ML20199E478
| ML20199E478 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 11/13/1997 |
| From: | Kalyanam N NRC (Affiliation Not Assigned) |
| To: | Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| NUDOCS 9711210220 | |
| Download: ML20199E478 (54) | |
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UNITED STATES s
NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2008dHM1
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November 13, 1997 J
Mr.ior. P. O'Hanlon Sen Vice President - Nuclear-Virginia Electric and Power Company 5000 Dominion Blvd.
Glen-Allen, Virginia 23060
SUBJECT:
RESULTS OF DAM SAFETY AUDIT RELATED TO THE CATEGORY I SERVICE WATER RESERV0IR DAM AT THE NORTH ANNA: NORTH ANNA POKR STATION, UNIT NOS.
1 AND 2
,)'-
Dear Mr. O'Hanlon!'
-On February 12, 1997, an ins)ection of the Category I Service Water Reservoir (SWR) Dam was conducted at tie North Anna Power Station.
The NRC staff has received and evaluated the final report related to this audit from its technical assistance contrac+or, the Federal Energy Regulatory Commission (FERC).
The conclusion of the inspection was that there were no conditions observed that would indicate any ininediate concerns regarding the integrity of the dam and associated control facilities. How ver, there were numerous items identified that could lead to safety problems if left uncorrected. The items of most importcnce relate to piezometer readings and movement surveys. Also, important observations were made regarding in-place vegetation below the dam and the condition of the weirs for flow measurements.
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~
Included in the FERC report (Section E in Enclosure 2) is a list of the actions that shall be taken by you to ensure the continued safety of the Cdtegory I SWR dam consistent with the Federal Guidelines for Dam Safety (1979) and the Dam Safety Program Act delined in the Water Resourcts Act of 1996.
It is requested that you provide a written response to these actions within 180 days of receipt of this letter, except as otherwise noted.
As indicated at the time of the inspection. copies of the data sheets provided by NRC to the Federal Emergency Management Agen"y (FEMA) and the Corps of Engineers are included as Enclosure 1 for review, corrections and additions.
It is requested that you review these data sheets and provide the staff any corrections or missing information within 60 days of receipt of this letter.
A copy of the FERC report, dated May 14, 1997, which contains photographs taken of various area thct were inspected during the audit, has been provided as Enclosure 2.
At the time of the audit it was noted by your cognizant personnel that interim data inspections by your staff were due to be performed in calendar year 1998.
e Information from those inspections and evaluations as well as actions you have e
taken relative to the auxiliary dam may be of use in your response to this letter.
t mb ' \\- O \\ ji 9711210220 971113 PDR ADOCK O$000338 G
PDR am 11 ll lll ll'l!OlliII alm FEEpsgsp p m 1
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Ifyobhaveanyquestionregardingtheresponsesandinformationrequested, the report, or schedule for submittal of information, please contact me at (301) 415-1480.
Sincerely, (Original Signed By) s N. Kalyanam. Project Manager Project Directorate 11-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50 338 and 50 339
Enclosures:
1.
National Inventory of Dams & NATDAM Input Fields Definitions 2.
FERC/NRC Operation Inspection Report cc:
See next page
'D'ist ributien
. Docket;Ftle PUBLIC PDII-1 RF B. Boger J. Holonich D. Rom N. Kalyanam E. Dunnington..
s s
R. Haag J. Johnson, RII OGC FILENAME - G:\\NOAt{NA\\SWRDM.CLO OFFICE PM:PDII-10 LA:PDII-L D:RDll-A NAME NKalya N EDunningkon JLyM DATE lb / IF97
// //A/97
// //3/97 COPY Yes/No
/Iei/No LTeh/No v
s v-t k
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I Mr. -J. P. O'Hanlon North-Anna Power Station
-Virginia Electric & Power Company Units 1 and 2-CC:
4 Mr. J. Jeffrey L'unsford'-
County Administrator-Regional Administrator, Region-II Louisa County-U.S. Nuclear Regulatory Commission
~P.O. Box 160 Atlanta Federal Center Louisa, Virginia 23093 61 Forsyth St., SW, Suite 23T85 Atlanta; Georgia 30303 Michael W. Maupin Esquire Hunton and Williams Mr. W. R. Matthews, Manager Riverfront Plaza. East Tower North Anna Power Station 95i E. Byrd Street P. O. Box 402 Richmond, Virginia 23219 Mineral Virginia 23117 Dr.'W. T. Lough Mr. Al Belisle Virginia State Corporation U.S. Nuclear Regulatory Commission Commission Atlanta Federal Center Division of Energy Regulation 61 Forsyth St., SW, Suite 23T85 P. O. Box 1197 Atlanta. Georgia 30303 Richmond. Virginia 23209 Mr. David Christian, Manager Old Dominion Electric Cooperative Surry Power Station 4201 Dominion Blvd.
Virginia Electric and Power Company Glen Allen Virginia 23060 5570 Hog Island Road Surry, Virginia 23883 Mr. J. H. McCarthy, Manager 4
Nuclear !.icensing & Operations Support o
Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Blvd.
Glen Allen Virginia 23060 Office of the Attorney General Cc'imonwealth of Virginia 90b East Main Street
- Riche nd. Virginia 23219
- Senior Resident Inspector North Arna Power Station U.S. Nuc aar Regulatory Commission 1024 Haley CMve Mineral, Virginia bil7 Robert B. Strobe. M.D., M.P.H.
State Health Commissioner Office of the Commissioner Virginia Department of. Health P.O. Box 2448 Richmond.JVirginia 23218 l
--r
=
S PAGE 1/3 10/97 NATDAM INVENTORY OF DAMS INVENTORY DATA NORTH ANNA CAT 1 SERVICE WATER DIKE VA-LOUISA COUNTY DAM INFORMATION NATIONAL INVENTORY F: ELDS ar=======rasm===========================
1.
DAM NAM E................................
NORTH ANNA CAT 1 SERVICE WATER DIKE 2.
OTHER DAM NAMES.................
CAT 1 EMERGENCY COOLING WATER 3.
FEDERAL AGENCY 1D...............
NRCVA1 4.
N ATIONAL 1 D............................
VA83101 5.
LATrfU DE DEG..........................
