ML20217N877

From kanterella
Jump to navigation Jump to search
Rev 0 to SIR-98-011, Evaluation of Damage Mechanisms for Svc Water Sys at ANO-2
ML20217N877
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 03/27/1998
From: Giannuzzi A, Licina G, Sauby M
STRUCTURAL INTEGRITY ASSOCIATES, INC.
To:
Shared Package
ML20217N838 List:
References
SIR-98-011, SIR-98-011-R00, SIR-98-11, SIR-98-11-R, NUDOCS 9804090238
Download: ML20217N877 (29)
v • d • e


Text

, .

1 Report No.: SIR-98-011 Revision No.: 0 Project No.: EPRI-110Q File No.: EPRI-110Q-401 February 1998 Evaluation of Damage Mechanisms for the Service Water System at Arkansas Nuclear One Unit 2 i

Prepasedfor:

, Entergy Operations s

Prepared by:

StructuralIntegrity Associates,Inc.

San Jose, California l

Prepared by: - Date: ) f 2-) 95 M. E'. 'auby 0 e flA

~ '

Date: 3-21 A D 0$ L'ina Reviewed by: Date:_ Y $

/#

[. J. Giannuzzi Y Date: 3l* 7 TV A. F. Deardorff Approved by: Date: 1l*'lf V N. G. Cofie 980409023e 980331 h StructuralIntegrityAssociates,Inc.

PDR ADOCK 0500036e G PDR

-. }

/

A REVISION CONTROL SHEET Document Number: SIR-98-011

Title:

Evaluation of Damage Mechanisms for the Service Water System at Arkansas Nuclear One Unit 2 Client: Entergy Operations SI Project Number: EPRI-l10Q Section Pages Revision Date Comments All All 0 03/24/98 InitialIssue I

L h StructuralIntegrity Associates, Inc.

I 1'

l l

i l

Table of Contents t.

v Section Eage 1.0 INTRO D U CTION .. . . . . . . . . . . .. . . . .... . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. .. .. .. . . . . . . . . .. . . . 1 - 1 1.1 Background......................................................................................................................1-1 1.2 Sy stem Description.... ........ .... ..... .... ... ......... .. .. .... .. .. . .......... .. ...... . . . ... ..... ...... ........ ... . . ........ . 1 - 1 1.3 Scope.................................................................................................................................1-2 2.0INPUTDATA.....................................................................................................................2-1 l-l1 2.1 Pressu re and Temperature ...... . ...... . ..... ....... ...... . ...... .... ... ... .. ......... .. .... ....... .. .. . . .... . .... ... . 2- 1 l 2.2 Fl o w Co n di ti o n s . . . . . . . . . . . . . . . . .. .. . . . . . .. .. . . . . . . . . . . .. . . . . . .. . . . . . .. .. . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3 Wate r Che mi stry.. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . .. . .. .. . . .. . . . .. . . . . .. . . . . . . . . . . . .. 2 -2 2.4 B iocide Treatment .. ..... .... ... . ...... .... .. .... .... . .. ......... ............ . .... . ......... ... ... .......... .... . ..... .. . .. .. . 2-3 2.5 Materials.......................................................................................................................2-4 1

3.0 IDENTIFICATION OF DEGRADATION MECH ANISMS...... . ............... ................ ...... 3-1 3.1 Thermal Fati gue (TF) . .. . .. . ... .. ..... ....... ......... . ... . .... ... .... .. .... .. . ..... . . .......... ...... ...... ....... .. . . .. 3 - 1 3.2 S tress Corrosion Cracking (SCC) ...... ......................... .......................... ............ ............. 3-2 l ] 3.3 Localized Corrosion (LC) ..... ... ....... ..... -. ..... . ...... .. ......... . .. . ....... .. ................ ... .... . . . .. . . ... . 3-4 3.4 Fl ow S ensitive (FS ) ................. ... ..... .... . . . . ... ... ...... ...... ..... ..... .... .... ... ....... .. ..... .. .. ....... . ... .... 3-5 3.5 Vibration Fati gue......... . . ....... ..... . ..... . . .. . .... . .......... ....... .... . ............... . . .... ............ ... .. . . .. ... 3-6 3.6 Wa te r H amme r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . ... . . . . . . . . . . . . . . . . . . .. .. . . . . . . . . .

4.0 S UMM AR Y AND CONCLUS ION . .. ..... ..... . . .. ... . . . .. . ... ... . ..... . . . ....... ..... ......... .. . ... .. . ........ . .. .. . 4- 1

5. ............................................................9......................................................

l t

l l

l l

l V

1 SIR-98-011 Rev. 0 lii f StructuralIntegrityAssociates,Inc.

List of Tables Table Page a

Table 2-1 Service Water System Design and Operating Temperatures and Pressures........... 2-5 Table 2-2 Service Water System Flow Conditions In Large Diameter Pipe .......................... 2-7 Table 2-3 Service Water System Non-Header Piping Flows.................................................. 2-9 i Table 3-1 Degradation Mechanism Criteria and Susceptible Regions................................... 3-9 Table 4-1 D amage G rou ps .. . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . .. . .. .. .. .. ... . . . . . . . . . . .. .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4- 1 I

I l

i

()

SIR-98-011 Rev. 0 iv f StructuralIntegrityAssociates,Inc.

[

~

Ot/

1.0 INTRODUCTION

1.1 Background

The Electric Power Research Institute (EPRI) has developed an alternate approach for the inservice inspection of piping systems in lieu of the requirements currently specified in Section XI of the ASME Boiler and Pressure Vessel Code. The EPRI approach is based on the application of a risk-informed process which :onsists of the following two essential elements.

  • A consequence evaluation is performed to assess the impact on plant safety in the event of a piping failure.
  • A degradation mechanism evaluation is performed to assess the failure potential of the piping system under consideration.

,- The results from these two independent evaluations are coupled to determine the risk significance

) of piping segments within the system.

The purpose of this report is to document the degradation mechanism evaluation for the Service Water System (SWS) at ANO-2 utilizing the EPRI Risk Informed Inservice Inspection Evaluation Procedure (RISI) of Reference 1 in a pilot plant application study. The consequence evaluation for the ANO-2 SWS has been performed separately in Reference 2.

1.2 ' System Description l

I The SWS, in conjunction with the Auxiliary Cooling Water System (ACWS), serves the following purposes:

  • Provides cooling water for Nuclear Steam Supply System (NSSS) auxiliary equipment during j normal operations.
  • Provides cooling water for secondary auxiliary equipment during normal operations.

l

(

SIR-98-011, Rev. 0 1-1 { StructuralIntegrityAssociates,Inc.

. Oe Provides cooling water for NSSS auxiliary equipment during engineered safeguards (ES) operations, e- Serves as an altemate (emergency) water supply for the Emergency Feedwater Pump.

e' Serves as an altemate (emergency) supply to the Spent Fuel Pool.

l l~

o The system consists of two independent flow paths, designated loop I and Loop II, which fumish water to two independent 100% capacity Engineered Safeguard Features (ESF) equipment trains -

and two non-Seismic Category I flow paths (Auxiliary Cooling Water and Component Cooling Water Heat Exchangers).

Water for the SWS is normally supplied from the Dardanel.le Reservoir through intake bays located in the Intake Structure. Three SW pumps are pmvided to supply the various components cooled by the SWS.

