NUREG-1022 

Rev. 2

Event Reporting Guidelines 

10 CFR 50.72 and 50.73 

U.S. Nuclear Regulatory Commission AZ 

Office Nuclear Reactor Regulation 

Washington, DC 20555-0001
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212-642-4900
NUREG-1022 

Rev. 2

Event Reporting Guidelines 

10 CFR 50.72 and 50.73

Manuscript Completed: October 2000 

Date Published: October 2000 

Division of Regulatory Improvement Programs 

Office of Nuclear Reactor Regulation 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555-0001
PAPERWORK REDUCTION ACT STATEMENT

The information collections contained in this NUREG report are covered by the requirements of 

10 CFR Part 50, which were approved by the Office of Management and Budget, approval 

number 3150-0011. 

Public Protection Notification 

If a means used to impose an information collection does not display a currently valid OMB 

control number, the NRC may not conduct or sponsor, and a person is not required to respond 

to, the information collection.

NUREG-1022, Rev. 2 ii
ABSTRACT

This Revision 2 to NUREG-1022 revises the event reporting guidelines to: implement 

amendments to 10 CFR 50.72 and 50.73; and incorporate minor revisions to the guidelines for 

the purpose of clarification.

iii NUREG-1022, Rev. 2
CONTENTS 

PAPERWORK REDUCTION ACT STATEMENT ................................... ii 

A BSTRACT ............................................................... iii 

EXECUTIVE SUMMARY ..................................................... vii 

1 INTRO DUCTIO N ......................................................... 1 

1.1 Background ..................................................... 1 

1.2 Revised Reporting Guidelines ....................................... 1 

1.3 New or Different Guidance .......................................... 2 

2 REPORTING AREAS WARRANTING SPECIAL MENTION ........................ 23 

2.1 Engineering Judgment ....................................... :.. 23 

2.2 Differences in Tense Between 10 CFR 50.72 and 50.73 .................. 23 

2.3 Reporting Multiple Events .......................................... 23 

2.4 Deficiencies Discovered During Engineering Reviews .................... 24 

2.5 Time Limits for Reporting .......................................... 24 

2.6 Events Discussed with -the NRC Staff ................................. 25 

2.7 Voluntary Reporting .............................................. 25 

2.8 Retraction or Cancellation of Event Reports ............................ 26 

3 SPECIFIC REPORTING GUIDELINES ........................................ 27 

3.1 General Requirements ............................................. 27 

3.1.1 Immediate Notifications ..................................... 27 

3.1.2 Licensee Event Reports ..................................... 29 

3.2 Specific Reporting Criteria ........................................... 29 

3.2.1 Plant Shutdown Required by Technical Specifications ............. 29 

3.2.2 Operation or Condition Prohibited by Technical Specifications ....... 32 

3.2.3 Deviation from Technical Specifications under § 50.54(x) .......... 37 

3.2.4 Degraded or Unanalyzed Condition ........................... 38 

3.2.5 External Threat or Hampering ............................... 42 

3.2.6 System Actuation ......................................... 45 

3.2.7 Event or Condition That Could Have Prevented Fulfillment of a Safety 

Function ................................................ 52 

3.2.8 Common-cause Inoperability of Independent Trains or Channels .... 64 

3.2.9 Radioactive Release ....................................... 67 

3.2.10 Internal Threat or Hampering ................................ 69 

3.2.11 Transport of a Contaminated Person Offsite .................... 71 

3.2.12 News Release or Notification of Other Government Agency ........ 72 

3.2.13 Loss of Emergency Preparedness Capabilities .................. 75

V NUREG-1022, Rev. 2
3.2.14 Single Cause that Could Have Prevented Fulfillment of the Safety 

