s .

NSDNORTHERN STATES POWER COMPANY

M IN N E A PO U S. MIN N E SOTA 55408

June 19, 1979

Director of Nuclear Reactor RegulationU S Nuclear Regulatory CommissionWashington, DC 20555

PRAIRIE ISLAND NUCLEAR GENERATING PLANTDocket Nos. 50-282 License Nos. DPR-42

50-306 DPR-60

Information on Prairie Island Feedwater Lines

In a letter dated May 25, 1979 from Mr Victor Stello, Director, Divisionof Operating Reactors, USNRC, we were informed of a recent discovery offeedwater line cracking at another f acility and were requested to submitinformation related to the Prairie Island feedwater line design, fabrication,inspection, and operating history for NRC Staff review. This letterprovides a response to Mr Stello's request. The following information isprovided:

Design

1. Provide as-built piping or isometric drawings of the feedwater lineto steam generator sparger within containment. Show details of thedesign such as dimensions, pipe schedule, support type and locations,pipe restraints, and valve (s).

Response

One set of drawings is included as Attachment (A). The drawings inAttachment (A) are current as of the date of this letter. Becausethe drawings are revised from time to time, they should be used withcaution.

2. Provide the results of any stress or fatigue analyses which wasperformed for this system.

Response

The feedwater piping to nozzle weld region has been reanalyzed by thePrairie Island architect-engineer. The results will be forwarded forStaff review when the report is completed. Review of the originalstress analysis indicates it did not reflect the as-builtconfiguration of this region.

2318 318Reanalysis has shown allowable stresses are not exceeded.

7906220357

. .

NORTHERN STATES POWER COMPANY

Director of Nuclear Reactor RegulationPage 2June 19, 1979

Fabrication History

1. Supply a list of the materials for the steam generator sparger, steamgenerator feedwater nozzles, and feedwater piping within containment.

Response

Steam Generator Sparger SA 106 Gr BSteam Generator Feedwater Nozzles SA 508 C1 2Feedwater Nozzle - Feedwaterpiping spool piece * A 106 Gr C

Feedwater Piping ** A 106 Gr B

* Reference Dwg NF 39273-1 and NF 39274-1 (see Attachment A)

** Reference SS-M368 and SS-M327 (see Attachment B)

2. Provide the details of the welding process (co) used to make the nozzle-to-pipe, pipe to sparger and piping welds. Include details of weldingsuch as preheat, joint configuration (include with or without backingring), and post weld treatment, if any.

Response

See Attachment (C). One set of documentation is included.

a. Welding Process - NAVC0 Procedure ITH1-1 Rev. I for FieldWelds in piping and nozzle-to-pipe welds only.

b. Preheat - 200 degress ? minimum (piping velds).

c. Joint Configuration - NAVC0 sketches listed above.

d. Post Weld Heat Treatment - Piping only, per NAVC0 procedureFE-6 plus PWHT Charts. This is typical and also reported oneach Weld Data Sheet for Field Welds. Shop weld fillermetal is quoted in shop weld QA Data Sheets attached toShop Fabrication Drawings. Stress Relief is included in theQC Data Sheets (sign off & Procedure ID).

e. There is no pipe to sparger weld; this is a slip fit.

3. Provide the NDE performed during and af ter fabrication of the weldjoints requested in question 2.

Response

a. visual for fit up 2 ]h j|hb. dye penetrant (final)c. radiograph (final)

. .

NORTHERN STATES POWER COMPANY

Director of Nuclear Reactor RegulationPage 3June 19, 1979

4. Provide the code edition to which the feedwater piping system wasfabricated.

Response

System was fabricated to ANSI B31.1 1967 Edition.

5. State the fracture toughness requirements, if any, for the feedwaterpiping system.

Response

There were no fracture toughness requirements for the feedwater pipingsystem.

Preservice/ Inservice Inspection and Operating llistory

1. State whether the feedwater system welds received a preserviceinspection in accordance with ASME B&PV Code, Section XI.