O V The Emergency Cooling Pond (ECP) serves as a back-up source of water to the SWE. Water is supplied from the pond by gravity flow through a single 42 inch diameter line to the SWS pump compartments in the Intake Structure. Water from the ECP is circulated though the SWS and is then retumed to the ECP via a 30 inch diameter retum line.

l Although the water entering the SWS receives some biocide treatment, it is essendally raw water.

Many parts of the SWS are in the standby mode and are primarily stagnant or experience continuous low flow. Other parts of the system are subject to intermittent flow primarily during system tests. The boundaries of the SWS are defined in Reference 2. ,

i 1.3 Scope 1

A complete description of the piping included in the evaluation of the ANO-2 SWS is provided in Reference 2. A summary of the piping lines included in the evaluation is provided in Section

2. As a result of the consequence evaluation performed in Reference 2, some non-ASME Code class piping lines are included in the scope of this evaluation.

I j

SIR-98-011, Rev. O I-2 Structorsllatogrity Associates, Inc.

t

2.0 INPUT DATA In order to perform the degradation mechanism evaluation for the ANO-2 SWS, some basic plant data is required. This section provides the input data used for the evaluation. The operating conditions to be considered for a nuclear plant service water system are far different than those for most other systems in nuclear plants. The operating status of the service water system is

. almost completely , independent of the operating condition of the plant in contrast to systems such as the reactor coolant system or power conversion system.

2.1 Pressure and Temperature l

j The design condi'. ions vary throughout the SWS but do not exceed 150 psig and 220 F as shown 1 I

in Table 2-1. The operating temperature rarely exceeds 120 F and experiences a much different

! aqueous environment than most other systems. For example, untreated raw water (from the lake or emergency pond) flows through the service water system. The chemistry of those waters can vary over time and seasonal variations are common. The service water system at ANO draws l water from a shallow lake that experiences definite variations in t :mperature and water chemistry as described in Section 2.3. This environmental variability is dramatically different from the 4

carefully controlled-purity-water used in other plant systems.

l l 2.2 Flow Conditions l

l ~

i l The service water system consists of two loops. In summer, under normal operation, approximately 7,000 gpm flows through one SWS loop and about 10,000 to 12,000 gpm flows t

through the other loop. On the average, the Loop 1 room coolers (small coolers) take about 250-300 gpm, spent fuel cooling takes about 2,000-3,000 gpm, and component cooling takes about 5,000-6,000 gpm. Portions of the service water system may be subject to continuous flow, to nearly continuous wet lay-up, or to a daily, weekly, monthly, or quarterly cycling operation.

A SIR-98-011, Rev. 0 2-1 h StructuralIntegrityAssociates,Inc.

1 P

Even though both loops are in almost continuous operation, there are segments that are usually i stagnant based on References 3 through 6. The normal 110w conditions of the SWS segments are summarized in Tables 2-2 and 2-3. It should be noted that, for completeness, Table 2-3 includes other small diameter piping (less than 4 inch NPS) supply and return lines to various components (e.g. control room emergency condensers) that are not listed in Tables 2-1 and 2-2. However, these lines have been eliminated from further considerations based on the fact that they are i bounded by the analysis of piping greater than 4 inch NPS as documented in Reference 2.

2.3 Water Chemistry The ANO service water system is a once-through system fed from Lake Dardanelle and other fresh water tie-ins. Spring rains cause the lake water chemistry to fluctuate the most and late Summer is usually when water chemistry is the worst. The lake turns over approximately twice  !

per year.  !

b v

Ranges of water chemistry (low /high):

pH 7.5/9.0 Conductivity 100/500 pS/cm Sodium 15/120 ppm l Total Alkalinity 75/250 ppm Total Phosphate .2/2.0 ppm Total Hardness 75/200 ppm Chloride 10/100 ppm (Peak at 300 ppm)

Sulfate 10/50 ppm TSS 50/150 ppm (highest in Spring)

Iron .2/<1 ppm Copper 0.1/0.2 ppm O

LJ SIR-98-0l 1, Rev. 0 2-2 h Structors!IntegrityAssociates,Inc.

1 i

l l

l '

y-(,) 2.4 Blocide Treatment Originally, the SWS was untreated. In 1981, treatment with gaseous chlorine (typically several times per day) was initiated to control macrofouling. The chlorine gas system was installed late 1

in stanup and operated essentially continuously through approximately 1990. It was effective for macrofouling.

Currently, the normal biocide treatment at ANO-2 is sodium hypochlorite. The measured biocide content is 0.2 to 0.3 ppm (total residual oxidant) at the discharge of the CCW heat exchanger.

Sodium hypochlorite plus sodium bromide is also used. Note that the SWS also provides makeup for the circulating water system. Circulating water cycles 2 to 4 times. ANO-2 has been using i l

sodium hypochlorite continuously for the past 7% years, except for a short period in 1992. In 1992, the continuous addition of biocide was discontinued. However, continuous treatment was restarted as a result of biological fouling of shutdown cooling heat exchanger 2E-35A. In j j

<3 addition to the hypochlorite, ANO-2 has also used sodium bromide for six years, orthophosphate (vl i plus zine plus polymer (at 0.1 to 0.3 ppm Zn) for three years, and is now using a synthetic l

polymer as a dispersant. Coupons have been monitored for more than seven years and a  ;

biological station (BioBox) was installed about four years ago.

I ANO-2 observed some high corrosion rates, due to the continuous use of the gaseous chlorine system. ANO-2 has observed an averaga. corrosion rate of ~5 mpy on carbon steel (Corraters with corrosion coupons for back-up) and 0.10 mpy on 90-10 copper-nickel. The use of sodium hypochlorite has been beneficial and has eliminated approximately 99% of the biological fouling.

System performance has improved and many small coolers which used to foul do not exhibit fouling any longer. Slime was observed in the system through 1993 but is not observed currently.

Biocide plus inhibitor is projected to manage corrosion in the ANO-2 SWS through end-of-life.

p Y

l 31R-98-011, Rev. 0 2-3 f StraturalintegrityAssociates,Inc.

1 3- . 2.5 Materials The majority of the pressure boundaries in the service water system are constructed from carbon steel. Austenitic stainless steel is also used for some piping and components. Most valve and i

pump bodies and heat exchanger shells are materials of similar composition and properties to those of the piping. Heat exchanger tubing is typically fabricated from copper based alloys. Pump -

and valve internals include copper alloys, stainless steels (austenitic, martensitic, and precipitation hardening grades), hard surfaces, and non-metallics. Only the piping pressure

- boundary materials (i.e., carbon steel and stainless steel) have been considered in this evaluation.

.l O

l l

l O  ;

5IR-98-011, Rev. 0 2-4 { StructuralIntegrity Associates, Inc.

