Information Notice 2001-09, Main Feedwater System Degradation in Safety-Related ASME Code Class 2 Piping Inside the Containment of a Pressurized Water Reactor

Main Feedwater System Degradation in Safety-Related ASME Code Class 2 Piping Inside the Containment of a Pressurized Water Reactor

ML011490408
Person / Time
Issue date:	06/12/2001
From:	Marsh L Operational Experience and Non-Power Reactors Branch
To:
Telson, R - NRR/DRIP/REXB - 415-1175
References
IN-01-009
Download: ML011490408 (18)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001

June 12, 2001

NRC INFORMATION NOTICE 2001-09:

MAIN FEEDWATER SYSTEM DEGRADATION IN

SAFETY-RELATED ASME CODE CLASS 2 PIPING

INSIDE THE CONTAINMENT OF A PRESSURIZED

WATER REACTOR

Addressees

All holders of operating licenses for pressurized water nuclear power reactors except those who

have ceased operations and have certified that fuel has been permanently removed from the

reactor vessel.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to alert

addressees to the discovery of main feedwater (MFW) system wall thinning to below allowable

limits in turbine building components and in risk-important, safety-related portions of American

Society of Mechanical Engineers (ASME) Code Class 2 piping inside the reactor containment

building (containment) at the Callaway Plant.

It is expected that recipients will review the information for applicability to their facilities and

consider actions, as appropriate. However, suggestions contained in this IN are not NRC

requirements; therefore, no specific actions or written response is required.

Description of Circumstances

During a refueling outage that began on April 7, 2001, the Callaway Plant licensee conducted

scheduled inspections to assess the effects of erosion/corrosion on steel piping exposed to

flowing water (single-phase fluids) and water-steam mixtures (two-phase fluids). These effects

are commonly referred to as flow-accelerated corrosion (FAC). Inspections identified several

instances of localized MFW system piping wall thinning to below the minimum thickness

required by ASME Boiler and Pressure Vessel Code,Section III, for safety-related piping, and

to below the minimum thickness specified by American National Standards Institute (ANSI)

B31.1, Power Piping, for non-safety-related portions of the MFW system. The wall

thicknesses in the degraded areas had not been previously measured.

The licensee had expanded and upgraded its FAC program following an August 11, 1999, event in which an 8-inch moisture separator reheater drain line experienced a double-ended

guillotine break causing operators to manually trip the reactor. The upgraded and expanded

FAC program, utilizing CHECWORKS' Rev. F software, predicted wall thinning in the MFW

system. However, without wall thickness trending data, the software was not able to accurately

predict the extent of degradation. After performing an inspection during the current outage, the

licensee found the MFW degradation to be more extensive than anticipated.

Based on the licensees initial findings and on additional industry information, FAC inspections

were expanded to include portions of the condensate system, auxiliary feedwater (AFW)

system, feedwater heaters, and other areas. Additional degradation was found in piping for the

feedwater heaters.

Several instances of MFW system wall thinning were identified in risk-important sections of

14-inch ASME Code Class 2 safety-related piping components inside the containment. The

licensee identified six 90-degree elbows, two 45-degree elbows, one 14-to-16-inch expander, and a 6-foot section of piping that had degraded to less than the ASME minimum design

allowable wall thickness (below allowance) or that the licensee projected would degrade below

allowance during the following cycle. The as-found wall thicknesses for components degraded

below allowance ranged from 75 to 96 percent of the minimum allowable thickness required by

the code. These components were identified in common MFW/auxiliary feedwater (AFW) flow

paths to three of the units four steam generators (SGs). All safety-related components in the

containment that were below allowance (or that the licensee predicted would degrade below

allowance during the following cycle) were replaced. Some degraded non-safety-related

components outside the containment were repaired rather than replaced.

Background

Since 1982, the NRC has issued numerous generic communications addressing various issues

and events related to pipe wall thinning. Several of those communications are particularly

relevant to the recently identified MFW wall-thinning at Callaway Plant. They are summarized

below and annotated in Table 1, "Summary of Related Previous Generic Communications.

Table 2 is a brief chronology of previously identified pipe wall thinning issues and events.

IN 87-36, Significant Unexpected Erosion of Feedwater Lines, August 4, 1987, addressed the

1987 discovery of MFW degradation at the Trojan Nuclear Plant similar to that observed at

Callaway Plant. The thinning was discovered when Trojans steam piping inspection program

was expanded to include single-phase piping. It was attributed to high fluid flow velocities and

other operating factors.