Response

Unit 1

A preservice examination was performed on circumf erential butt welds onthe feedwater lines from the turbine building wall to the containmentpenetration. Examinations were performed in accordance with 1971 Edition,including the Summer 1971 Addenda, of ASME B&PV Code, of the feedwaterbutt welds in this area, with the exception of three welds on loop Aand two welds on loop B that were inaccessible. A preservice examinationwas not performed on the pipe to steam generator nozzle welds.

Unit 2

Same as Unit 1; except, five welds on loop A and one weld on loop Bwere not examined due to inaccessibility.

2. Provide the extent of inservice inspection performed on the feedwaterpipe to steam generator nozzle welds. Include the results of theexaminations, any corrective actions taken and causes of any failures.

Response

Unit 1

Visual, ultrasonic, and radiographic examinations were performed onthe feedwater pipe to steam generator nozzle welds during a veckendoutage on June 9 and 10,1979. The visual examinations revealed no

2 b

. .

NORTHERN STATES POWER COMPANY

Director of Nuclear Reactor RegulationPage 4June 19, 1979

apparent discontinuities. The only indications detected by ultrasonicexamination were geometric reflectors from the counter bore on loop B.The radiographic examination revealed the same indications as seen onthe construction radiographs, i.e. porosity, with no indications ofcracking in the pipe taper area or around the weld. No corrective actionwas needed or taken.

Unit 2

Inservice examinations have not been performed on the feedwater pipeto steam generator nozzle welds. See the answer to "3".

3. Provide the schedule and extent of inservice inspection for thefeecwater system for the next inspection interval.

Response

The tables in Attachment D indentify the schedule and extent of inserviceexaminations on the feedwater system for the first ten year inspectioninterval. The tables identify the total number of items requiring exami-nation, the amount required during the first ten year interval, the in-spection period that they will be or have been examined, and tho examinationsthat have been completed. For those examinations that have been completed,the weld or hanger number and the year-report number is given in the remarkscolumn.

Unit 1

Du: 'ng the Prairie Island Unit I weekend outage on June 9 and 10, 1979, avisual and ultrasonic examination was pc-formed on the feedwater systempiping welds from the last check valve in both systems to and includingthe pipe to steam generator nozzle welds, with the exception of thechect volve to elbow weld on laop B that was ene.apsulated. In addition, a

radiographic examination was performed on both pipe to steam generatornozzle welds. The auxiliary feedwater piping walds were also examinedfrom the. 'ast check valve to the sweep-o-let connection weld with the

feedwate lines. There were no indications of degradation to these

systems.

Unit 2

For Prairie Island Unit 2, we are planning to examine the feedwater

pipe to steam generator nozzle welds during the next refueling outage.

b J2}

. .

NORTHERN STATES POWER COMPANY

Director of Nuclear Reactor Regulation

Page 5June 19, 1979

4. Provide any history of water hammer or vibration in the feedwater systemanddesign changes and/or actions taken to prevent these occurrences.

Response

See Attachment E.

5. Provide a description of feedwater chemistry controls and a summary ofchemistry data.

Response

See Attachment F.

Please contact us if you have questions related to this information.

Yours very truly,

. -

L 0 Mayer, PEManager of Nuclear Support Services

LOM/DMM/ak

cc: J G Keppler (w/o Attachment A and C)G Charnoff (w/o Attachment A and C)

e'

2318 :22

. .

Attachment A

The following prints are provided for Unit 1:

XH-106-130 Isometric of Unit 1 Feedvater PipingNF-39273-1 Physical Drawing of Unit 1 Feedwater PipingNF-39273-2 Physical Drawing of Unit 1 Feedwater PipingNF-39273-4 Physical Drawing of Unit 1 Feedwater RestraintNF-39273-5 Physical Drawing of Unit 1 Feedwater RestraintNF-39273-8 Physical Drawing of Unit 1 Feedwater RestraintNF-39273-9 Physical Drawing of Unit 1 Feedwater RestraintNF-39273-10 Physical Drawing of Unit 1 Feedwater RestraintNF-39316-2 Physical Drawing of Unit 1 Auxiliary FeedwaterNF-39316-3 Physical Drawing of Unit 1 Auxiliary FeedwaterNF-39326-2 Physical Drawing of Unit 1 Cleaning SystemNF-38422-3 Physical Drawing of Unit 1 Miscellaneous StructuresNF-38422-4 Physical Drawing of Unit 1 Miscellaneous StructuresNF-38422-5 Physical Drawing of Unit I hiscellaneous StructuresNF-38422-6 Physical Drawing of Unit 1 Miscellaneous StructuresNF-38422-7 Physical Drawing of Unit 1 Miscellaneous Structures::r-38422-8 Physical Drawing of Unit 1 Miscellaneous StructuresNF-38422-9 Physical Drawing of Unit 1 Miscellaneous StructuresNF-38422-33 Physical Drawing of Unit 1 Miscellaneous StructuresNF-38425 Physical Drawing of Unit 1 Miscellaneous StructuresXH-106-6104 Through XH-106-6165 Restraint and Hanger Drawings