~

Table 2-1 y Service Water System Design arid Operating Temperetures and Pressures Component Component Description Design Operating Press Temp Press Temp psig(l) 'F (l) psig(l) 'F (l) 2HBB-2 Penetration Pipe Between 2HBC-68 and 2HBC-103, Class 2 150 120 70 72 2HBB-3 Penetration Pipe Between 2HBC-69 and 2HBC-104, Class 2 150 120 70 72 2HBB-4 Penetration Pipe Between 2HBC-77 and 2HBC-105, Class 2 (4) 150 210 55 172 2HBB-5 Penetration Pipe Between 2HBC-18 and 2HBC-106, Class 2 (4) 150 210 55 172 2HBC-32 Service Water Pump Discharge - Lines From Three Separate Pumps 152 120 110 72 2HBC-33 Service Water Supply Header #1 150 120 110 72 2HBC-34 Service Water Supply Header #2 145 120 110 72 2HBC-35 Service Water Supply Header #1 to Shutdown Cooling HX 2E-35A 150 120 76 72 2HBC-43 Service Water Supply Header #2 to Shutdown Cooling HX 2E-35B 150 120 70 72 2HBC-50 Service Water Return Header #1 150 180 67 82 l 2HBC-51 r Se'vice Water Return Header #2 150 180 67 82 2HBC-59 SW Return from Shutdown Cooling HX 2E-35A to Header #1 150 175 67 82 l kHBC-60 SW Return from Sin;-Jo.vri Cooling HX 2E-35B to Header #2 150 175 65 82 1 l

2HBC-63 SW to Emerg Diesel Gen hcket Coolant Water HX 2E-20A 150 120 72 72 l 2HBC-64 SW to Emerg Diesel Gen Jacket Coolant Water HX 2E-20B 150 120 72 72 2HBC-68 SW from Supply Header #1 to Penetration Pipe 2HBB 2 150 120 60 72 2HBC-69 SW from Supply Header #2 to Penetration Pipe 2HBB-3 150 120 60 72  ;

2HBC-75 SW Return from Emerg Diesel Gen Jacket Coolant Water HX 2E-20A 150 140 57 82 l 2HBC-76 SW Return from Emerg Diesel Gen Jacket Coolant Water HX 2E-20B 150 140 57 82 2HBC-77 SW from Penet Pipe 2HBB-4 to Return Header #1 150 210 45 82 2HBC-78 SW from Penet Pipe 2HBB-5 to Return Header #2 145 210 45 82 l 2HBC-81 SW from Valves 2SW-44A and 2SW-44B to SW Return Headers I and 2 152 140 50 82 2HBC-83 Service Water Return to Emergency Pond 158 180 30 82 2HbC-81 Emer FW Pump 2P7B Suction from Service Water Header #1 150 130 89 60 2HBC-86 Emer FW Pump 2P7A Suction from Service Water Header #2 150 130 89 60 2HBC-87 SW from Supply Header #1 to Valve 2CV-1525-1 (Fuel Pool HX) 150 130 87 72 2HBC-87 SW from Supply Header #2 to Valve 2CV-1526-2 (Fuel Pool HX) 150 130 87 72 2HBC-88 SW from Emer Pond Discharge to Intake Structure 10 130 10 60 O

S1R-98-011, Rev. 0 2-5 StructuralIntegrity Associates, Inc.

(m Table 2-1 (Cont'd) d Service Water System Design and Operating Temperatures and Pressures Component Component Description Design Operating Press Temp Press Temp Psig(l) *F (l) psig(l) 'F (l) 2HBC-103 SW from Penet Pipe 2HBB-2 to Cont SW Cing Coils 2VCC2A and 2B 150 150 40 105 2HBC-104 SW from Penet Pipe 2HBB-3 to Cont SW Cing Coils 2VCC2C and 2D 150 150 40 105 1

2HBC-105 SW Remrn from Cont SW Cing Coils 2VCC2A & 2B to Penet Pipe 2HBB-4 150 220 40 105 l 2HBC-106 SW Return from Cont SW Cing Coils 2VCC2C & 2D to Penet Pipe 2HBB-5 150 220 40 105 2HBD-23 SW & ACW Downstream of Valve 2CV-1540 to Cooling Tower Basin 150 100 30 85 2HBD-23 SW & ACW Lines to SW Return Headers I and 2 150 100 30 85 2HBD-26 SW and ACW Return to Reservoir 150 105 30 85 2HBD-33 Supply Line from CCW to HX 2E-28A, B & C 150 120 73 72 2HBD-35 Return Line from HX 2E-28A, B & C to SW Headers 1 & 2 150 130 60 84 2HCC-33 Service Water Supply Header #1 at Flow Meter 2FE-1401 (2) 150 120 110 72 2HCC-34 Service Water Supply Header #2 at Flow Meter 2FE-1402 (2) 150 120 110 72 l

2HCC-294 Retum From 2E-35A (3) 150 175 65 82 zHCC 295 Return From 2E-35B (3) 150 175 65 82 Return from Aux Cooling Water System to SW Return Headers #1 and #2 150 130 80 90 j

{BD-618 i

I Notes: 1. Operational parameters from line list [7).

2. Descriptions and conditions for 2HCC-33 and 2HCC-34 based upon the 2HBC-33 and 2HBC-34 descriptions and P&ID M2210.
3. Description and conditions for 2HCC-294 based upon the 2HCC-295 description and P&ID M2210.
4. Design and operating temperatures based upon faulted conditions when the containment cooling coils are iequired.

SIR-98-011, Rev. 0 2-6 f StructuralIntegrityAssociates,Inc.

'l l l 1 . 1 Table 2-2 Service Water System Flow Conditions In Large Diameter Pipe l

Component Component Description Material PrincipalFlow Condition (l) l 2HBB 2 Penetration Pipe Between 2HBC-68 and 2HBC-103, Class 2 Carbon Steel Stagnant l 2HBB-3 Penetration Pipe Between 2HBC-69 and 2HBC 104, Class 2 Carbon Steel Stagnant 2HBB-4 Penetration Pipe Between 2HBC-77 and 2HBC-105, Class 2 Carbo i Steel Stagnant 2HBB-5 Penetration Pipe Between 2HBC-78 and 2HBC-106, Class 2 Carbon Steel Stagnant j 2HBC 32 Service Water Pump Discharge Lines From Three Separate Pumps Carbon Steel Continuous 2HBC-33 Service Water Supply Header #1 Carbon Steel Continuous 2HBC-34 Service Water Supply Header #2 Carbon Steel Continuous 2HBC-35 Service Water Supply Header #1 to Shutdown Cooling HX 2E-35A Carbon Steel Low / Stagnant (2) 2HBC-43 Service Water Supply Header #2 to Shutdown Cooling HX 2E-35B Carbon Steel Low / Stagnant (2) 2HBC-50 Service Water Return Header #1 Carbon Steel Continuous 2HBC-51 Service Water Return Header #2 Carbon Steel Continuous 2HBC-59 SW Return from Shutdown Cooling HX 2E-35A to Header #1 Carbon Steel Low / Stagnant (3) 2HBC-60 SW Return from Shutdown Cooling HX 2E-35B to Header #2 Carbon Steel Low / Stagnant (3) 4BC-63 SW to Emerg Diesel Gen Jacket Coolant Water HX 2E-20A Carbon Steel Stagnant 2HBC-64 SW to Emerg Diesel Gen Jacket Coolant Water HX 2E-20B Carbon Steel Stagnant 2HBC-68 SW from Supply Header #1 to Penetration Pipe 2HBB-2 Carbon Steel Stagnant 2HBC-69 SW from Supply Header #2 to Penetration Pipe 2HBB 3 Carbon Steel Stagnant  !