IN 88-17, Summary of Responses to NRC Bulletin 87-01, Thinning of Pipe Walls in Nuclear

Power Plants, April 22, 1988, summarized licensee responses to and NRC observations on

the thinning of nuclear power plant pipe walls. The IN noted that all licensees reported having

established programs for inspecting pipe wall thinning for two-phase, high-energy carbon steel

piping systems. Inspection locations were generally reported to have been selected in

accordance the 1985 guidelines in Electric Power Research Institute (EPRI) Document

NP-3944, Erosion/Corrosion in Nuclear Plant Steam Piping: Causes and Inspection Program

Guidelines. However, because implementation of these guidelines was not required, the

scope of the programs varied significantly from plant to plant.

Generic Letter 89-08, Erosion/Corrosion-Induced Pipe Wall Thinning, May 2, 1989, requested

licensees to implement long-term erosion/corrosion monitoring programs to provide assurance

that procedures or administrative controls were in place to maintain the structural integrity of all

carbon steel systems carrying high-energy fluids. EPRI released the pipe wall thinning

predictive computer code CHEC' in June 1987, CHECMATE' in April 1989, and

CHECWORKS' in August 1994, to assist licensees in selecting for testing those areas of the piping systems with the highest probabilities of wall thinning. The Massachusetts Institute of

Technology method described in NUREG/CR-5007, Prediction and Mitigation of Erosion- Corrosive Wear in Secondary Piping Systems of Nuclear Power Plants, September 1987, also

ranked systems and components according to their erosion/corrosion susceptibility.

IN 93-21, Summary of NRC Staff Observations Compiled During Engineering Audits or

Inspections of Licensee Erosion/Corrosion Programs, March 25, 1993, addressed NRC

observations on the industrys design and implementation of erosion/corrosion programs in

response to Generic Letter 89-08. Among other observations, the IN identified instances of

erosion/corrosion in safety-related portions of MFW and main steam systems and described the

problems licensees were having in implementing effective FAC programs. In November 1993, EPRI released document NSALC-202L, Recommendations for an Effective Flow-Accelerated

Corrosion Program. Rev. 2 of the document was released in April 1999.

Discussion

Although the MFW degradation was identified and addressed by the licensee before

catastrophic failure, the extent of the degradation at the time of discovery is of concern to the

NRC, given the maturity of the industrys FAC programs. Of particular concern is the

degradation in risk-important non-isolable sections of single-phase ASME Code Class 2 piping

inside the containment. These factors can impact the safety significance of pipe wall thinning.

MFW systems, like other power conversion systems, are important to the safe operation of

nuclear power plants. Past failures of feedwater and other high-energy system components

have resulted in complex challenges to operating staff when the released high-energy steam

and water interacted with other systems, such as electrical distribution, fire protection, and

security systems. Personnel injuries and fatalities have also occurred. The failure to maintain

high energy piping and components within allowable thickness values can (1) increase the

initiating event frequency for transients with loss of the power conversion system, main steam

line breaks, and other initiating events due to system interactions with high-energy steam and

water; (2) adversely affect the operability, availability, reliability, or function of systems required

for safe shutdown and accident mitigation; and/or (3) impact the integrity of fission product

barriers. This IN requires no specific action or written response. If you have any questions about the

information in this notice, please contact one of the technical contacts listed below or the

appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

/RA/

Ledyard B. Marsh, Chief

Events Assessment, Generic Communications

and Non-Power Reactors Branch

Division of Regulatory Improvement Programs

Office of Nuclear Reactor Regulation

Technical contacts:

Ross Telson, NRR

Krzysztof Parczewski, NRR

301-415-1175

301-415-2705 E-mail: rdt@nrc.gov

E-mail: kip@nrc.gov

William D. Johnson, R-IV

David Terao, NRR

817-860-8148

301-415-3317 E-mail: wdj@nrc.gov

E-mail: dxt@nrc.gov

Attachments:

1.

Table 1: Summary of Related Previous Generic Communications

2.

Table 2: Summary of Previously Identified Pipe Wall Thinning Issues and Events

3.