for Unit 1 Feedwater PipingXH-106-130 Drawing of Anchor ElbowXH-106-131 Drawing of Anchor ElbowXH-80-1 Drawing of Check ValveXH-80-2 Drawing of Check Valve

The following prints are provided for Unit 2:

X-HIAW 1106-246 (NAVC0 A-7047)2318 23-1664 FWH - 53

1665

1667 FWH - 5416681669

3414 FWH - 5834153416

3417 FWH - 5934183419

3421 FWH - 6034223423

A-1

Attachment A (contd.)

X-HIAW 1106-3425 M - 613426342734283429

3430 M - 623431343234333434

3435 M - 633436343734383439

3440 M - 643441344234433444

3445 M - 653446344734483449

3450 M - 66345134523453

3455 M - 67

i'5 2318 .24'

34583459

3460 M - 683461

3462 M - 693463

34643465346734673468 FWH - 70

A-2

.

Attachment A (contd.)

X-HIAW-1106-3469 FWH - 713470347134723473

3555 FWH - 723556

3557 FWH - 733558

3559 FWH - 743560

3561 FWH - 75

X-HIAW-1080-1 Check Valve2

NF 38493-3 2FW - lA2FW - IB2FW - 4BAnch 205

905

NF 38493-8 2FW - 5A Loop A 5 B Supports

NF 38493-9 2FW - 3A4A6A

NF 38493-10 2FW - 2A2B

3B5B6B

SK-1001NF 38492-8 FW RestraintNF 39274-1 Physical }}}

3 FW Restraint Bracket456

7

8

910

A-3

ATTACHMENT B, Std Spec - Hech

t FLUOR PIONEER INC. SS - M 368 (NSP) 1-69Sheet 1 of 2* Rev 6-26-72

STANDARD SPECIFICATIONFOR

PIPING MATERIAL

PRESSURE CLASS: Nominal 1500 psiTCIPERATURE LEXIT: ?!aximum 450'F

FEEDWATER PIPING

Pipe All piping seamless, ASTM A-106 Grade B, per USAS B36.lv, endsbeveled oer PS6C Standard Sketch SK-M474, unless approvedotherwi.e by the ENGINEER. Piping schedule and wall thicknessas described in Piping Design Table SS - M 327.

Pipe Joints 2" nominal and smaller - Socket velded.

2-1/2" nominal and larger - Butt welded.

Welding PS&E Standard Specification :! 400 and M 410.

Fittings2" nominal and smaller - Material ASTM A-131 Grade I or A-105Grade 2, 3000 lb .WCG per USAS I:16.11.

2-1/2" nominal and larger - Material ASTM A-234 Grade WPBor WPBW, w:d 'thickness equal to that of adjoining pipe and conforming to USASB16.9.

Flanges 2" nominal and smaller - !!aterial ASTM A-105 Grade 2, 900 lbraised face socket weld type per USAS B16.5. Manufceturcr'sstandard spiral serrated facing.

2-1/2" nominal and larger - Material AStf A-105 Grade 2, 900 lbraised face veld neck type per USAS B16.5. Manufacturer'sstandard spiral serrated facing.,

GasketsFlexitallic Style CG or equal - Contractor shall furnish conpleteand accurate flange design data to the gasket manuf acturer toinsure that the gasket construction is correct.

BoltingStud-bolt material ASTM A-193 Grade B7 and conforming to USASB16.5.

Nat shall conform to ASDI A-194 Grade 211. Dimensionsshall conform with USAS B18.2.

