoir (SWR) allowable groundwater levels identified in TS Table 3.7-6, be raised to levels anticipated in the l original Safety Analysis Report and confirmed by a recent engineering calculation.

l Present groundwater threshold levels were noted to be overly restrictive and out-of-date and require Special Reports to be developed whenever threshold levels are exceeded.

Virginia Power has reviewed these changes to North Anna Units 1/2 Technical '

Specifications and has determined that a significant hazard will not result from removing TS reference to SWR piezometer device numbers and increasing the TS allowable groundwater phreatic surface leve! in the southeast section of the SWR. Specifically, l operation of the North Anna Power Station in accordance with the proposed TS Change I Request will not:

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1. Involve a significant increase in the probability or consequences of an accident  !

previously evaluated, since: a) removing non-safety related SWR piezometer device numbers from the TS and raising TS allowable groundwater surface threshold elevation levels in the southeast section of the SWR will have no effect on the way the safety-related Service Water System was designed to operate, b) Periodic Test Procedures will continue to identify all open-tube piezometers and require that they be monitored in order to obtain as much information as possible regarding changing groundwater levels, c) sufficient redundancy will continue to exist since at least two (2) open-tube (standpipe-type) piezometers, not subject to mechanical failure, have been instatied in each of the three (3) SWR zones to meet the TS Surveillance Requirement that "at least one measurement per zone be available" and d) recent calculations have confirmed that raising the allowable water level in the southeast section of the SWR will not affect the stability of the SWR dike as indicated in the original design basis calculation.

2. Create the possibility of a new or different kind of accident from any accident previously evaluated, since: a) the frequency of piezometer monitoring and the intent of monitoring groundwater surface threshold elevations in order to maintain stability of the SWR slope have not changed, b) no physical modification to the plant or new mode of plant operation is involved, c) changes are consistent with the assumptions made in the Safety Analyses and original design basis calculation and d) failure of the SWR dike and ensuing loss of service water was the most serious accident postulated and considered credible. Operation of the SWR is not being changed. Therefore, a new or different kind of accident is note created by the change in groundwater level. In addition, since both the SWR and Lake Anna reservoir provide redundant sources of service water, failure of the SWR is not considered as a credible accident.

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3. Involve a significant reduction in the margin of safety, since: a) increasing the i allowable phreatic surface in the SE section of the SWR dike will not lower the factor l

, of safety with respect to the stability of the SWR as defined by the original design l l basis calculation, b) the margin to failure of the SWR dike has been proven by l calculation to have not been reduced as defined by the original design basis calculation and c) subject changes will not impact the performance of structures, I systems or components relied upon for accident mitigation or any safety analysis assumptions, therefore the margin of safety is not changed by the proposed changed in groundwater level at the SWR.

Based on the above, the proposed changes to the Technical Specifications will not I adversely affect the safe operation of the plant. The changes will not ultimately compromise the stability or function of the SWR.

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