List of Recently Issued NRC Information Notices This IN requires no specific action or written response. If you have any questions about the

information in this notice, please contact one of the technical contacts listed below or the

appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

/RA/

Ledyard B. Marsh, Chief

Events Assessment, Generic Communications

and Non-Power Reactors Branch

Division of Regulatory Improvement Programs

Office of Nuclear Reactor Regulation

Technical contacts:

Ross Telson, NRR

Krzysztof Parczewski, NRR

301-415-1175

301-415-2705 E-mail: rdt@nrc.gov

E-mail: kip@nrc.gov

William D. Johnson, R-IV

David Terao, NRR

817-860-8148

301-415-3317 E-mail: wdj@nrc.gov

E-mail: dxt@nrc.gov

Attachments:

1.

Table 1: Summary of Related Previous Generic Communications

2.

Table 2: Summary of Previously Identified Pipe Wall Thinning Issues and Events

3.

List of Recently Issued NRC Information Notices

DISTRIBUTION

Public

REXB R/F

IN File

• See Previous Concurrence

Accession No.: ML011490408 Template No.:NRR-056

Publicly Available

 Non-Publicly Available
Sensitive Non-Sensitive

OFFICE

REXB

Tech Editor

C:EMCB

C:EMEB

NAME

RTelson*

PKleene*

WBateman*

EImbro*

DATE

5/ 21 /01

5 /18 /01

5/15 /01

5 /29 /01 OFFICE

SC:REXB

C:REXB

NAME

JTappert*

LMarsh

DATE

6/5 /01

6 /11/01

OFFICIAL RECORD COPY

Attachment 1 Table 1: Summary of Related Previous Generic Communications

The titles of generic communications referenced in the text of this IN or considered

particularly relevant are underlined.

1.

IN 82-22, Failures in Turbine Exhaust Lines, July 9, 1982, addressed the rupture of a

24-inch-diameter long-radius elbow in a feedwater heat extraction line at Oconee Unit 2 and four similar failures identified by the Institute of Nuclear Power Operations (INPO).

2.

IN 86-106, Feedwater Line Break, December 16, 1986, addressed a potentially generic

problem with feedwater pipe thinning and other problems related to the catastrophic

failure of an 18-inch-diameter MFW pump suction line at Surry Unit 2.

3.

IN 86-106, Supplement 1, Feedwater Line Break, February 13, 1987, discussed the

licensees failure analysis, the parameters that could have potentially contributed to pipe

break, the predictive measures used to detect erosion/corrosion, and the inservice

inspection requirements of ASME Code for Code Class 1 and 2 piping systems and of

ANSI B31.1 for other piping systems.

4.

IN 86-106, Supplement 2, Feedwater Line Break, October 21, 1988, addressed the

discovery that an elbow installed on the suction side of a MFW pump during a 1987 Surry

Unit 2 refueling outage had thinned more rapidly than expected, giving up 20 percent of its

0.500-inch wall thickness in 1.2 years. Wall thinning was also observed in safety-related

MFW piping and in other non-safety-related condensate piping.

5.

IN 86-106, Supplement 3, Feedwater Line Break, November 10, 1988, further addressed

the faster-than-expected wall thinning at Surry Unit 2, noting the disparity between the

previously estimated 20-30 mils/year thinning rate and maximum observed rate of

90 mils/year. The IN also noted that accelerated wall thinning may have coincided with a

reduction in feedwater dissolved-oxygen concentration.

6.

NRC Bulletin 87-01, Thinning of Pipe Walls in Nuclear Power Plants, July 9, 1987, requested licensees to inform the NRC about their programs for monitoring the thickness

of pipe walls of carbon steel piping in both safety-related and non-safety-related high- energy fluid (single-phase and two-phase) systems.

7.

IN 87-36, Significant Unexpected Erosion of Feedwater Lines, August 4, 1987, addressed potentially generic unexpected erosion which resulted in pipe wall thinning in

both safety-related and non-safety-related portions of feedwater lines (both inside and

outside the containment) at Trojan Nuclear Plant. The thinning was discovered when

Trojans steam piping inspection program was expanded to include single-phase piping

and was attributed to high fluid flow velocities and other operating factors.

8.

IN 88-17, Summary of Responses to NRC Bulletin 87-01, Thinning of Pipe Walls in

Nuclear Power Plants, April 22, 1988, reported the results of responses to NRC Bulletin

87-01 and described a recent event at LaSalle County Station Unit 1.