2318 _26B-1

.

.

SS - M 368 (NSP) 1-69 *

t FLUOR PIONEER INC. Sheet 2 of 2* Rev 6-26-72

Valves

Gate 2-1/2" - 1500 lb per USAS B16.5, body material ASE1 A216Grade WCB, butt weld ends, pressure seal bonnet, OS&Y,Stellite 6 trim.

3" and larger - 900 lb per USAS B16.5, body material AST'lA216 Grade WCB, butt weld ends, pressure seal bonnet, OS5Y,Stellite 6 trim.

Globe-Angle 2" and smaller - 1500 lb per USAS B16.5, body material AST:1A105 Grade 2, socket weld ends , pressure seal bonnet ,OS&Y, Stellite 6 trim.

2-1/2" - 1500 lb per USAS B16.5, body material AST.i A216Grade WCB, butt weld ends, pressure seal bonnet, OSLY,Stellite 6 trim.

3" and larger - 900 lb per USAS B16.5, body material ASI4A216 Grade WCB, butt weld ends, pressure seal bonnet, OS&Y,Stellite 6 trim.

Check 2" and smaller - 1500 lb per USAS B16.5, piston type, bodymaterial AST:1 A105 Grade 2, socket uc1d ends, seal weldedbonnet, Stellite 6 trim.

2-1/2" - 1500 lb per USAS B16.5, piston type, body materialASTM A216 Grade WCB, butt weld ends, seal welded or pressureseal bonnet, Stellite 6 trim.

3" and larger - 900 lb per USAS B16.5, balanced disc type ,body material AST;! A216 Grade WCB, butt wcld ends, pressureseal bonnet, Stellite 6 trim.

2318 ;27.

B-2

P1PlNG D E S I G fi TABLERev. 10-15-71

| QA- DESIGH ASTM STD JOINTPIPING SYSTEM | TYPE FRESS .TEHP SPEC. SPEC. TYPE REHARKS

y PSIG *FFEEDWATERTiow Diagrams :

NF-39222 (Unit 1)NF-39223 (Unit 2)

Piping Drawings vNF-39273-1 6 -2 (Unit 1) $NF-39274-1 6 -2 (Unit 2) I

wm

1. All FU pump disch. piping to first IIA 1500 450 A-106 M-368 BW All piping 8" and larger pm

external restraint up -s tream of Gr. "B" M-400 GTAW to be Sch.100; 6' and' 2containment penetration, excluding, M-410 smaller to be Sch. EO "recire & warm-up lines n

%

2. FW piping f rom firs t external re- IA 1500 450 A-106 M-368 BW All piping 8" and largerT straint to first weld out side Gr. "B" M-400 GTAW to be Sch. 100; 6" and"containment and from first weld M-410 smaller to Sch. 80 exceptinside containment to steam as noted en pipint drawintsgenerators

3. FW piping from first weld outside IA 2250 450 A-106 M-368 BW 16" Sch. 140thru containment penetration to Gr. B M-400 GTAWfirst weld inside M-410 "

me

3LeNN

4-

u-

@xm

* mN -4

00 *

_

$

Attachment C

Index

Units 1& 2 Remarks

1. NAVC0 Ltr 6-11-79 Weld prep end pipe-to-pipea. SK 18580 Rev. 7 Unit I weld prep of spoolsb. SK 20220 Rev. 1 FW-49 and FW-65

Unit 2 weld prep of spoolsc. SK 20268 Rev. 2 FW-67 and FW-46

2. NAVC0 Shop Fab Dwgs Spools - 49 6 65 (Unit 1);with weld histories 67 6 46 (Unit 2);for those spools that Shop welds

connect to the steamgenerators

3. NAVC0 Weld Data Sheets Piping-to-steam generatorFW-164 and FW-216 Unit 1 - Field welds

4. NAVC0 Weld Data Sheets Piping-to-steam generatorFW-177 and FW-133 Unit 2 - Field welds

5. NAVC0 PWHT Charte For Field welds FW-164, 216,

177 and 133

6. NAVC0 PWHT Applies to both Units forProcedure FE-6 Field welds

7. NAVC0 Welding Procedure Applies to both Units for

ITH1-1 rev 1 with PQR Field weldsITH1-I

8. NAVC0 Radiographic Review Documented on envelope;Results for Field welds film and original envelopeFW-216, 164, 177 and 133 retained in vault; copy of

envelope provided.