38 6.
LATITU DE MI N............................
3 7.
LATITU DE S EC...........................
48 8.
LONGITUDE DEG.....................
77 9.
LONGITUDE MI N........................
47 10.
LONGITUDE S EC.......................
13 11.
SECTION, TOWNSHIP, RANGE...
12.
C O U NTY...................................
LOUISA 13, RIVER OR STREAM....................
MINERAL 15.
DISTANCE CITY-TOWN (MILE)...
6 16.
OWN E R NAM E...........................
VIRGINIA POWER CO.
17.
O WN E R TYPE............................
U 18.
NONFED DAM ON FED PROP....
NO 19.
DAM TY P E............................,.....
20.
-- P U R P O S E.................................
O-CAT 1 EMERGENCY COOLING WATER 21.
YEAR COMPLETED....................
22.
DAM LENGTH (ft)........................
7000' 23.
- DAM H EIG HT (ft).........................
35 24 STRUCTURAL HEIGHT (FT).......
25.
HYDRAULIC HEIGHT (FT).........,
26.
MAXIMUM DISCHARGE (CU FT)..
27.
MAXIMUM STORAGE (ACRE FT)..
28.-
' NORMAL STORAGE (ACRE FT)...
BS 9
a m
w.
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DAM NAME: NORTH ANNA CAT 1 SERVICE WATER DIKE INVENTORY DATA
-Y PAGE 2/3 DAM INFORMATION NATIONAL INVENTORY FIELDS -
ESEEEEEEEEEEEEEEEEEEEE=EEEEEEEX=EEEEEEEEE 29.
SURFACE AREA (ACRES)............
8.9 -
30.
DRAINAGE AREA (SQ MILES)......
0.14 i
- 31. -
DOWNSTREAM HAZARD.............
LOW 32.
EMERGENCY ACTION PLAN........
NR 33.
PHASE I INSPECTION..................
NO 34.
INSPECTION DATE.....................
21297 35.
S PILLWAY TYPE..........................
UNCONTROLLED 36.
SPILLWAY WIDTH (FT).................
170 37.
VOLUME OF DAM (CU YARDS).....
38.
NUMBER OF LOCKS......................
0 39.
LENGTH OF LOCKS.,......................
0
- 40. -
WIDTH OF LOCKS (FT).................
0
.-41.
FED AGENCY INV FUNDING...........
NO 42.
FED AGENCY INV DESIGN.............
NO 43.
FED AGENCY INV CONSTPUCTION.
NO 44.
FED AGENCY INV REGULATORY.....
YES 45.
FED AGENCY INV INSPECTION.......
-YES 46.
FED AGENCY INV OPERATION........
NO 47.
FED AGENCY INV OWNER...............
NO 48.
FED AGENCY INV OTHER................
NO 49.
FEDERAL REGULATORY AGENCY.,
USNRC OWNER INFORMATION E================E
E=E=E
1.
OWN E R NAM E.................................
VIRGINIA POWER CO.
2.
O WN E R TY P E.................................... ELECTRIC UTILITY 3-CO NTACT NAM E.................................
4.
CO NTACT TITLE.................................
- 5. -
CONTACT SALUTATION.....................
6.
A D D R E S S 1.........................................
- 7. -
A D DR E S S2..........................................
8.
ADDR E S S3.........................................
9.
CITY.....................................................
10.
STATE.................................................
11.
zip......................................................
12.
PHONE................................................
13.
FAX......................................................
14.
EMERGENCY CONTACT NAME..........
15.
EMERGENCY CONTACT PHONE........
16.
OWN E R N OTE..............................
17.
DATE............................................
s
.. = -
i 1-
- DA,M NAME: NORTH ANNA CAT 1 SERVICE WATER DIKE
. INVENTORY DATA PAGE 3/3 INSPECTION INFORMATION.
333E223E35d333333E223332322CE333333333
- 1. - G EN ERAL CONDITION..........................
Inspection on 2/12/97 by NRC/ FERN noted areas where vegetation must be removed erosion in the groin and the too regions from surface flow to be corrected, regrading for improved drianage to be completed. The -
general conditionof the dam was very good.
The owner has probably completed another -
inspection in 1995 by an independent -
consultant on the five year cycle.
+
s DAM NOTE azzzanassamamecas=ssazzzzzazusammazums
- 1. RESEARCH COMPLETE (Y/N).........
- 2. NOTE................................................
Awaiting additionalinformation from the ovmor.
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l 3.3 THE NATDAM FIELD DEFINITION: FIVE PARTS l
There are forty nine Selds included in the program for the upiate of the National Inventory of Dams. '
l The definition for each field consists of five parts:
A fdf number indicating the order in which the data is to appear in o
the NATDAM database management file.
' The fdf Asbet, indicating the standard name used for each field item.
o For example, Latitude Deg.
~
The feLi type, including alphanumeric. number, or cate.
o The fald aise indicating either a designated size or a variable size o
s with a designated range, which will be supported in the National Innntory of Dams. Fields transmitted with a field size larger than that indicated in the definition, will be truncated ar.d data lost when the file is added to the national inwntory.
I A descripdan of et feld, standardizing the information tranunirted o
for individual data items.
As indicated in the previous discussion of the NATDAM file structure, some flexibility has been provided in field sizes and in the date f wt. In addition, for a few fields, alternative data entrie are supported. If an alternative data entry is provided, it will be desipated within the field item definition.
The alternative data entries will be converted to the standard form by FEMA prior to incorporation into the NationalInventory of Dams.
5 l 4/1/91 I
I
i l
3.4 LIST OF FIELD DEFINITIONS The NATDAM forty nine Geld definitions are as follows. The expression bcluded wkhin parenthesis 4
is used to indicate the type and size of the Seld. For example, the phrase, ' Dam Narne (Alphanumeric, 65 var)' designates an alphanumeric Seld and a variable field size, with a designated range of 1 to 65.
FIELD DEFINITIONS (1) Dam Name (Alpleumerie,65 var)
Ecter the o5cial name of the dam. Do not abbre@e unless the abbreviation is a part of the o5cial name. For dams that do not have an official name, use the popular name.