Attachment 1 9.

IN 89-01, Valve Body Erosion, January 4, 1989, addressed a potential generic problem

with erosion in carbon steel valve bodies in safety-related systems.

10.

Generic Letter 89-08, Erosion/Corrosion-Induced Pipe Wall Thinning, May 2, 1989, requested licensees to implement long-term erosion/corrosion monitoring programs to

obtain assurance that procedures or administrative controls were in place to maintain the

structural integrity of all carbon steel systems carrying high-energy fluids.

11.

IN 89-53, Rupture of Extraction Steam Line on High Pressure Turbine, June 13, 1989, addressed a potential generic problem with erosion in carbon steel piping in secondary

plant systems.

12.

IN 91-18, High Energy Pipe Failures Caused by Wall Thinning, March 12, 1991, addressed continuing erosion/corrosion of high-energy piping systems and apparently

inadequate monitoring programs.

13.

IN 92-35, Higher Than Predicted Erosion/Corrosion in Unisolable Reactor Coolant

Pressure Boundary Piping Inside Containment at a Boiling Water Reactor, May 6, 1992, addressed an unexpectedly high rate of erosion/corrosion in certain main feedwater piping

inside the containment at the Susquehanna Unit 1 boiling water reactor (BWR). The

condition was noted to be of particular concern since it was in a section of piping that

could not be isolated from the reactor vessel.

14.

IN 93-21, Summary of NRC Staff Observations Compiled During Engineering Audits or

Inspections of Licensee Erosion/Corrosion Programs, March 25, 1993, addressed NRC

observations on the industrys design and implementation of erosion/corrosion programs

in response to Generic Letter 89-08.

15.

IN 95-11, Failure of Condensate Piping Because of Erosion/Corrosion at a Flow- Straightening Device, February 24, 1995, addressed possible piping failures caused by

flow disturbances that were not accounted for in erosion/corrosion programs.

16.

IN 97-84, Rupture in Extraction Steam Piping as a Result of Flow-Accelerated Corrosion, December 11, 1997, addressed potential generic problems related to the occurrence and

prediction of flow-accelerated corrosion (FAC) in extraction steam lines.

17.

IN 99-19, Rupture of the Shell Side of a Feedwater Heater at the Point Beach Nuclear

Plant, June 23, 1999, addressed the rupture of the shell side of a feedwater heater at the

Point Beach Nuclear Plant Unit 1.

Attachment 2 Table 2: Summary of Previously Identified Pipe Wall Thinning Issues and Events

Date

Site

Details

Ref.

1976 Oconee 3 Pinhole leak in an extraction steam line. A surveillance program

utilizing ultrasonic examination of extraction steam lines was

initiated and, in 1980, identified two degraded elbows identical

to the Unit 2 elbow that subsequently failed in 1982. The

elbows were replaced.

IN 82-22

1981 Millstone 2 Use of engineering personnel unfamiliar with plant operating

conditions, plant as-built designs, or erosion/corrosion history.

IN 93-21 January

1982 Vermont

Yankee

Licensee shut down the plant after identifying steam blowing

from a leak in the 12-inch-diameter drain line between a

moisture separator and heater drain tank.

IN 82-22 January

1982 Trojan

Steam line failure resulting in plant shutdown.

IN 82-22 February

1982 Zion 1 Steam leak in 150 psig high-pressure exhaust steam line

originating from an 8-inch crack on a weld joining 24-inch piping

with the 37.5-inch high-pressure steam exhaust piping leading

to the moisture separator reheater. The event resulted in plant

shutdown.

IN 82-22 June 1982 Oconee 2 While operating at 95-percent power, a 4-square-foot rupture

occurred in a 24-inch-diameter long-radius elbow in a feedwater

heat extraction line. The reactor was manually tripped, a steam

jet destroyed a non-safety-related load center and certain non- safety-related instrumentation. Personnel were hospitalized

overnight with steam burns. An ultrasonic inspection had

identified substantial erosion of the elbow In March 1982, but

the erosion failed to meet the licensees criteria for rejection.

IN 82-22 June 1982

Browns Ferry 1

Steam line failure resulting in plant shutdown.

IN 82-22 March

1983 Dresden 3 Steam leak from the shell side of the 3C3 low-pressure

feedwater heater near the extraction steam inlet nozzle. The

leak was attributed to erosion by deflected extraction steam.