9. Additional Field Weld Data These are not all, but are aSheets FW-156, 213, 208 and representative cross section161 (Unit 1); FW-170, 169, 131 of pipe-to-pipe / fitting and

and 125 (Unit 2) spool-to-valve welds

10. Excerpt from Project Specifi- Applies to both Units ascation Hiawatha #106 SS-M327 principal requirements.(!!SP) Sheet 6; System DesignTables

11. CMTRs for ASTM A-106 GrC Both Units 1 and 2material used in Spools(pipe only) FW-65, 49, 67 and46

2318 329C-1

.

.

PRAIRIE ISLAND UNIT 1ASYM CLASS ?-Fi<r/4tTsR SY3 TEM Table T

TEN YEAR INTERVAL INSPECTION SU'S!ARY Page I of 2

Sub Cocponent or System and Total 40 Yr. 10 Yr. First IntervalItem Item to be Inspected Items Amt Amt Act & Period Rcrarks

C 2.1 CITUFE3FWTI AL EUT"' WELDSFW-A & 3 MULTIPLE STREAM 3

FEEDWATER A16-FW-13 17 5 1 1 - PER. TiO 4 ELD F4-lh9, RPr NO. 9c-12016-FW-12 4 1 1 1 - PER. THREE

FEEDUATER B16-FW-16 16+ 1 - ---

16-FW-15 5 h 1 1 - PER. ONE WELD FW-220, RPT NO. 77-15.914 WELDS ARE WELD 3 FW-161, FW-162 FW-164*

ENCAPSULATED FW-214, AND FW-216 WEREEXAMINED DURING WEEKEND CUTAG6ON JUNE 9 & 10, 1979. >g~

90 2.1 BRANCH PIPE TO PIPE WELD JOIt.''S FW-A i 3 MULTIPLE STREAMS SFEEDWATER A

16-FW-1'3 1 1 - ---

WELDS FW-16' AND FW-215 We.RSFEEDWATER 3 EXAMINED DURING WEEKEND CLrTAGE

,

16-FW-16 1 0 - --- ON JUNE 4 & 10, 1979.

2 2.5 IVTEGRALLY WELDED SUPPORTS FW-A & 3 MULTIPLE STREAMS

FEEDWATER A'

16-FW-12 1 N/A - ---

16-FW-13 9 N/A 4 2 - P:,3. TW O Q, RPr NO. 79-122,1322 - PER. THREE

N FEEDWATER Ru 14-FW-15 1 V/A 1 1 - PER. ONE K. RPr NO. 97-14

16-FU-14 6* 9/A 1 1 - PE3. TWO-

CD 2 - FER. TMPEE* ENCAFSULATED, EXAMINE TO

VFJTENT FO'3SIELEU

CD

,

IPRAIRIE ISLAND U';IT _ASFE CL ASS ?-FEED'4ATER SYSTEM Table I

TEN YEAR INTERVAL INSPECTION SDB:ARY Page 2 of 2

Sub Component or System and Total 40 Yr. 10 Yr. First IntervalRemarksItem Item to be Inspected Items Amt Amt Amt & Period

C 2.6 SUPPORT COvPO?,?O FW-A&B MULTIPLE STREAMS

FE3 WATER A16-FW-1't 0 N/A 0 ---

FEEDWATER B16-FW-16 2* N/A 1 1 - PER. CNE M RPT NO. 77-62

* ENCAPSULATED

7w

Nu-

s. . .'

-

.