2HBC 75 SW Retum from Emerg Diesel Gen Jacket Coolant Water HX 2E-20A Carbon Steel Low / Stagnant (3) 2HBC-76 SW Return from Emerg Diesel Gen Jacket Coolant Water HX 2E-20B Carbon Steel Low / Stagnant (3) 2HBC-77 SW from Penet Pipe 2HBB-4 to Return Header #1 Carbon Steel Stagnant 2HBC-78 SW from Penet Pipe 2HBB 5 to Return Header #2 Carbon Steel Stagnant i 1

2HBC-81 SW from Valves 2SW-44A and 2SW-44B to SW Return Headers 1 and 2 Carbon Steel Continuous 2HBC 83 Service Water Return to Emergency Pond Carbon Steel Stagnant 2HBC-85 Emer FW Pump 2P7B Suction from Service Water Header #1 Carbon Steel Stagnant 2HBC-86 Emer FW Pump 2P7A Suction from Service Water Header #2 Carbon Steel Stagnant 2HBC-87 SW from Supply Header #1 to Valve 2CV 1525-1 (Fuel Pool HX) Carbon Steel Continuous 2HBC 87 SW from Supply Header #2 to Valve 2CV-1526-2 (Fuel Pool HX) Carbon Steel Stagnant 2HBC SW from Emer Pond Discharge to Intake Structure Carbon Steel Stagnant O

SIR-98-011, Rev. 0 2-7 h StructurniIntegrity Associates, Inc.

l Table 2-2 (Cont'd)

O Service Water System Flow Conditions In Large Diameter Pipe Component Component Description Material Principal Flow Condition (1) 2HBC 103 SW from Penet Pipe 2HBB-2 to Cont SW Cing Coils 2VCC2A and 2B Carbon Steel Stagnant 2HBC-104 SW froin Penet Pipe 2HBB-3 to Cont SW Clr.g Coils 2VCC2C and 2D Carbon Steel Stagnant 2HBC-105 SW Return from Cont SW Cing Coils 2VCC2A & 2B to 2HBB-4 Carbon Steel Stagnant 2HBC 106 SW Return from Cont SW Cing Coils 2VCC2C & 2D to 2HBB-5 Carbon Steel Stagnant

~

2HBD-23 SW & ACW Downstream of Valve 2CV-1540 to Cooling Tower Basin Carbon Steel Stagnant l

2HBD-23 SW & ACW Lines to SW Return Headers I and 2 Carbon Steel Continuous 2HBD-26 SW and ACW Return to Reservoir Carbon Steel Continuous 2HBD-33 Supply Line from CCW to HX 2E-28A, B & C Carbon Steel Continuous 2HBD-35 Return Line from HX 2E-28A, B & C to SW Headers 1 & 2 Carbon Steel Continuous l 2HCC-33 Service Water Supply Header #1 at Flow Meter 2FE-1401 (3) Stainless Steel Continuous 2HCC-34 Service Water Supply Header #2 at Flow Meter 2FE-1402 (3) Stainless Steel Continuous 2HCC-294 Return From 2E-35A Stainless Steel Stagnant

?HCC-295 Return From 2E-35B Stainless Steel Stagnant 1BD-618 Return from Aux Cooling Water System to SW Return Headers #1 and #2 Carbon Steel Continuous Notes: 1. Flow conditions based upon normal position of control valves as shown on P& ids

[3-6].

2.. During normal operation a segment of each of these lines supplies water to small (1% to 4" diameter) lines and a segment of each of these lines is stagnant.

3. During normal operation a segment of each of these lines is stagnant and a segment of each of these lines receives water from small (1% to 4" diameter) lines.

1 O

SIR-98-011, Rev. 0 2-8 h StructuralIntegrityAssociates,Inc.

l 1

e r

er e r g u u a i n

3O

(

d e

c o h2 o d

e c

d e

c o h2 h2 h2 h2 h2 h2 m

u s h2 r 2

r h2 d2 0r o 0. P r t

n o

0r

0. Pr P r

r t

o 0r e n 0. p 2 t 0re n 0. p 2 o

t 0h n 0. nt o

t 0 n0 o

t 0 n0 o

t n

o 0a

0. s s

n 0e t

p1 o t 0h n 0. nt o

m11 pe m11 pe e p m1 1 r

et m1 1 r

et m1 om1 m1 1 m1 1 m1 h 1 t o 0. tht s m1 m11 om 2 t n tr n 1 ni r 83 1 2t h 83 1 2t h ht d 83 r ae 83 a e 83 r 83 83 83 no 83 oe 83 r

_ 1 2 um 1 7 r eqeum 1 2 e 1 2 1 2 1 2 1 2mm 1 2 e e er on r r n nn r h m e e r o oa ereqe r e r e r e r e e r r ? h puret n e r er e r e er le _

pum pum pupepp ent o e m1 pur ep lp pur lp ep o pu pu pu r 3 r pu _

le e

eder ic c et 1

eder2 c c et r et s edepu ic c edepu c

ceS ed y c er ice ed ic ec ed ic ec edf ic e cto n ed c ee u iccS ed y ic r D

r u wopn t

r e iwopn t

r e pn e e woes r 9

iwoc r Pn9

. wov r e wo r wor wou r oio won r Pr n0 o6

. wFixe t

v e

n Pecm n Pecm cm t n

P w2 t

n o2 t

n r c P e t

n P t n

P t n

P ea t t n n r e oer ne ne w r ne oen0 r oen0 r oep r oep r r oepont ro oeo0 oeic 6 ioe t p olp it p olp olp it po4 it po4 ioei t ovr it it it it pi it pv l

a np a np np a a a a a a t 6 r er a0 F

i et a0 r et a0 1 i

r ee r e r e r e cep a a r r e ou r e ou ou r r ee dulciSya t ulciS d ya , t iS t

a dulcr1yu2 ulcr dyu2 ul s dync ul c d y dulc y dulcim yv u ul cu1 d yd2 ul cs d yn ecr6u ecr6u r u7 ecd e ecd e eci ec ec ec epr ecet re eci t

ugd 3 t ugd 3 d 00 t ugeru t ugeru t ugin t t ug t ug ugs g t t uguu t ugi nn t

nir0 l n

u4 in nlir0 u4 r

u4 i

niu nt n J.

niud nt ne i niu n ni n nn i nilnnn i i i nnnd li niu _

ime u ho0 me u o0 mei l l imeic meh l

imeu l

imeu l

imehrg memc i e i meh l .

5f ho0 um x 5f umor uc u ca u 5f e5r o uc 5f e 1 r1 2 1

1 r 1 2eh 1 1 2 1 5f 1 r1 P e i 1 r1 Pe 5f a e 5f e 5f e 5f 1 rEe c ah 5f es 1 rE 1 r 1 r 1 r1 P 1 rE

+ e = +

  • e + + = = + + e + . e + *
  • s w w 8 2 2 0 0 0 l

o M t

6 4 79 99 25 32 23 22 09 32 4

9 9

9 605 778 0 9 99 9 8 F

g T s

e 1 1 1

i n

p i w P M r t 09 605 e a 0 0 00 00 00 32 0 0 778 00 99 d m a r o

e N 3H n s fb do e 1 1 1- 2 22 22 1 1 22 1- 52 21 1 1 9-ka - 1-1 N - - - - - - - -