(2) Other Dam Names (Alphanumeric,65 var)
Enter the reservoir name, followed by (res). Also, if ther,; are names other than the official name of the dam in common use, enter the names in this space. Separate the names using a semi-colon. Leave blank if not applicable.
E (3) Federal Agency ID (Alphanumeric,15 var)
Enter the o5cial agency ide:ttification number for the dam.
I I
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- Note. Field deflaition items #1.M are andar to the first M Tacid items included in the ASDSO National 1m Dams Methodokn State Amenev Manual (10tm Additionalitems were added to the Federaf Arency Manual as a result of the ICODS Subcommittee Meetmg November,1989.
4/1/91 I I
(4) NationalID (Alphanumerie,7)
Enter the official national identitiestion number for the dam. 71Wr ir a mpsedfield md f
naar w = moyfr d ds= hewad h me N nimetL;, ofsame.
'Ite National ID is the Corps identificatlee No. assigned to each dam that was used on the 1981 National Inventory of Dams.
For those dams that were not included on the 1981 National Inventory Of dams, an identification number will need to be generated. Each federal agency will be assigned a range of numbers that may be used to generat,e new NationalID numbers. 74e Y N/Mde M#p d w each h
h
.a.sdwseyewym
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- e no "Ite first two characters of the identity will be the appropriate state two letter abbreviation, based on the location of the dam. The last fiw: (5) characters of the identity will be a urique number l
in the agency's assigned range.
See Tswe 3-2, 1981 National inwntory of Damr. Corps Identification Numbers By Start, for an example listing by state of National ID's used in the 1981 inventory.
Please contact the National Inventory Coordinator for the range of armben assigned to your agency for the generation of NationalID numbers.
I In some cases, it is anticipated that federal agencies will be autring numbers to dams already add:d to the database by another agency. As such cases are identiSed, you will be notified and asked to adjust the National ID number as needed.
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Table 3-2, Lisung by stme, of the last number used as a Corps IdentiQcanon No in the 1981 Nazional Inventory Of Dams.
E
e (5) _ Laetode Dag (Number,2)
(6) Latitude Mir (Number,4 var)
(7) Latitude Sec (Number,2) latitude may be entered in one of two ways. The standard field entry gives latitude in degrees, minutes and seconds. An alternatiu field entry is provided for the conwnience of I
those agencies who track latitet i le degrees, minutes and tenths of a ndnute. If the akernative form is used, FrMA will convest it to the standard form prior to inclusion in the national inventory.
Latitude Standa.1 Entry: Enter latitude in degrees, minutes and seconds, using the three designated fields. For cammple, if the dam is located at 1stitude 38 deg.,52 min.,30 sec.,
enter:
L.atitude Deg: 38 Latitude Min: 52 latitude Sec 30 Ladtude Alternative Entry: Enter the latitude in degrees minutes and tenths of a minute by entering the depost value in Latitude Deg; and the muudar and seiths ofs mhuge value in Latitude Min. Transmit the Latitude Sec Geld as a blank field. For example,if the dam is located at Latitude 38 deg.,52.5 min., enter:
latitude Deg: 38 latitude Min: 52.5 Latitude Sec 4/1/91
(8) tessitude Dag (Number,3)
(9) Lassitude Mia (Numbe,4 var)
(10) Longitude See (Number,2) tonptude many be entered in one of two wavs. If the ahernative form is used, FEMA will 8
convert it to the nadard form pdor to inclusion in the nationalinventory.
Imagitude Standant Entry: Enter longitude in degrees, assutes and seconds, using the three designated Gelds. For example, if the dam is located at longitude 82 deg.,36 min., O sec., enter:
longitude Deg: 82 Longitude Min: 36 Iongitude Sec 0 Loesitude Alternative Entry: Enter the longitude in degrees minutes and tenths of a minute by entering: the derser val'a in Longitude Deg; and the inhuder auf sands of a minute value in Longitude Min. Transmit the Longitude See Seld as a blank Seld. For exampic, if the dam is located at longitude 82 deg.,36.0 min., enter:
Longitude Deg: 82 Longitude Min: 36.0 Longitude Sec (11) Section Township, Range Lacation (Alphanumede,30 var) 11 mis is an optional Seld. If your agency tracks the dam locarian by Section, Township, and Range, please enter the information. Enter the infonnation in any form that is understandable and that clearly designates the individual vaines. For example, S.21, T.3N, R.69W. If the meridian location is needed to locate the dam within the agency, include it in the Seld. For example, S.21, T3N, R.68W of the Sixth Principal Meridian.
u-mm lI
- m
.l (12) Coasty (Alphanumerie,30 var)
Ij Enter the name of the county in which the dam is located.
(13) River or Stream (Alphanumeric,30 vr The 'Jver or Stream designation may be entered in one of two ways. An alternative field entry is pi,wided which is consistent with the ' tributary and offstream* designations used in d
the 1981 National Inventory of Dams. If the alternatin form is used,. FEMA will convert it to the standard form prior to inclusion in f.he national inventory.
I River or Stream Standard Entry: Enter the official name of the river or stream on which.
the dam is built. If the stream is unnamed, identify it as a tributary to a named river, e.g.,
Snake TR If the dam is located offstream
- name of the river or stscam plus *-OS*,
e.g., Snake-OS, River or Stream Altermathe Entry: Enter the official name of the river or stream on which the dam is built. If the stream is unnamed, identify it as a tributary to a named river, e.g.,
TR-Snake. If the dam is located offstream, enter the name of the river or stream plus the word, 'OITSTREAM,' e.g., Snake OFFSTREAN.
1 (14) Nearest City Town (Alphanumeric,30 var)
Enter the name of the nearest downaream city, town, or village that is most likely to be affected by floods resulting from the falure of the dam.
(15) Distance Nearest City Town (Miles) (Number,3 var)
Enter the distance from the dam to the nearest downstream affected City-Town-Vdlage, to the nearest mile.
1 I
4/1/91
- 16
- a E
1 3
4 l
(16)- Owner Nasu (Alphanumeric,50 var)
Enter the name of the owner of the dam.
(17) OwnerType (Alphanumeric,1)
Enter the ande to indicate the type of owner, F for Federal; S for State; L for Lacal Government;
(,
U for Public Utility; or P for Private.