-

PRAIRIE ISLA';D UNIT 1 FSAR AUr.MENTED - FEED 4ATER SYSTEM Table 11

TEN YEAR INTERVAL INSPECTION SL? DIARY Page 1 of 1

Sub Component or System and Total 40 Yr. 10 Yr. First IntervalRemarksItem Item to be Inspected Items Amt Act Act & Period

0 2.1 CIRCUFTERE'?TIAL PUTT WELD 3 FW - A&B F.ULTIPLE STPEAMS

FEEDWATER A16-FW-8 13 N/A 1 1 - PER. TWO WELD FW-124. RP! NO. 78-?,42

2 - PER. THREEFEEDWATER S

16-F'4- 10 "/A ' 1 - PE9 TWO WELD FW-177, RPF NO. 78-44,552 - PER. THREE

FEEDWATER A FW - A&B F.ULTIPLE STREAE316-FW-9 2 N/A - ---

Y 16-FW-11 2 N/A 1 1 - PER. T40 WELD FW-128, RPP NO. 76-8,41"16-FW-12 4 N/A 1 1 - PER. ONE WELD FA-147, RPT NO. 77-24,28

FEEDWATER B16-FW-10 1 N/A 1 1 - PER. THREE16-FW-14 2 N/A - ---

16-FW-15 5 N/A 1 1 - PER. ONE WELD FW-220, RPI NO. 77-15,9

NU-

uuN

.

.

PRAIRIE ISLAND UNIT ASME CLASS ?-FEEDWATER SYSTSM Table III

TEN YEAR INTERVAL INSPECTION SUMMARY Page 1 of 2

Sub Component or System and Total 40 Yr. 10 Yr. First IntervalRetarksItem Item to be Inspected Ite=s Amt Amt Act & Period

0 2.1 CIRCUMFERENTIAL BUTT WELDS FW - A&B MULTIPLs STREAMS

FEEDWATER A16-2FW-13 15 4 1 1 - PER. ONE WELD FW-161, RPT NO. 77-45,5516-2FW-12 2 1 - ---

16-2FW-11 2 1 - ---

FEED'Jr.TER B16-2FW-16 16* 1 - ---

16-2FW-14 4 4 1 1 - PER. ONE WELD FW-116, RPT NO. 77-97,315 WELDS ARE IN ADDITICN, WE ARE PLANNING+

ENCAPSULATED TO ETAMINE THE FEEDWATER PIPSe TO STEAM GENERATOR N0ZZLEj. WELDS DURING THE NEXT REFUELINO

OUTAGE

' ' > , ' PRANCH PIPE TO PIPE WELD JOINTS FW - A&B MULTIPLE STREAM 3

FEEDWATER A

16-2FW-13 1 1 - ---

FEEDWATER B16-2FW-16 1 0 - ---

125 INTeMRALLY WELDED SUPPORTS FW - A&B MULTIPLE STREAh5

FEEDWATER A

16-2FW-13 9 N/A 5 1 - PER. ONE K, RPT NO. 77-10516-2PW-12 0 N /A - 2 - PER. TWO()j 16-2FW-11 1 N/A 1 1- PER. THREE

FEEDWATER B__.

CX3 16-2FW-16 7* "/A 'l 1 - PER. 0:iE C, RPT NO. 77-10416-2FW-1< 0 "/A - 1 - PER. TWO

6 1 - PZR. THREE(>4 * PARTI AL ENCAPSULATION, EXAhlNEle4

TO EXTENT POSSIELE

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2PRAIRIE ISLAND UNIT FSA? AU38';TED - FEEDWATER SYSTEM Table IV

TEN YEAR INTERVAL INSPECTION SCD'ARY Page 1 of 1'

Sub Component or Systec and Total 40 Yr. 10 Yr. First Interval RemarksItes Item to be Inspected Itens Amt Amt Amt & Period

C 2.1 CIMUFERENTI AL PUPr WELD 3 FW - A1B MULTIPLE STREA).S

FEEIT.iATER A16-2FW-8 18 N/A 5 1 - PER ONE WELD FW-151 RPr NO. 77-99,2

1 - PER. TWO UELD FW-148, RPr NO. 78-2,753 - PER. THREE

FEEWATER P16-2FW-8 il N/A 3 1 - PER. TWO WELD FW-105, RPr NO. 78-1,76

2 - PER. THPIE

FEEDWATER A

? 16-2FW-o 5 N/A 2 1 - PER. ONE WELD FW-152, RPr NO. 77-1,9816-2FW-11 2 N/A - 1 - ESP. THREE16-2FW-12 2 N/A - ---

FEEDWATER 316-2FN-10 h N/A 2 1 - PEP. ONE WELD FN-116, RPr NO. 77-C?,316-2FW-15 3 N/A - 1 - PER. THREE

Nu_._.

i.. s

ULn

.