The feedwater heaters had not been included in a periodic

inspection program.

IN 99-19 March

1985 Haddam Neck

Pipe rupture, approximately 1/2-by-2-1/4-inch, downstream of a

normal level control valve for a feedwater heater.

GL 89-08 December

1986 Surry 2 Catastrophic failure of 18-inch MFW pump suction line elbow

when a main steam isolation valve failed closed on one of the

steam generators. A 2-by-4-foot section of the elbow was blown

out and came to rest on an overhead cable tray. The reactive

force completely severed the suction line. The free end

whipped and came to rest against the discharge line for another

pump. The failure of the piping, which was carrying single- phase fluid, was caused by erosion/corrosion of the carbon steel

pipe wall. The unit had been operating at full power. An

automatic plant trip occurred and four workers suffered fatal

injuries. Released steam caused the fire suppression system to

actuate, releasing halon and carbon dioxide into emergency

switchgear. The NRC dispatched an augmented inspection

team to the site.

IN 86-106 Bulletin 87-01 IN 88-17 GL 89-08

Attachment 2 Date

Site

Details

Ref.

June 1987 Trojan

MFW degradation was discovered by the licensee in at least two

areas of the straight sections of ASME Class 2 safety-related

MFW piping inside containment. The thinning was discovered

when the Trojan steam piping inspection program was

expanded to include single-phase piping. The thinning was

attributed to high fluid flow velocities and other operating

factors.

IN 87-36 IN 88-17 GL 89-08 December

1987 LaSalle 1 Through-wall pinhole leaks due to erosion were discovered in a

45-degree elbow down stream of a turbine-driven reactor

feedwater pump minimum-flow control valve. Subsequent

inspections identified additional areas of wall thinning.

IN 88-17 September

1988 Surry 2 The pipe wall of an elbow installed on the suction side of a MFW

pump during a 1987 refueling outage was discovered to have

thinned more rapidly than expected, losing 20 percent of its

0.500-inch wall thickness in 1.2 years. Wall thinning was also

observed in safety-related MFW piping and in other non-safety- related condensate piping.

GL 89-08 December

1988 Brunswick 1 Inspection indicated areas of significant but localized erosion on

the internal surfaces of several carbon steel valve bodies. The

affected safety-related valves were the 24-inch residual heat

removal/low pressure core injection (RHR/LPCI) system

injection and 16-inch suppression pool isolation valves.

IN 89-01 April 1989 Arkansas

Nuclear One

Unit 2 Steam escaping from a ruptured 14-inch high-pressure steam

extraction line caused a spurious turbine/reactor trip from

100-percent power. This straight run of piping terminates at an

elbow that was replaced during the previous outage because of

erosion-induced wall thinning. The pipe and those of similar

geometries had not been included in the licensees surveillance

samples, and the degraded condition was not detected during

the elbow replacement.

IN 89-53 March

1990

Surry 1 Rupture of a straight section of piping downstream of a level

control valve in the low-pressure heater drain (LPHD) system.

The LPHD system was included in the licensees FAC program

at the time, but the program did not provide an inspection for the

affected section of piping.

IN 91-18 May 1990

Loviisa 1 (foreign)

A flow-measuring orifice flange in the main feedwater system

ruptured after one of five main feedwater pumps tripped, causing a check valve in the line to slam shut, creating a

pressure spike. Subsequent inspections determined that 9 of

10 flanges had thinned to below minimum wall requirements.

IN 91-18 July 1990

San Onofre 2

The licensee was forced to shut down the unit after discovering

a steam leak in one of the feedwater regulating valve bypass

lines.

IN 91-18 December

1990

Millstone 3 Two 6-inch pipes in the moisture separator drain (MSD) system

ruptured when a MSD pump was stopped to facilitate

component isolation for repairs. Stopping the pump caused a

pressure transient. The high-energy water flashed to steam and

actuated portions of the turbine building fire protection deluge

system. Two 480-volt motor control centers and one non-vital

120-volt inverter were rendered inoperable by the flooding, resulting in the loss of the plant process computer and the

isolation of the instrument air to the containment building.

IN 91-18

Attachment 2 Date

Site

Details

Ref.

November

1991 Millstone 2 Rupture at an 8-inch elbow of a moisture separator reheater.

High-energy water flashed to steam, actuating portions of the

turbine fire protection deluge system. The license had not

selected the ruptured elbow for ultrasonic testing in its

erosion/corrosion monitoring program. See LER 50-336/91-12.