(18) NoaFed Dam On Fed Prop (Alphanumeric,1)
E Enter the code indicating whether this dam is a non-federal dam kwated on federal property, Y for Yes; or N for No.
(19) Dam Type (Alphanumeri% 6 var)
E Enter one or more of the following <* to indicate the type of dam, lg RE for Earth; j
ER for Backen; PG for Gruvity; CB for Bestrees; VA for Arch; MV for Multi Arch; CN for Concrete; Ms foi uncearr.
I l
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l ST for Stooe; TC for Timber Crib; and/or OT for Other.
For example, the entry CNCB would indicate a concrete buttress dam type.
(20) Purposes (Alphanumeric,8 var)
Enter one or mm of Aef" Og codst to indicate the purposes for which the reservoir is used:
I for Irriga lon; H for Hydrwelectric; l
C for Flood Control And Stor n Water Management; N for Navigation; S for Water Supply; R for Recristion; P for Fire Protection, Stock, Or Small Farm Pond; F for Fish And Wildlife Pond; D for Debris Control; g
./ 'Q,," gy.pj T for Tailings; and/or I
O for Ottrr.
The order should indicate the nJaarw decreang kuportance of the purpose. For example, SCR would indicate the primary purposes, Water Supply and Flood ConvolAnd Stoern Water Management, followed by Recreadon.
(21) Year Completed (Number,4)
Enter the year when the original main dam structure was completed.
(22) Dam Emigth (Fee 0 (Number,7 var) l Enter,in feet, the length of the dam, which is defined as: the length along the top of the dam. This also includes the spillway, powerplant, navigation lock, fish pass, etc., where these anm 18 -
1 E
E form pm of e - of ee m. u detached,,om ee - - s_.,es m a.
be included.
E hems 23 25: Dean Height, Hydrusil: Height, structars! Ndsht Ertter a corresponding value for the height Seld(s) that mo. closely correspond to the ' Height of the N hh% used by the agency. If the agency a.rahame matains values for more than one type of height, enter the value for each meresponding height Seld.
De height field (.) thet do not presently co.espond to agency data, may be left blank. This information ihould be added as it becomes available for new dams.
(23) Dam Height (Feet) (Number,6 var)
E Enter, in feet, the height of I.e dam, which is deEned as: the vertical dis.ance between the S
lowest point on the aest of the dam and the lowest point in the original streambed.
(24) Structural Height (reet) (Number,6 var)
E Enter, in feet, the structural height of the dam, which is defined as: the vertical distance from the lowest point of the excavated foundation to the top of the dam.
(25) Hydraulle Height (Fest) (Number,6 var)
Enter, 's feet, the hydraulic height of the dam, which is dehad as: the vertical difference beween the w=um daign water lesel and the lowest point in the original ser---M E
(26) Maxismann Discharp (Ca Ft/See) (Number,7 var)
Enter the number of cubic feet per second (cu ft/sec) which the spillway is capable of discharging when the reservoir is at its maximum designed water surface elevation.
I i
.w.
I
O (27) Mamianum Steenge (Acre-Feet) (Number,10 var)-
Enter, in acre feet, the maximum storage, which is defined as: the total storage space in a
.l reservoir below the n.asimum attainable water surface elevation, including any surcharge l
stora8c.
(28) Norunal Storage (Acre Feet) (Number,10 var)
Enter, in acre-feet, the normal storage, which is defined as: the total storage space in a reservoir below the normal retention level, including dead and inadive storage and excluding any flood control or surcharge storage, I
(29) Surface Area (Acres) (Number,8 var)
Enter, in acres, the surface area of the impoundment at its normal retention level.
(30) Drainage Ana (Square Miles) (Number,10 var)
Enter, in square miles, the drainage area of the dam, which is defined as: the area that drains to a particular point (in this case, the dam) on a river or stream.
8 (31) Downstamm Hazard (Alphanumeric,1)
Enter the code to indicate the potentiM hazard to the downstream area resulting from failure
..is.o,e,adon of e+ o, faeo.
g L for Low,-
S for SigalAcant, or H for High.
E E
E
.m.
R 9
I e
y.
I (32) r-f we Plan (Y/N/NR) (Alphanumeric,2)
Enter the ende, ladicating whether this dam has an Emergency Action Plan (I:AP) which is denned as: a plan of aaion to be taken to reduce the potential for property damage and loss of life in an area affeaed by a dam failure or large flood. Leave blank if unknown.
Enter the code:
YforYes; N for No; or NR for Not Regnired. Enter the code NR if an EAP is not rquired for this dun under the ag acy requirements.
(33) Phase I inspection (Y/N) (Alphanumeric,1)
E Enter the cade indicating whether this dam was inspene.d in the Phase ! Inspection Progran.,
E National Pro
- ram of Inspecion of Non.Feder:3 Dams (P.L 92-367). Leave blank if unknown. Enter the code:
Y fw Ym; N for No.
(34) Imt laspection Date (Date,11 var) gfg b ,ddyf ulo bs/ sperSc' C -aver Ente: the date when the most recent inspection of the dam wa,s performed. Enter the dat
- -sewa:0-
' g in one of the foBowing formats:
- ~"9P N 9
C cwe" avh.
In the form 3UUN87. De month abbreviarians supported by thi 794A database are:
g o
W JAN, FEB, MAR, APR, MAY, JUN, JUI, AUG, SEP, OCT, NOV, Di:C.
o mm/ddhy (06/31/87);
l o
mm/dd/yyyy (06/31/1987); and I.
4/1/91
. 91 l
y 1
.=
yyyymedd (19870631), the form used by Dbase ID Ales.'
j o
If only the superdenyawis known, is.licate the laarwalaa date as the first day of the year.
]
For cansple, inspections perfemned during the year 1988 would be entered in the form O U A N 88.
. If only the '- r' nicaA sidyear are kocma, indicate the inspection date as the first day of the mestk. For example, inspealons conducted la March,1988 would be catered la the form 01 MAR 88.
(35) Spilhsmy Type (Alphanumeric,1 var)
Enter the one letter code that describ s the type of spillway:
C for Controued U for Uncontrolled H for Noas I
(36) Spillway Width (Feet) (Numeric,4 var) 1.
