20.08.2015   Estimating Loss-of-Coolant Accident (LOCA) Frequencies Through the Elicitation Process

ATTACHMENT D TO APPENDIX D

SIGNIFICANT FAILURES OF SAFETY RELATED PIPING

Table D. D.1 is a list of selected significant pipe failures during the period 1970 — 2003. The list includes failures of Code Class 1 and 2 piping systems inside the containment/drywell and auxiliary/reactor building structures of commercial nuclear power plants. The technical information has been extracted from the OPDE database (Attachment A).

Table D. D.1 Selected Historical Pipe Failure Information

Event

Date

Plant

Country

Estimated Peak Leak/Flow Rate [gpm]

Description

12/14/02

Brunsbuttel

(BWR)

Germany

(see Description)

Rupture of reactor head cooling pipe (the rupture occurred in section of pipe that was separated from the RPV through an isolation valve — no RPV steam leakage observed

11/7/02

Hamaoka-1

(BWR)

Japan

>> 50

Rupture of pipe in High Pressure Coolant Injection system; the rupture occurred during a functional system test

7/12/99

Tsuruga-2

(PWR)

Japan

16

Thermal fatigue induced fracture of elbow connected to regenerative heat exchanger

5/12/98

Civaux-1

(PWR)

France

131

Thermal fatigue induced fracture of seam welded elbow in the Residual Heat Removal System

5/27/97

Calvert Cliffs-1 (PWR)

USA

8.0

Fractured pressurizer instrument sensing line; attributed to vibration fatigue

4/21/97

Oconee-2

(PWR)

USA

12.0

Thermal fatigue induced fracture of weld connecting HPI/NMU pipe to RCS (see Base Case PWR-3)

12/21/96

Dampierre-1

(PWR)

France

0.6

Thermal-fatigue induced weld crack in straight section of Safety Injection line to RCS hot leg.

3/8/95

Borssele

(PWR)

The

Netherlands

65.8

While in hot standby prior to startup a weld fractured on the High Head Safety Injection common discharge header; attributed to vibration-fatigue

2/23/95

Biblis-B

(PWR)

Germany

15.8

Thermal fatigue induced fracture of base metal of pipe in Chemical and Volume Control system

3/3/94

Kola-2

(PWR)

Russia

S-LOCA

Soviet-designed PWR of type WWER- 440/230; full circumferential fracture of NPS2 makeup pipe while shutting down for maintenance outage. Event resulted in High Pressure Safety Injection system actuation; a beyond-design basis accident.

9/20/92

Dampierre-2

(PWR)

France

3.2

Non-isolable, thermal fatigue induced weld fracture in Safety Injection System.

6/18/88

Tihange-1

Belgium

6.3

Thermal fatigue induced fracture of base

Table D. D.1 Selected Historical Pipe Failure Information

Event

Date

Plant

Country

Estimated Peak Leak/Flow Rate [gpm]

Description

(PWR)

metal of Safety Injection line to RCS hot

leg

12/9/87

Farley-2

(PWR)

USA

0.7

Thermal fatigue induced weld fracture in Safety Injection line to RCS cold leg

8/16/87

McGuire-1

(PWR)

USA

39.5

Fracture (80% of circumference) of 1-inch socket weld in drain line off of letdown line inside containment. The weld fracture occurred during startup operations (8% reactor power)

5/31/86

Obrigheim

(PWR)

Germany

0.32

Thermal fatigue induced weld fracture in makeup line to RCS.

7/29/85

Sequoyah-2

(PWR)

USA

60.0

Fractured sample line in Chemical and Volume Control system; attributed to vibration-fatigue

8/6/84

McGuire-2

(PWR)

USA

8.0

Water hammer induced fracture of socket weld in letdown line

1/25/83

Maine Yankee (PWR)

USA

100

Fractured main feedwater pipe adjacent to weld joining pipe and steam generator safe end; attributed to severe water hammer.

1/21/82

Crystal River-3 (PWR)

USA

1

140-degree circumferential crack in makeup line near valve-to-safe end weld; attributed to thermal fatigue

2/12/80

Santa Maria de Garona (BWR)

Spain

0.8

IGSCC induced through-wall flaw in Reactor Recirculation nozzle-to-safe end weld

8/29/80

TVO-1

(BWR)

Finland

315

Thermal fatigue induced fracture of tee in Reactor Water Cleanup system. The fracture occurred during the commissioning of this reactor unit.

6/14/78

Duane Arnold (BWR)

USA

3.0

IGSCC induced through-wall flaw in Reactor Recirculation nozzle-to-safe end weld

11/13/73

Indian Point-2 (PWR)

USA

15.8

180-degree circumferential crack of 18- inch feedwater line weld inside containment

4/28/70

H. B. Robinson-2 (PWR)

USA

>> 50[14]

360-degree break in 6-inch branch line between No. 3 steam generator main steam line and safety valve. The failure occurred during the final stages of hot functional testing

PIPING BASE CASE RESULTS OF
WILLIAM GALYEAN

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