3 4 96 67 89 24 1 9 03 01 2 92 31 2 a V 0 0 00 88 88 66 1 1 1 1 000 23 66 Tme t ie n

o 5

1 V

5 1

V 55 1 1 VV 44 1-1 VV 44 1 1 VV 55 1 1 VV 55 1 1 VV 55 1 1 VV 555 1 1 1 VVV 55 1 1 VV 55 1 1 VV s on C C CC CC CC CC CC CC CCC CC CC y o 2 2 22 22 22 22 22 22 222 22 22 S I s

r e

t a e 7 1 9 5 5 6 1 02 654 34 5 6 9 7 6 5 6 04 7 05 8 555 558 68 W w 7 7- 2- -9 2 2 2 1 7 1 7- 222 222 22 CBB C -

C C - - - - B - - - - - -

e n r

u B B CC C C C C B CB C B CCC CCC CCC CC CC c t H H C H C C C BH H BH H CCC i

e 2 2 H 2 H H H H2 2 H2 2 HHH HHH HH v

r R 2 2 2 2 2 2 222 222 22 e

S y m la cs c

ner s m o

m o

o o

ir t

r e

l a le el o o R r e clo s go R R m s a rs le o t t t t n e r o r r n n n o EC ie eC a a e e e o wle le o is Dr e Dr s e mt e g

e g m m m R d o gm n _

  • p yl co yl c o Ein h h p n n p eo eC i

o n iu ia s ia d o c

s no eC n eC o mU og c

it c

it q t nil t ls ni m

u F ym l

iRu _

D e g r r gr on w w E oo oo P c o Bt n _

eo r o et Ri s S E la C Cg CC g nsr no ye _

mtar mar n 2 rs s ics 2g eR r am lo tr d e 1 r e r r 1 n

pl in ige g p i E e E e pl a pl t le pl i r r li ip o a lo em oo o oo o co oo o oo

  • n
  • n nn x uqu Ae
  • G Be

n A8 CD A8 AB CD ACB AL AB e AAA B8B AB 22 22 00 22 22 777 66 99 0 n 034 O34 1 1 - - 22 - - - - - - - - 1 1 o

p 266 266 EE

- - CC CC CC CC CC CCC CC CC v EEE EEE VV UU UU UU CC CC UUU UU UU e m VV VV VV VV VV VVV VV VV o 222 222 22 222 22 R C 22 22 22 22 22 22 1

e 68 8 0 4 3 4 657 398 32 1

3 4 99 5 6 6 8 20 9 30 444 844 86 0-W 6 -

6- 22 - -

2 2- 2~

6 B 6 - 1

- B -

222 222 -

22 - - 8 C C C BC C BC 4p CC C C C B HB B HB CCC CCC CC 9-

' p a

B H

2 B

H 2

CC HH C

H C

H C

H H 2H 2 H 2H 2

CCC HHH CCC HHH CC HH R 22 2 2 2 2 2 222 222 22 I S S

$EqCk  :

g ENbmw8ky &9 _

l

l s - _

r 0id u

OV r e

t a

t r

e a

r e

t a

r e

t a

r e

t a h2hoy t 0 8 t a o4m 5 r

r e

t a

r e) t aR t r

e) aR W W W W W o n 0. f pd o f e sur W WAS WAS e

ic e

ic e

c e

ic e

ic m1 o y1u5 1 h d e ic ht s e cm e cm v

r v r iv r

v r v r

83 1 2 uis mlla (

e t

n e2 c v n iv ro io v r e e e e e mt n c o od r e o rf rf m

S r

S r

S r

S r

S r

r er ein w puit one ivr mrPa n S m e

Se u e

Se u kt e e e e e 8 r1 r 8 rl v v e ed mod e ea rl ea e v v v pt s 1 e v 1 vv vv r e n

e n

e n

e n

e ic eca u n y ps t e y e e D

u e e e e n e wo r eesh i y emn r

vp e n

e r

e nw eo nw eo h h h h h t Pcg n r iv al d ls egm h v e hf l hl w w e w e w e w e w e oer t o peu u e w w(e w (e f

so c lo wic o e0l e e F wic wic wic wic it a u c5 p n5 pu wic c n wic wic lov f r lov r lov r lovr lovr r e n g er )s ul cinh e n o lovr o lov lovr e f e f e f e f e it r ss ss u n ss ss ss dyri t g n o d>S f ss e d e

f ss e f e

s un oi oi un oi u n oi un oi ecle le o a ugoudt t c et .

hs a02 un h u n =

=_n nncrofae n uo u u u u oi s oi u s p i nm e nme nm nme nm ih e lu es0 nm u lu u nm =m r

it nt s it nt ie t

nt s it nt ie t

nt s mehh sl e u ccyc ln i

f e

t u5 it e f e

ie t it e ni3n0 oy oys oy oys oy nt s nt s nt s 5f eaaay l l oy n oy oy Cs C s. Cs Cs Cs 1 rE edc A Lim 2 Cs L i

Cs Cs

+ . . e * = * * = . e +

  • s w w o t 5 o

l F 820 898 32 8 0 74 6 8 4 7 7 A 9 5 A A A l t 555 545 65 1 23 7 5 / / / /

F s 4 5 1 1 1 N 1 N N N e

g T i

n p w i

P F lo r 820 898 0 00 32 8 0 74 4 7 l

) e a 555 545 65 1 23 C 0 1 1 7

1 OO 9 5 O 7 5

00 55 dd m 1

't a r 1 22 o

n e N oH J o-n s s s e e e s s e 0 w v v 1- 2 1- -2 1- -2 1 2- e v

21 e v 1 1 - -

v 1 ObN - -

l a la la 78 56 78 3 6 1 6 la 56 01 -

V 00 44 44 5 3 la la 2 V V V 1 1 V V 22 33 e m n l 44 44 44 4 4 77 l 55 55 e o a la 1 1 1 1 1 1

1 l

a 00 l a a 1 1 1 1 l

b t it u u VV VV VV V V u VV u u - - - -

a y s a n n CC CC CC C C n CC n n VV VV lo a a a a a CC CC TS i s M M 22 22 22 2 2 M 22 M M 22 22 r

e t

a e 6 7 1 2 1 0 98 4 0 5 22 n 7 7 33 44 33 9 9 90 1 5 5- 2 6 9 49 67 i

W L n

2- 2- 22 - -

22 - -

22 - -

C 2 22

- - A 22

- - A 8- 3-B CC B C e r C C CC CC CC CC /

CC / C D u C C CC CC CC N N B B c t H H HH HH HH H C H C CC CC H H e 2 H 2 H HH HH i

v r R 2 2 22 22 22 2 2 22 22 2 2 e

S t u r s s r p e tal e r t r

e U m t a

n t a

al r u e r e o eo eo m e P e g o t t W n Ho HoC o t a y H s t

a r p a g o n C n o g r dy u e n R W a n le w e H it p wm oo wm oo p l a S r

p h o o d en H k a lo lo ors li i

e o oe r

c d o tu R d o tu R m

u S t o C eo Fi t

n Mo P P o Cg n

s P n C s p t e e h re r p e nre yc yl t a D h Sg e cu d s cnue le e r nh e

wg n c I

Sg S m m m u nS icr ug n 2 na Ps r us nsr on e ce eF F n x 1

a He P r ia le dt a P g s p Az y gt t a oE p

ph ph I le r r n uch nh t I oc oc

  • lo So no S em ts la on e mp e ec mt a LE ox LE ox Co

" C P o LC oo CC h x SE P

H mu EP PA ES px SE oe CH t

n ABC DEF AB le e 1 1 AB AB A B AD8ECF u A8C

=

r o

1 1 1 I 1 1

- - - 1 1 22 77 5 5 333333 AB 67 Fl o

7 888 0 p CCC CCC CC 55 44 3 3 555555 77- -

88- -

t o 2- 222 .