Enter the width of the spillway, to the nearest foot, available for discharge whea the reservoir is -
at hs maximum designed water surface elevation.
j l
(37) Volumne Of Dam (Cubic Yards) (Numeric,12 var)
Eater the total number of cubic yards ocweied by the materials used in the dam nructure.
l
!aelude portions of gewerboose, locks and spillways, only if they are an in'.egral part of the dam i.
and ropind for struaural stabihty.
~
l (38) Number OfImeks (Numeric,1)
I o
Enter the number of existing navigation locks for the project. Maximum of 4, I
I.
i 4/1/91
- 22 -
l 1
c
.._,L_
L..,,
(39) Imagth of14cks (Feet) (Nmmeric,4)
Enter to tbc acarest fcot *.he length of the primary navigation lock.
(40) Edth of Lacks (Feet) (Numeric,3)
Enter to the acarest foot the width of the primary navigation lock.
Items 4148: Federal Agency favolvement Fields E
Eight fields, #41-#48 are provided tu indicate federal agency itivolvement in a dam. At least.ges et the fedev31 laveheesent aside seest be.dsalsnated as T. la order for the dem to be Incinded E
la the Natiemal laventary of Dama.
In fields #41 - #4&, indicate agency involvement with respect to a dam, by entering the mde:
Y for Yes; or N for No.
(41) Fed Agency Ier Fundlag (Y/N) (Alphaaumeric,1)
(42) Fed Agency lav Design (Y/N) (Alphanumeric,1)
(43) Fed Agency lav Construction (Y/N) (Alphanumeric,1)
(44) Fed Agency lav Itegulator- (Y/N) (Alphanmeric,1)
/
(45) Fed Agency lav lastecties.(Y/N) (Alphanumeric,1)
E (46) Fed Agency lav Operation (Y/N) (Alphanu:aetic,1)
E (47) Fed Agency lav Oomer (Y/N) (Alphanumnic,1)
(48) Fed Agency lav Other (Y/N) (Alphanumeric,1)
Anm 23
- E
(49) Federal Agemey Code (Alphanumeric,9)'
Enter the Federal Agemey Code for each dam. TMs is a regelred Seld, and must have se entry for each dean lacleded in the NW leventary of Date ZgdCDI A**'uv Name Federal Amency Code laternational Boundary and Water Comm.
IBWC U.S. Department Of Agriculture Soil Conservatloo Service USDA SCS i
Forest Service USDA FS
]
U.S. Department Of Energy Federal Energy Regulatory Comm.
DOE FERC Tennessee Valley Authority TVA U.S. Department of Interior Fish and Wildlife Service DOIFWS Geological Survey DOIGS Bureau of land Management DOIBLM Bureau of Reclamation DOIBR Bureau ofladian Affairs DOI BIA National Park Service DOI NPS U.S. Department of L. abor Mine Safety and Health Administration DOL MSHA U.S. Departz:nt of Defense l
U.S. Army DOD USA U.S. Navy DOD USN U.S. Air Force DOD USAF U.S. Marine Corps DOD Ui *C j
U.S. Department of Justice Bureau of Prisons DOJ BOP 1
1
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.s OPERATION INSPECTION REPORT for THE NUCLEAR REGULATORY COMMISSION Inspection by WE FEDERAL ENERGY REGULATORY COMMISSION Atlanta Regional Office l
February 12. 1997 Date ofLinspection Dam (name). Service Water Reservoir-Location North Anna power Station Spotsylvania Virginia 1
-(Facility)
(County)
(State)
- NRC Licensed Project North Anna-Nuclear Station Licensee Virginia Power Company (VPC)
Features of the Dam and Impoundment Inspected Embankment. Service Water Pumo House. Service Water Valve House, and immediate vicinities Inspected by John C.
Lyon, Jr.
Accompanied by Mr. Dan Rom (NRC-HO)- Messrs. John S.
Thornton, Jr.
Michael L.
Whalen. and Gary E.
Moclgeleaski (VPC)
Weather Clear. temperature in the low 40s.
pii-rv Based on a review of project. design documents, maintenance and instrumentation records, discussions with NRC representatives and VPC employees, and observations madeiduring the inspection, no conditions were identified that could be considered an immediate threat to the safety and permanence of the project structures.
Observations made
-during the field inspection and review of recent instrumentation data revealed increased. piezometer readings and undefined areas of seepage.
These conditions could poteritially af fect embankment stability and, thus, lead to significant safety problems if not corrected.
A complete list of recommendations is included in the text of the report.
f4 MAY 141997 s'
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Eroimet-Descrintion The: North Anna Nuclear Power Station Service Water Reservoir Dam was constructed in 1973 and 1974 to provide an adequate source of emergency cooling water.for the plant's two - reactors.
The 'sito --is p
- locatedi on _the North _ Anna River-approximately 50 miles (mi) north / northwest of Richmond, Virginia.
The - Service Water Reservoir is a separate feature from the main and cooling reservoirs, with no outlet structure for discharge.
The North Anna River and the South Anna River s
join to form the Pamunkey River, a tributary to the York River.
Normal
~ surface water elevation in the Service Water Reservoir is 310 feet mean sea. level (m.s. l. ) (f t )
Normal surface water elevation in the-main reservoir is approximately 250 ft m.s.l.
Flow from an embankment breach would be diverted into Canal A of the cooling reservoir by an hmergency dike on the northeastern side of the embankment.
The Service Water Reservoir was conscructed by building a dam in an elevated area across two gullies and excavating from the area behind the dam to provide the required volume of emergency cooling water (88 acre-ft), creating a lake of approximately 9 acres.
The watershed for-the Service Water Reservoir is 9 acres.
Approximately 500 feet of the - 3,000-foot perimeter is ' formed by - excavated slopes, with an 11 1
impounding' dam. forming the remaining 2,500 feet.
The dam consists of a wide ~ core of compacted siltv clay, fine and coarse filters, and a 6
wide outside zone of compacted rockfill.
The core is protected on the upstream afde by a 2-foot select earth liner and on the downstream side by transition filters which extend beneath the rockfill.