IN 91-18

1992 Millstone 3 See LER 50-309/92-07.

IN 93-21

1992

Maine Yankee

See LER 92-007.

IN 93-21

1992 Salem 1 Improper determination of code minimum wall thickness

acceptance criteria resulted in improper disposition of degraded

components. See Inspection Report 50-272/92-08.

IN 93-21

1992 Hope Creek

Lack of baseline thickness measurements (history) of originally

designed piping was identified. See Inspection Report 50-

354/92-11.

IN 93-21

1992 Millstone 1 Lack of baseline thickness measurements of replacement piping

before the replacement piping was put into service. See

Inspection Report 50-245/92-80.

IN 93-21

1992 Hope Creek

Use of engineering personnel who are unfamiliar with plant

operating conditions, plant as-built designs, or erosion/corrosion

history.

---

-----

1993 Diablo

Canyon 1 Erosion/corrosion wear was discovered behind a thermal sleeve

in the interior of the feedwater nozzle and on the feedwater

nozzle itself.

IN 93-21 November

1994 Sequoyah 1 Licensee identified a 180-degree circumferential crack in a

reduced section of 14-inch condensate piping used for flow- metering. The section of piping had been modeled incorrectly in

CHECMATE' without any diameter or thickness changes and

had not been visually inspected.

IN 95-11 April 1997

Fort Calhoun

Manual scram and emergency boration following a 6-square- foot rupture of a 12-inch diameter sweep elbow in the fourth- stage extraction steam piping. A non-safety-related electrical

load center, several cable trays and pipe hangers were

damaged. In addition, asbestos-containing insulation was

blown throughout the turbine building and portions of the fire

protection system were actuated.

IN 97-84 May 1999

Point Beach 1

Manual trip from 100-percent power and manual safety injection

actuation when the shell side of the feedwater heater ruptured.

The fish-mouth rupture was approximately 27-inches long and

0.75-inch at its widest point. Feedwater heater leaks were also

identified at Pilgrim Station and the Susquehanna units. None

of the feedwater heaters had been included in a periodic

inspection program.

IN 99-19 August

1999 Callaway

Operators manually tripped the reactor on indication of a steam

leak in the turbine building. An 8-inch line from the first stage

reheater drain tank to the high-pressure heater experienced a

double-ended guillotine break.

Event

Notification

36015

______________________________________________________________________________________

OL = Operating License

CP = Construction Permit

Attachment 3 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

_____________________________________________________________________________________

Information

Date of

Notice No.

Subject

Issuance

Issued to

______________________________________________________________________________________

2001-08

Supplement 1

Update on the Investigation of

Patient Deaths in Panama,

Following Radiation Therapy

Overexposures

06/06/01

All Medical Licensees

2001-08

Treatment Planning System

Errors Result in Deaths of

Overseas Radiation Therapy

Patients

06/01/01

All medical licensees

2001-07

Unescorted Access Granted

Based on Incomplete and/or

Inaccurate Information

05/11/01

All holders of nuclear reactor

operating licenses who are

subject to Section 73.56 of Title

10, of the Code of Federal

Regulations (10 CFR 73.56),

Personnel Access Authorization

Requirements of Nuclear Power

Plants.

2001-06

Centrifugal Charging Pump

Thrust Bearing Damage not

Detected Due to Inadequate

Assessment of Oil Analysis

Results and Selection of Pump

Surveillance Points

05/11/01

All holders of operating licenses

for nuclear power reactors, except those who have

permanently ceased operations

and have certified that fuel has

been permanently removed from

the reactor

2001-05 Through-Wall Circumferential

Cracking of Reactor Pressure

Vessel Head Control Rod Drive

Mechanism Penetration

Nozzles at Oconee Nuclear

Station, Unit 3

04/30/01

All holders of operating licenses

for pressurized water nuclear

power reactors except those who

have ceased operations and have

certified that fuel has been

permanently removed from the

reactor vessel

2001-04

Neglected Fire Extinguisher

Maintenance Causes Fatality

04/11/01

All holders of licenses for nuclear

power, research, and test

reactors and fuel cycle facilities

2001-03

Incident Reporting

Requirements for Radiography

Licensees

04/06/01

All industrial radiography

licensees