UUU UUU UU EE EE E

E EEEEEE PP EE nP E - - -

EEE v

m o VVV VVV VV 22 22 2 2 222222 22 22 e p 2 222 e C 222 222 22 S R ,

1 e 8 9 1 2 47 36 05 1 n 7 7 77 33 33 5 3 65 78 29 7 3 0-i L 3 4- 93 88 66 08 2- 2- 22 22 22 - 22 - - 22 31 8- 3-y C

C C - -

CC - - - -

C D 8 lp C CC CC CC B B CC CC CC 9-

][v S p

u C

H 2

C 2

H CC HH 22 CC HH 22 CC HH 22 H

2 H

2 CC HH 22 BB HH 22 CC HH 22 CB HH 22 B

H 2

B H

2 R I

S k p g Q:::Em:n - byo -E&s  ;

o &9

(h

() 3.0 IDENTIFICATION OF DEGRADATION MECHANISMS The EPRI RISI procedure of Reference 1 identifies several mechanisms that must be evaluated.

These mechanisms and evaluation criteria are shown in Table 3-1. Of all the mechanisms identified in Table 3-1, only segments susceptible to flow accelerated corrosion (FAC) are classified in Reference 1 as resulting in a "large break". Segments susceptible to any other mechanisms are classified as "small leak". A discussion of these mechanisms as they relate to the service water system at ANO-2 is provided in the following paragraphs using the input data presented in Section 2.0.

3.1 Thermal Fatigue (TF)

Thermal fatigue is a mechanism caused by altemating stresses due to thermal cycling of a component which results in accumulated fatigue usage and can lead to crack initiation and p

J growth. Due to the cyclic nature of thermal transients, only those transients which occur during the initiating events Categories I and II as described in Reference 1 are considered in the evaluation of j degradation mechanisms due to thermal fatigue. Category I consists of those events which occur during routine operation, e.g., startup, shutdown, standby, refueling, etc. Category II consists of i those events which have anticipated operational occurrence, e.g., reactor trip, turbine trip, loss of  ;

main feedwater. Therefore, the transients to be evaluated are those transients which occur under I J

normal operating and upset conditions.  ;

3.1.1 Thermal Stratification, Cycling, and Striping (TASCS)

TASCS is thermal fatigue related to local stratified flow conditions or other cyclic conditions (e.g., due to valve leakage or fluid mixing). This system is not subject to TASCS. The low operating temperature and the resulting minimal AT (less than 50 F) of the service water piping does not provide sufficiently large thermal strains that can lead to thermal fatigue as a result of TASCS.

A 5IR-98-011, Rev. 0 3-1 { StructuralIntegrityAssociates,Inc.

1 r

l p 3.1.2 Thermal Transients (TT)

Fatigue due to thermal transients occurs in systems that experience significant changes in fluid temperature conditions during their normal operation. Piping segments having operating j temperatures greater than 270*F for austenitic steel piping and greater than 220 F for carbon steel I piping should be evaluated for the iatential for degradation from thermal transients. Maximum l operating temperatures of the SWS are 82*F for stainless steel and 172'F for carbon steel piping as discussed in Section 4.0. This system is therefore not subject to thermal transients.

l 3.2 . Stress Corrosion Cracking (SCC)

The electrochemical reaction caused by a corrosive or oxygenated environment within a piping system can lead to cracking when combined with other factors such as a susceptible material, temperature, and stress. This mechanism has several forms with varying attributes including intergranular stress corrosion cracking, transgranular stress corrosion cracking, external chloride stress corrosion cracking, and primary water stress corrosion cracking.

3.2.1 Intergranular Stress Corrosion Cracking (IGSCC)

IGSCC results from the combination of sensitized materials (caused by a depletion of chromium in regions adjacent to the grain boundaries in weld heat-affected zones), high stress (residual welding stresses) and a corrosive environment (high level of oxygen or other contaminants).

Most of the SWS is fabricated from carbon steel which is not susceptible to IGSCC. A small portion of the SWS (e.g., return lines from Shutdown Cooling (SDC) HXs 2E-35A and 2E-35B)

' is fabricated from stainless steel. Even though this system operates at a temperature of less than 200'F, the system water contains an initiating comaminant (10 to 100 ppm of chloride), and as such, this portion is potentially susceptible to IGSCC.

l IGSCC has not, however, ever been observed to exist in the SWS at ANO-2. Prior inspections

and repairs of this system have not revealed the presence of any degradation attributable to SIR-98-011, Rev. 0 3-2 f StructuralIntegrityAssociates,Inc.

l l

l l

n IGSCC. Furthermore, from an overall industry standpoint,' IGSCC has not historically been a I U source of degradation in SW systems.

l l Censequently, although the system conditions fail to definitively preclude IGSCC in the stainless steel portion, the potential is considered extremely low on the basis of lack of ANO-2 or industry historical evidence. Therefore, this mechanism is not considered active for the SWS.

1 3.2.2 Transgranular Stress Corrosion Cracking (TGSCC) l l Austenitic stainless steel base metal and welds in water containing chlorides, or other halides, at temperatures greater than 150 F, and in the presence of a tensile stress may form stress corrosion cracks that propagate with a transgranular morphology. TGSCC is not considered to be present in l the SWS since the normal operating temperature is less than 150F.

1 1

3.2.3 External Chloride Stress Corrosion Cracking (ECSCC)

ANO-2 complies with the requirements of Regulatory Guide 1.36 for non-metallic thermal I insulation and consequently the potential for ECSCC to occur does not exist.

3.2.4 Primary Water Stress Corrosion Cracking (PWSCC)

PWSCC occurs when high temperature primary water is the corrosive medium and is present in l

combination with a susceptible material and high tensile stress. Piping attachments are considered susceptible when fabricated from mill annealed Alloy 600 that is cold worked, or cold worked and welded without stress relief. l i

PWSCC is not applicable as a potential degradation mechanism for the SWS. As indicated in Section 2, all piping in this system is either carbon steel or austenitic stainless steel, and there is no Inconel (Alloy 600) present in the system.

l

' SIR-98-011, Rev. 0 3-3 h StructuralIntegrityAssociates,Inc.

l

i i

I l

3.3 Localized Corrosion (LC)

In addition to SCC, other phenomena can produce localized degradation in piping components.

These phenomena typically require oxygen or oxidizing environments and are often associated j with low flow or " hideout" regions, such as exist beneath corrosion products or in crevices. This mechanism includes microbiologically influenced corrosion, pitting and crevice corrosion.  !

l 3.3.1 Microbiologically influenced Corrosion (MIC)

Microbes, primarily bacteria, have been found to cause widespread damage to low alloy and carbon steel. Similar damage has also been found at welds and heat-affected zones for austenitic stainless steel.

This system is susceptible to MIC since the components most vulnerable to MIC are those in raw  ;

water, transport systems, storage tanks or other systems containing untreated water. The SWS j contains raw water. MIC is potentially operative for both carbon steel and stainless steel in the SWS, particularly in lines subject to intermittent flow, continuous low flow (<5 fps) or stagnant conditions.