The overburden beneath the dam and lining was stripped and grubbed or excavated, as required, and the saprolite soil compacted prior to fill W
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- placement.. The--impervious core and lining were founded directly on the compacted surface, which was scarified for bonding..The -material-for-the compacted impervious fill was derived from the upper portion of the.
residual - soil. profile and. was classified silty? clay with a low permeability.
. Bedrock-varies,-but was generally _60-to 80 feet below I
the original ground surface.- The rockfill was obtained from excavation of'slightly' weathered to fresh-hornblende gneiss and granite gneiss in the station area.
The rock was processed and sized to form a durable,
_ dense rockfill with-high shear strength.
The clay liner extende above the maximum pool elevation of 315 feet NVGD, and the upstream slope _is protected by -riprap _ extending below the normal pool.
The rockfill across the crest-is covered w.d th coarse aggregate to form the access road around the perimeter.
There is also a seldom used lower access road along the toe of the southeast,-east, and northeast portions of the dsm. Two massive concrete structures, the Service Water Pump House
.(SWPH) and the Service Water Valve House (SWVH) ere located on the north side of the dam and are integral with the dam. The North Anna Nuclear Station is operated by Virginia Power Company (VPC).
Figure 1 is a location of the North Anna Nuclear Power Station, and figure 2 is a plan view of the dam and major features'.
Figure 3 provides cross-section views of the-dam.
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.e-TABLE 1 Partinent Data Reservoir r
9 a'cres ~ (O'.'14 mi')
Drainage. area
.)
-Normal 1 water surface elevation..
. 310.0 ft NV GD
.. -.... 8.9' acres (0.14 mi#)
Surface area @ el. '10.0.ft-NVGD.
' Volume @ el. 310.0-ft NVGD.
88 acre-ft Maximum storm surcharge 5. 0 f'.
Dam-Compacted =rockfill with impervious core and Type 2-foot lining,-designed for normal and
-seismic loadings.
3.0H:1V=
Upstream slope Downstream slope ~
2.0H:1V Crest elevation 320.0 ft NVGD Maximum height 35 ft Length at. crest 3,000 ft Width at crest 20 ft-Slope protection.
........ Riprap on upstream slopes-Downstream. Hazard Potential..
" Low" NOTE: All elevations are mean sea level.
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R A All4MMENT SETYLEMENT WARKER E
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6-A PIEZOWETEa PLACED WITH FILL DURING EW6ANKMENT CONSTRui ION g
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REFEMiNCE Motel'.tMNT *C* IS LOCATEO EAST OF CANAL *A* AT N3209,EiO971 (PLANT GRt0)
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FIGURE 3-PLAN SERVICE WATER RESERVOIR NORTH ANNA POWER STATION pff h
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DUMPED ROCK SLOPE PROTECTION Mi CREST ELEV. 320 TOP OF CORE ELEV. 318
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l FIGURE 3 TYPICAL SECTION OF DIKE SERV CE WATER RESERVOIR NW.IH ANNA POWER STATION
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A.
SAfaty_Qf the_ Project.
1.
Dame, Dikes. _andlppurteDant Structurna.
The inspection team walked the crest and the downstream toe of the Service Water Reservoir (SWR) dam, the abutments, and accessible areas of the Service Water Pump House and Valve House (SWPH and SWVH).
No conditions were 1
observed that might be considered an immediate threat to the safety and permanence of the project structures; however, conditions that might continually affect the dam stability were discovered.
VPC staff divided the SWR into six areas for ease of reporting (see Figure 2).
a.
Serlice._ Water _Reamrvoir Dam.
The upstream slope of the SWR dam is protected by dumped rockfill riprap that extends from the crest to the base of the liner (Photograph 1).
No indications of movement o.
the upstream slope such as
- sliding, sloughing, or subsidence were observed.
The crest and roadway along the top of the dam appeared to be in good condition, with no indicatic.no of
- cracking, sliding, or subsidence. Several areas in the crest access road have been cepaired where minor erosion of the crest occurred, and these are regularly repaired by station personnel (Photograph 1).
The downstream slope appeared to be in good condition (Photographs 16 and 19).
The slope is protected by riprap which was observed to be i
fresh and angular with good interlock.
Some indications of movement and/or subsidence of the riprap were observed near the juncture of the
- riprap, the coarse
- filter, and the toe of the downstream slope (Photograph 14).
These areas appear to be the result of 20 years service (Photographs 16 and 17).
In area 4 (southeast portion of the SWR), the stumps of previous vegetation were observed. VPC staf f stated
r.
8 that this clearing was a result of the last inservice inspection (ISI) performed by VPC in 1994.
Wet spots (Photographr. 14 and 17) were observed along the embankment side of the lower access road in areas 3 and 4 (east and southeast portions of the SWR).
Snowmelt could be the cause of the wet spot along the _ lower access road in _ area 3, as the observed area w0s at t
the road edge and extended downgrade from the high point of the road surface. However, the wet spot along the embankment side of the lower
}
access road in area 4 (Photograph 17) appears to be result of seepage.
In the immediate vicinity of this spot, there were no additional signs of moisture either at the toe of the embankment or along the original ground.
Visual observation did not indicate a low spot-in the road grade for runotf collection.
The inspection continued into the southeast area where, approximately 400 feet downslope, an isolated wet spot was found on the bank above a very small creek.
These wet locations, considered with increasing piezometer readings (see section A.2), indicate significant changes in the embankment behavior, which could directly af fer:t the stability and permanence of the dam.
Weir boxes, previously installed along the downstream toe toward the small creek side to measure scepage, have been abandoned and are now r
overgrown with vegetation, b.
Servism_.Wat.ar_ P"=p HQue..and Valte House.
The SWPH and SWVH, both massive concrete structures, are integral with the dam.
Four 36-inch-diameter service waterlines pass through the north wall of the SWPH without penetrating the clay liner.
There is also a 12-inch-2 diameter fire line and electrical conduit that pass through the top of the SWPH. Two 32M-inch-diameter service waterlines tie into the north t
wall of the 5%VH and are wrapped with clay liner material. Observations 9
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indicate no problem areas with regard to e'..&. rat. on from the embankmett, offsets, cracking, or other forms of 6 tress.
The SWPli, when originally constructed, 4 c. ope to const rable
/
,... ci remedial
/
settleme:t which resulted in extensiv av s;.