Attachment E

Water Hammer or Vibration History in the Feedwater ,rstem

a) Reference letter dated September 2,1975, f rom L 0 Mayer,NSP, to Dennis L Ziemann, Chief Operating Reactors Branch #2.

b) Reference letter dated January 29, 1976, from L 0 Mayer,NSP, to Victor Stello, Director, Division of Operating Reactors.

c) Reference letter dated December 30, 1977 f rom L 0 Mayer,NSP, to Director of Nuclear Reactor Regulation, U S NuclearRegulatory Commission.

d) On June 8, 1979, while cooling down to perform NDE on Unit I steamgenerator feedwater nozzles, an abnormal operating conditionoccurred allowing the steam generator level to decrease belowthe feedwater ring. It was necessary to lower the steam generatorlevel below the feedwater ring to perform an ef fective NDEon the steam generator nozzle. This was performed before coldshutdown conditions were reached and an apparent secondarysystem fluid flow instability on Loop B occurred. The conditionwas corrected by starting the main feed system and introducingwarmer feedwater to the steam generator.

The feedwater system was inspected for loose hangers, insulation,etc., with no damage noted. The following day, both Loop A andB steam generator nozzleswere inspected as scheduled, utilizingultra sonic testing and radiography. The results of theseexaminations were compared with construction tests with nodegradation of the system revealed.

2318 336

E-1

. .

Attachment F

Feedwater Chemistry - Prairie Island 1 and 2

Prairie Island 1 and 2 are operated using the Westinghouse teedwaterspecifications listed in Table 7-2 of the " Steam Side Water ChemistryControl Specifications Manual" (SIPS-4) provided by Westinghouse.Unit No. I was placed in commercial operation in December, 1973 usingphosphates in the secondary system. The unit was shut down in September,1974, sludge lanced, inspected, and returned to service on AVT chemistry.Unit No. 2 was started up with AVT chemistry in October of 1974.

The feedwater sample taps are located at the inlet to the high pressureheaters and at the final feedwater point just prior to the steam generators.The sample taps are all 19mm connected to a 19mm isolation valve.Immediately af ter the valve the sample line size is reduced to 9.5mm o.d.stainless steel tubing. This tubing continues to the plant's continuouschemistry monitoring instrumentation. Ceeb samples are taken via aparallel sample stream connected upstream of the continuous monitors.

The continuously monitored parameters are hydrazine, specific conductivity,and cation conductivity on the feedwater points. Oxygen is continuouslymonitored at the condensate pump discharge. These process monitors havealarm setpoints and alarm in the chemistry lab and in the control roomand plot on a multi-pen recorder in the control room. These processmonitors are all calibrated on a set frequency by surveillance test.Grab sample analysis for oxygen, iron, and suspended solids are performedon the feedwater points. All wet analysis procedures are traceable toASTM or Standard Methods.

The feedwater is treated with hydrazine injected at the condensatepolisher discharge. The hydrazine pump stroke control manually maintainshydrazine approximately two and one-half times the oxygen level measuredat the condensate pump discharge. Ammonium hydroxide is also added atthe same location for pH control. The ammonium hydroxide pump strokecontrol is automatic, sensing specific conductivity in the feedwater, tokeep feedwater pH at 9.6.

The feedwater chemistry of Prairie Island 1 and 2 has been very consistent.A typical set of values would be:

Cation Conductivity 0.11 umhos (with cond polish 0.08)Specific Conductivity 10.0 umhospH 9.60xygen <5 ppbIron 2 ppbHydrazine 20 ppb

We have maintained a very tight condenser. The plant utilizes fresh waterfor condenser cooling. Under these conditions chlorides have only rarelybeen seen in the steam generators which implies the feedwater is maintainedwith very low chlorides (<.05 ppm).

The feedwater at Prairie Island 1 and 2 has been extensively studied underEPRI RP404-1 by Nuclear Water and Waste Technology. Quarterly progressreports #1 through #14 contain a detailed review of secondary systemchemistqr parameters. }}jg }}

F-1