3.3.2 Pitting (PIT)

Pitting is a form of corrosion where the attack is localized rather than spread more uniformly over the exposed metal surface. Low flow or stagnant conditions stimulate pit formation. Low flow or stagnant conditions and the presence of oxidizing species exist in the SWS making this type of localized attack operative for both carbon steel and stainless steel.

l O

G SIR-98-011, Rev. 0 34 h StructuralIntegrityAssociates,Inc.

y 3.3.3 ' Crevice Corrosion (CC) l l C:evice corrosion is another form of corrosion where the attack is localized (in the presence of a crevice) rather than spread more uniformly over the exposed metal surface. Crevice corrosion is

- not applicable due to the fact that there are no crevice regions included within the boundaries of the service water system evaluation. There are no thermal sleeves identified in this system.

3.4 Plow Sensitive (FS)

When a high fluid velocity is combined with various other requisite factors it can result in'the erosion and/or corrosion of a piping material leading to a reduction in wall thickness.-

Mechanisms that are flow sensitive, and can create this form of degradation, include erosion-L cavitation and flow accelerated corrosion.

l~

3.4.1: Erosion-Cavitation (E-C) l Erosion-cavitation is not expected to be an active degradation mechanism in the SWS due to the

.i l

fact that the flow velocity in this system is not expected to exceed 30 ft/sec (the velocity at the l 20-inch diameter main service water header with flow of 12,000 gpm is approximately 15 ft/s l

downstream of the pumps). Flows in other small diameter lines are not expected to be l_ ,

significantly greater than this. Furthermore, if the lowest operating pressure (Pa) in the SWS is D i

. considered (45 psia) with the vapor pressure of 3 psia (Pv) at operating temperature of 105 F, it is j 1

very unlikely that the pressure drop (AP) across any of the service water pumps or valves will i L result in (Po- P,) /AP < 5. This is supported by the fact that erosion-cavitation degradation l generally occurs only in low pressure water systems with higher temperature where there is I significant throttling at orifices or control valves. l The exception to this is the region just downstream of squeeze valve 2CV-1460 which is mounted in the return header to Lake Dardanelle. The position of 2CV-1460 is determined by l level indicating controller 2LIC-1207A which provides a " demand" control signal based upon l

cooling tower basin level. Modulating 2CV-1460 in the closed direction causes an increase in n

o l SIR-98-011, Rev. 0 3-5 f StructuralIntegrityAssociates,Inc.

system back pressure and forces makeup flow to the cooling tower basin. In this case, the entire system pressure acts across the valve and the parameter (Po-Py)/AP will be less than 5. This is supported by operating experience [8,9] where erosion-cavitation caused leakage.

l 3.4.2 Flow Accelerated Corrosion (FAC) l FAC is a complex phenomenon that exhibits attributes of erosion and corrosion in combination.

Factors that influence whether FAC is an issue are velocity, dissolved oxygen, pH, moisture content of steam, and material chromium content.

Based on Reference 1, carbon steel piping with chromium content greater than 1% and austenitic stainless steel piping are not susceptible to degradation from FAC. The carbon steel piping in this system contains less than 1% chromium. However, the SWS is a low energy system operating at low temperature. The ANO-2 FAC program [10] excludes the SWS carbon steel piping segments on the basis of the high dissolved oxygen level and the presence of single phase water below 200 F. This system is therefore not susceptible to FAC.

3.5 Vibration Fatigue  ;

Vibration fatigue is not specifically made part of the EPRI risk-informed ISI process. Most documented vibrational fatigue failures in power plant pipiug indicate that they are restricted to  !

socket welds in small bore piping. Most of the vibrational fatigue damage occurs in the initiation phase and crack propagation proceeds at a rapid rate once a crack forms. As meh, this mechanism does not lend itself to typical periodic inservice examinations (i.e., volumetric, surface, etc.) as a means of managing this degradation mechanism.

Management of vibrational fatigue should be performed under an entirely separate program taking guidance from the EPRI Fatigue Management Handbook [11]. If a vibration problem is discovered, then corrective actions must be taken to either remove the vibration source or reduce the vibration levels to ensure future component operability. Frequent system walkdowns, leakage monitoring systems, and current ASME Section XI system leak test requirements are some of the SIR-98-0I1, Rev. 0 3-6 h StructuralIntegrity Associates, Inc.

i i

. practical measures to address this issue. Because these measures are employed either singly or in O combination for most plant systems it is not necessary to use a risk-informed inspection selection process for vibration fatigue.

l I

l 3.6 Water Ha==*r As indicated in the service history and susceptibility review section of Reference 12, ANO-2 has experienced water hammer events in the service water system. Lake Dardanelle is located at a

- relatively low elevation with respect to piping and equipment. In the event of loss of power to the service water pumps, the piping at the higher elevations will void since atmospheric pressure can only support a column of water on the order of 30 feet. The higher elevation piping thus becomes filled with water vapor. Upon restoration of emergency power the service water pump discharge pressure is restored. This can cause an excessively rapid refill of the piping as the void collapses which results in a water hammer. To preclude future water hammer occurrences, the following l design changes have been implemented.

3.6.1 Outside Containment The service and auxiliary cooling water piping and equipment located outside of containment will be protected from voiding at the higher elevations by modifications made by Design Change Package 89-2049. This design change installed components called " air and vacuum valves"

; (AVVs - single device air / vacuum valves) in the discharge piping of the equipment. Should a loss of offsite power event occur which causes the SW pumps to be deenergized, the AVVs will 1

allow air to enter the SW discharge piping as the headers drain. This will prevent water vapor 1 i

from being formed in these sections of piping. When the SW pumps are restarted, the air and l i

vacuum valves will expel the air that entered the system. In addition, since the service and auxiliary cooling water system are open (i.e., not closed-loop), any air remaining in the piping sections will be pushed out and discharged to Lake Dardanelle by restarting the service water l i pumps. <

l O l

SIR-98-011, Rev. 0 3-7 (StructuralIntegrity Associates, Inc.

l

(~3 The service water discharge piping to the Unit I circulating water discharge plenum was also modified. The discharge pipe " tailpiece" was cut such that it ends above the water level in the discharge plenum instead of below, creating an air gap. This air gap will prevent some of the service water and auxiliary cooling water components from voiding after a loss of offsite power.

3.6.2 Inside Containment AVVs cannot be used inside containment since they would draw a post-accident atmosphere into the service water piping. A " slow-refill" system is used instead for SW piping sections inside  !

containment to protect the containment service water cooling coils and their piping. i l

l l

The supply header valves to the cooling coils are normally closed valves which receive an open i signal upon a containment cooling actuation signal or a main steam isolation signal. There is a bypass line installed around each of these valves with a normally open, energize-to-close solenoid valve. The purpose of this bypass line is to allow a slow fill of the supply header in the (9

V event of an Engineered Safeguard Features (ESP) actuation coincident with a loss of offsite power. In this accident condition, the supply header will drain slowly through the bypass line.

When the service water pumps are restarted after power is restored, the supply header will refill slowly through the bypass line preventing water hammer. The supply header is allowed to refill through the bypass line because of a time delay in the opening of the supply valves.