- 4. m 1 l
measures. Horizontal drains were insta* h 9 w % Ora's '.
3, ground water at elevation 275.0 f t or below, Drain outf u. : s monitored in a gallery northeas: of the SWPil.
Adjacent to the SWPit, a protective cover for the buried water l
service lines was constructed, which is essentially a three-sided box.
From observations, there has been some relative movement between the northeast corner of the SWPH and the southeast corner of this protective cover.
The inspection did not indicate recent movement. VPC staff pr:vided settlement readings for the SWPil and the SWVli to the NRC on March 12, 1997, and this information was later provided to ARO staff for review. Based on a review of the data from the last 5 years of settlement readings, any relar.ive movement between the protective cover and the torcheast corner of the SWPl{ occurred prior to 1991.
c.
Emergencylike and Dt.tsh.
In consideration of a potentia'.
embankment
- breach, an emergency dike and ditch were construe:ed to deflect the flow away from the nuclear station and into the coohng water reservoir.
observations indicated that adequate grass cover had been established.
No areas of erosion, sloughing, or settlement were noted.
i d.
Reservoir.
The reservoir shoreline was inspected from the
- dam, and no stdications of active shoreline erosion or accumulations of floating trash or debris were observed.
2.
Inatrumentation.
Project instrumentation includes surf ace monuments, piezometers, inclinometers, horizontal drains (under the
-10 SWPH) and weirs.
Each instrument has a threshold value which triggers a VPC investigation and reporting process to the NRC to -determine the cause for the deviation and to propose corrective measures.
a.
surface Monuments.
Monuments are located along the crest of the dam to monitor horizontal and vertical movement.
Horizontal measurements were discontinued in 1989.
Photograph 10 shows a typical location of a survey reference point along the protective cover adjacent to the SWPH. There is an extensive monument measuring system for the SWPH and SWVH with very precise threshold values.
Vertical survey readings submitted by VPC to the NRC on March 12, 1997, indicate a maximum cumulative settlement of 0.29" at one location 1
(southwest corner of the SWPM). Other locations of the SWPH and SWVH ranged f rom 0.10" to 0.20" settlement over the last 5 years, b.
Phaemeters.
Piezometers are located along the crest of the dam, near the SWPH, SWVH, and downstream of the toe.
According to reviewed documentation, the original purpose of the piezometers was to determine reservoir seepage.
Tip elevations extend well below the clay liner and below the original ground-water elevation. Piezomoters are read on a quarterly basis.
During the construction phase, pneumatic piezometers were installed in the crest, downstream sicpe, and tou of the embankment.
A considerable number were installed around the SWPH, including one piezometer with an inclined casing placing the piezometer tip directly below the SWPH.
Twenty plus years later, only two of the ' original. pneumatic piezometers are still functioning.
Piezometeds were replaced in 1990 and again in 1993 with open standpipes.
Currently, there are eight functioning piezometers.
Recently, one piezomuter, P-22, exceeded the maximum (threshold) value forsthat location.
Thio crest piezometer is located in area 4
-(southeast portion) near the maximum embankment height.
Discussions
l 1
o 11 with VPC staff: indicate that values are approaching the assumed l
I phreatic surface assumed in the etability calculations.
Readings above the level assumed in the calculations would indicate decreased factors of safety.
In addition, almost all piezometer readings show an upward trend over the last 12 to 24 months. VPC staff prepared a December 10, l
l-1996, report to the NRC discussing the behavior of P-22 which, at that l
time, was the on1'y pienometer above t.he maximum allowable elevation-eccording to the technical specifications.
Since that report, P-10 has almost reached the threshold value established for that location.
Another piezometer, P-21, continues to show an increasing water elevation.
P-10 is located just beyond the toe of the embankment and I
between P-21 and P-22. Summary plots of readings from the last two years of piezometers P-10, P-21 and P-22 and other piezometers are included as attchments. Based on the overall review of piezometers, increasing reading frequency, and installing additional piezometer are l
appropriate.
Recommendations concerning the piezometers are listed in section E.
Prior to the installation of horizontal drains under the SWPH, three vertical test wells were drilled adjacent to the SWPH, then later abandoned.
The casings have been maintained, and these could be used af ter cleaning to obtain water level readings near the SWPH and support piezometers P-11, P-14 (new), and P-20.
c.
Inclinometers.
Three inclinometers are installed at the SWR, Two are located adjacent to the SWPH, and one, SI-3, is located at the toe of: area 4.
No. readings have been made within the last 10 years.
It is strongly recommended that, if a reading can be obtained from SI-3 that, it be done, d.
5911montal Dra ha.
Flow from each horizontal drain is measured at the gallery.
In VPC's' latest ISI report, the flow from all
12 drains is less than 2 gpm, although specific readings were not provided.
The maximum allowable flow according to the technical specifications is 8.5 gpm.
From information provided during the inspection, VPC personnel monitor the water chemistry and amount of sediment in the drain collection area. It is recommended that the flow i
I measurements of the horizontal drains be performed quarterly and results summarized in the annual instrumentation report.
e.
Mairs.
Previously, thero were 4 weirs and a weir wall in the drainage feature south of area 4.
These have not been read, and some are apparently inoperable.
The inability to quantify seepage from the embankment in view of the increasing piezometer readings and the i
observed wet spots constitutes a significant information loss to determine the present and future behavior of the SWR.
Clearing of the downstream area, reestablishment of the weirs, and periodic readings should be implemented.
3.
Downstream Mazard Potential. Classification.
Since the SWR dam is located above the cooling reservoir, f ailure of the SWR dam would result in an increase of the cooling reservoir elevation via Canal A.
The increase is not considered significant enough to upgrade the downstream hazard potential classification.
The SWR dam is therefore classified as a " Low" hazard potential dam.
No conditions were observed during this inspection that would warrant a change of classification.
4.
Consul. tant's safety Inspection Report.
Independent-con-sultant's inspections were made by Stone
& Webster Engineering Company.
The most recent 5-year independent consultant's inspection was made in July 1990.
The consultant found the project to be in good
yt condition.
No problems affecting the safety, of the project were i
reported.
5.
Licenmaa's Inapaction Proar.u.
The following table summarizes the liceAsee's inspection program for the SWR:
Inspection Frequency Performed By Last Inspection Visual Quarterly VPC-NAPS Piemmeters Quarterly VPC-NAPS Monuments Quarterly
- Bengston, Elkin, ltd.
3 DeBell, &
Operation / Safety S-Year VPC-DES 06/21/94 4
NAPS - North Ann Power Station DES
- Design Engineering and Support The inspection schedule appears to be appropriate for the project size and complexity.
3.
Operation and Maintenance.
The project appeared to be effi-ciently operated and adequately maintained, with the exception of some problems in the drainage feature below area 4.
1.
Da==.
Dikas, and Annurtsnant structures.
The upstream riprap appeared to be in good condition.
The riprap appeared to be f ree of vegetative growth.
Downstream slopes are protected by riprap.
There was evidence of some recently cut vegetative growth in the riprap near area 4.
The natural ground slopes away from the toe of the dam, following the original topography which included two gullies.
South of area 4, tihe area -is overgrown to render flow measurement impractical.
Clearing and cleaning of the bank and channel of the small creek and-reestablishment of weirs should be accomplished as indicated in section E. Findings and Follow Up Action.
i 1
--e, 1--
,,a
o 2.
Spillway _ Cates and Standby __P._ownr.
Not applicable; there is no spinway r.asociated with the SWR.
3.
Enwer Plants.
There is no hydro plant at this site.
The pond is used to provide emergency cooling water for the nuclear power plant.
4.
Enserv.nir.
The reservoir appeared to be clean and f ree of debris.
No indications of erosion were observed.
Operation and maintenance of the reservoir appear to be in accordance with good engineering practice.
5.
Ennor.da.
Design / construction /as-built drawings and operation records are maintained by Vpc at the site and at the corporate offices in Richmond, Virginia. Design / construction records are also maintained at the NRC-HQ offices in Washington, D.C.
6.
Emergencyl ction Plan.
Since the SWR dam is classified as a " Low" hazard potential dam, no emergency action plan is required, c.
Enrironmental. Public_Us e,_.. and_S a f e ty.
No environmental, public use, or safety problems were noted during the inspection.
The dam and reservoir are closed to the public.
The area is fenced and access road gates are locked.
Existing public safety devices appear adequate and are properly maintained.
No additional actions to protect life and property were required as a resul*, of the inspection.
D.
Matters of CDmmingion Intercat.
1.
Rddi.tlons. Detterments. Le.ases. Pntirsment s.
or Neede.d Extchaiona.
Not Applicable.
2.
Requiring _Comminnion_Ac_ tion.
Not Applicable.
3.
Project.Complianen.
Not Applicable.
r 4
15 E.
FinM aan
==d rollowun m ia==.
The inspection team observed no conditions that might adversely af fect' the immediate safety of the projects.however, several conditions were observed that could lead to safety probl, ems if left uncorrected. The importance of gathering additional 'information is crucial to understanding the current and future performance of the SWR embankhtent, and whether remedial measures -
will be required to ensure the integrity of the SWR.
We recommend an aggressive increase in instrument monitoring frequency, installation of some additional instrumentation, and significant clearing of vegetation i
- from drainage areas downstream of the embankment.
The following recommandations have been categorized as actions to be taken immediately (within 30 days),
short term (within 90 days),
and intermediate (within = 120 days).
1.
Immediate Action (within 30 days):
Increase piezometer reading frequency from quarterly to a.
-monthly, b.
Using embankment survey monuments, perform a horizontal movement survey and compare with the previous re& dings.
Piezometers P-21 and P-22 should be read, bailed until the c.
water level-is 5 to 10 feet below the current level, and then read periodically during refilling to determine if
-the piezometern are operative and if the current readings are correct, d.
Inclinometer-SI-3, located at the toe of area 4, should be read and results. compared to the latest' available reading, 2.
-Short Term-(within 90 days):
ae clear the vicinity around the weir wall of vegetation and obstructions ~to enable flow measurements, f
a, e-e y
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e 16-b.
In the area between the weir wall and the access road, clear vegetation and maintain cleared for visual observation. Note any wet spots and develop a recording procedure to identify -the locations and-monitor the extent.
L c.
At the culvert that passes under the lower access road j
(dividing line between zone 3 and 4), clear the: upstream i
and downstream sides of vegetation.
d.
Reactivate weirs for flow measurements. Those that cannot be made functional should be removed and new weirs estab1,ished.
VPC staff indicated that analysis of seepage water could e.
determine whether seepage was from the SWR, Once the weirs are operational, water samples should be taken to see if the water source is in fact the SWR.
f.
Prepare and submit for approval additional piezometer installation locations in arean 3 and 4 and in the downstream vicinity.
i g.
Review stability calculations based on the latest piezometer readings.
h.
P-10, a pneumatic piezometer, should be carefully purged I'
s and reread.
3.
Intermediate (within 120 days) :
a.
Determine if the test wells can:be used to obtain water
' level' measurements for comparison with P-11, P-14 (new),
and P-20.
p b.
Install an additional settlement marker in the east
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c.
Reevaluate embankment-stability based on the latest piezometer readings and survey.results.
3 d.
Continue tree / brush removal.
e.- Conduct quarterly flow measurements for the horizontal l
drains that extend beneath the SWPH and include a summary I
of readings in the annual instrumentation ' report.
i f
f.-
Prepare a-report for review documenting additional.
i measures to be taken based on instrumentation data and r
predicted performance of the embankment.
FERC staff conduct followup inspection a d project review.
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Upstream slope of SWR, area 6 at left foreground i
and west end of area 1 at upper right.
Dark spots (arrow) are pothole repairs completed prior to the inspection.
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Northeast corner of SWPH. Note vertical offset nt left corner cf photograph.
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Note overgrown culvert and meist spot at toe.
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Photograph 15 02/"2/97 Opposite side of lower access road from previous photograph. Nc.e overgrown condition near culvert.
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rap.
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West downe'. ream slope of area 4.
Ncte the vegetation
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Photograph 21 02/32/97 Weir wall below the lower access road. Marshy conditions and drainage channel should be cleared to enable flow measurements.
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