(

SIR-98-011, Rev. 0 3-8 h StructuralIntegrityAssociates,Inc.

ym Table 3-1 l V- Degradation Mechanism Criteria and Susceptible Regions Degradation Mechanism Criteria Susceptible Regions TF TASCS - NPS > 1 inch, and nozzles, branch pipe

! connections, safe ends,

- pipe segment has a slope < 45' from horizontal (includes elbow or tee into a vertical pipe), and welds, heat affected l

l

- potential exists for low flow in a pipe section connected to a zones (HAZ), base component allowing mixing of hot and cold fluids, or metal, and regions of potential exists for leakage flow past a valve (i.e., in-leakage, stress concentration out-leakage, cross-leakage) allowing mixing of hot and cold fluids, or potential exists for convection heating in dead-ended pipe sections connected to a source of hot fluid, or potential exists for two phase (steam / water) flow, or ,

potential exists for turbulent penetration in branch pipe i connected to header piping containing hot fluid with high {

turbulent flow, and '

- calculated or measured AT > 50*F, and

- Richardson number > 4.0 ,

a TI' - operating temperature > 270*F for stainless steel, or operating temperature > 220'F for carbon steel, and i p - potential for relatively rapid temperature changes including cold fluid injection into hot pipe segment, or i hot fluid injection into cold pipe segment, and j AT > 200'F for stainless steel, or AT > 150'F for carbon steel, or AT > AT allowable (applicable to both stainless and carbon)

SCC IGSCC - evaluated in accordance with existing plant IGSCC program per austenitic stainless steel l (BWR) NRC Genetic Letter 88-01 welds and HAZ IGSCC - operating temperature > 200*F and (PWR) - susceptible material (carbon content 2 0.035%). and

- tensile stress (including residual stress)is present, and

- oxygen or oxidizing species are present OR

- operating temperature < 200'F, the attributes above apply, and

- initiating contaminants (e.g., thiosulfate, fluoride, chloride) are also required to be present TGSCC - operating temperature > 150'F, and austenitic stainless steel

- tensile stress (including residual stress) is present, and Ae metal, welds, and

- halides (e.g., fluoride, chloride) are present, or HAZ caustic (NaOH)is present, and

- oxygen or oxidizing species are present (only require.d to be present in conjunction w/ halides, not required w/ caustic)

SIR-98-011, Rev,0 3-9 f StructuralIntegrityAssociates,Inc.

( Table 3 1 (Cont'd)

( Degradation Mechanism Criteria and Susceptible Regions Degradation Mechah Cdteda Susceptible Regions SCC ECSCC - operating temperature > 150'F, and austenitic stainless steel

- tensile stress is present, and base metal, welds, and

- an outside piping surface is within five diameters of a probable HAZ leak path (e.g., valve stems) and is covered with non-metallic insulatin 0.at i: not in compliance with Reg. Guide 1.36, or an Ntside piping surfsce is exposed to wetting from chloride bearing environments (e.g., seawater, brackish water, brine)

PWSCC -- piping material is inconel (Alloy 600), and nozzles, welds, and HAZ

- exposed to primary water at T > 620*F, and without stress relief

- the material is mill-annealed and cold worked, or cold worked and welded without stress relief LC MIC - operating temperature < 150*F, and fittings, welds, HAZ,

- low or intermittent flow, and base metal, dissimilar

- pH < 10, and metal joints (e.g., welds,

- presence / intrusion of organic material (e.g., raw water system), flanges), and regions or contaimng crevices water source is not treated w/ biocides (e.g., refueling water tank)

PIT - potential exists for low flow, and s - oxygen or oxidizing species are present, and

- initiating contaminants (e.g., fluoride, chloride) are present CC - crevice condition exists (e.g., thermal sleeves), and

- operating temperature > 150'F, and j

- oxygen or oxidizing species are present FS E-C - operating temperature < 250'F, and fittings, welds, HAZ, and  !

- flow present > 100 hrs /yr, and base metal

- velocity > 30 ft/s, and ,

- (P4- P,) / AP < $ l FAC - evaluated in accordance with existing plant FAC program per plant FAC program

/~%

d

~ SIR-98-011, Rev. 0 3-10 f StructuralIntegrity Associates, Inc.

4.0

SUMMARY

AND CONCLUSION The potential for Localized Corrosion, specifically, microbiologically influenced corrosion (MIC) and pitting (PIT), has been determined to exist throughout the entire ANO-2 SWS. Accordingly, a damage group has been assigned for this mechanism as SWS-LC. A second damage group SWS-LC, FS has been assigned for the specific region immediately downstream of 2CV-1460, where flow sensitive attack due to erosion-cavitation (E-C) has been identified as a potential damage i

mechanism in addition to localized corrosion. Both damage groups result in a "small leak" failure -

potential. A summary of the evaluation is provided in Table 4-1 below.

l Table 4-1 Damage Groups Damage Damage Mech ==i=== Failure Group Thermal Fadsue Stress Corrosion Cracking Localised Corrosion Mow Sensitive Potential ID TASCS TT IGSCC TGSCC ECSCC PWSCC MIC PIT CC E-C FAC Category SWS-If No No No No No No Yes Yes No No ' No Smallleak l l SWS-II, FS No No No No No No Yes Yes No Yes No Small Leak l ,

l.  !

1' i

l l

SIR-98-011, Rev. 0 4-1 h StructuralIntegrityAssociates,Inc.

t

5.0 - REFERENCES

1. EPRI Report No. TR-106218 Interim Report, January 1996, " Risk-Informed Inservice Inspection Evaluation Procedure."
2. Duke Engineering & Services (formerly Yankee Atomic Electric Company) Document NSD-023, " Consequence Evaluation of ANO-2 Service Water System," Revision 0.
3. Arkansas Nuclear One Unit 2, " Piping and Instrument Diagram Service Water System,"

Drawing No. M-2210, Sheet 1, Revision 75.

4. Arkansas Nuclear One Unit 2, " Piping and Instrument Diagram Service Water System,"

Drawing No. M-2210, Sheet 2, Revision 73.

5. Arkansas Nuclear One Unit 2, " Piping and Instrument Diagram Service Water System,"

' Drawing No. M-2210, Sheet 3, Revision 76.

- 6. Arkansas Nuclear One Unit 2, " Piping and Instrument Diagram Emergency Diesel Generator Auxiliary System," Drawing No M-2217, Sheet 3, Revision 11.

7. Arkansas Nuclear One Unit 2, "ANO Unit 2 Plant Piping Line List (M-2083)," dated 3/31/96.

8.' Arkansas Nuclear One Unit 2, ANO CR-2-90-0385, August 1990.

9. Arkansas Nuclear One Unit 2, ANO CR-2-91-0535, October 1991.

- 10. Arkansas Nuclear One Unit 2, "ANO-2 Flow Accelerated Corrosion System Susceptibility Report," ANO Report No. 95-R-2004-01, Rev. O, dated 8/l8/95.

O SIR-98-011 Rev. 0 5-1 StructuralIntegrity Associates, Inc.

11. Riccardella, P. C., et al., "EPRI Fatigue Management Handbook," EPRI TR-104534, Electric Power Research Institute, Palo Alto, CA, December 1994.

l

12. Structural Integrity Associates, Report No. SIR-98-026, Revision 0, " Service History and j Susceptibility Review, Risk Evaluation and Element Selection for the Service Water i System at Arkansas Nuclear One Unit 2."

I i

l j

l I

I l

i i

l O

SIR-98-011 Rev. 0 5-2 h StructuralIntegrityAssociates,Inc.

L

Retrieved from "https://kanterella.com/w/index.php?title=ML20217N877&oldid=3539236"