Functions of Trains or Channels in Different Systems ............. 79 

3.3 Followup Notification ............................................... 85 

4 EMERGENCY NOTIFICATION SYSTEM REPORTING ........................... 87 

4.1 Emergency Notification System ...................................... 87 

4.2 General ENS Notification ........................................... 88 

4.2.1 Tim eliness ............................................... 88 

4.2.2 Voluntary Notifications ...................................... 88 

4.2.3 ENS Notification Retraction ................................ 88 

4.2.4 ENS Event Notification Worksheet (NRC Form 361) ............... 88 

4.3 Typical ENS Reporting Issues ....................................... 89 

5 LICENSEE EVENT REPORTS .............................................. 91 

5.1 LER Reporting Guidelines .......................................... 91 

5.1.1 Submission of LERs ....................................... 91 

5.1.2 LER Forwarding Letter and Cancellations ...................... 91 

5.1.3 Report Legibility .......................................... 92 

5.1.4 Voluntary LERs .......................................... 92 

5.1.5 Supplemental Information and Revised LERs ................... 92 

5.1.6 Special Reports .......................................... 93 

5.1.7 Appendix J Reports (Containment Leak Rate Test Reports) ........ 93 

5.1.8 10 CFR Part 21 Reports .................................... 93 

5.1.9 Section 73.71 Reports ..................................... 94 

5.1.10 Availability of LER Forms ................................... 94 

5.2 LER Content Requirements and Preparation Guidance .................... 95 

5.2.1 Optical Character Reader ................................... 95 

5.2.2 Narrative Description or Text (NRC Form 366A, Item 17) .......... 96 

5.2.3 Assessment of Safety Consequences ........................ 103 

5.2.4 Corrective Actions ....................................... 104 

5.2.5 Previous Occurrences .................................. 105 

5.2.6 Abstract (NRC Form 366, Item 16) ........................... 105 

5.2.7 Other Fields on the LER Form .............................. 106 

5.2.8 Examples of LER Forms .................................. 111 

TABLES 

1. Reportable Events ........................................................ 3 

2. Changes in Reporting Requirements .......................................... 9 

NUREG-1022, Rev. 2 vi
EXECUTIVE SUMMARY

Two of the many elements contributing to the safety of nuclear power are emergency response 

and the feedback of operating experience into plant operations. These are achieved partly by 

the licensee event reporting requirements of Title 10 of the Code of Federal Regulations, Part 

50, Sections 50.72 and 50.73 (10 CFR 50.72 and 50.73). Section 50.72 provides for 

immediate notification requirements via the emergency notification system (ENS) and Section 

50.73 provides for 60-day written licensee event reports (LERs). 

The information reported under 10 CFR 50.72 and 50.73 is used by the NRC staff in 

responding to emergencies, monitoring ongoing events, confirming licensing bases, studying 

potentially generic safety problems, assessing trends and patterns of operational experience, 

monitoring performance, identifying precursors of more significant events, and providing 

operational experience to the industry. 

This Revision 2 to NUREG-1022 revises the event reporting guidelines to: implement 

amendments to 10 CFR 50.72 and 50.73; and incorporate minor revisions to the guidelines for 

the purpose of clarification. This report supersedes Revision 1 to NUREG-1022. 

The document is structured to assist licensees in achieving prompt and complete reporting of 

specified events and conditions. It includes specific discussions of general issues that have 

been difficult to implement in the past such as engineering judgment, time limits for reporting, 

multiple failures and related events, deficiencies discovered during licensee engineering 

reviews, and human performance issues. It also includes a comprehensive discussion of each 

specific reporting criterion with illustrative examples and definitions of key terms and phrases.

vii NUREG-1 022, Rev. 2
ABBREVIATIONS

AFW auxiliary feedwater 

AIT augmented inspection team 

ASME American Society of Mechanical Engineers 

ASP accident sequence precursor 

ATWS anticipated transient without scram 

BPV Boiler and Pressure Vessel Code (ASME) 

BWR boiling-water reactor 

CFR Code of Federal Regulations 

CRDM control rod drive mechanism 

CRVS control room ventilation system 

DBDR design-basis documentation review 

DDR design document reconstitution 

ECCS emergency core cooling system 

EDG emergency diesel generator 

EFW emergency feedwater 

EIIS Energy Industry Identification System 

ENS emergency notification system 

EO emergency officer 

EOF emergency operations facility 

EOP emergency operating procedure 

EPIX equipment performance and information exchange 

EPA Environmental Protection Agency (U.S.) 

ERDS emergency response data system 

ERF emergency response facility 

ESF engineered safety feature(s) 

ESW emergency service water 

ETS Emergency Telecommunications System 

FEMA Federal Emergency Management Agency 

FFD fitness for duty 

FSAR final safety analysis report 

FTS federal telecommunications system 

GDC general design criteria 

GL generic letter

ix NUREG-1022, Rev. 2
HOO headquarters operations officer 

HP health physics 

HPCI high-pressure coolant injection 

HPCS high-pressure core spray 

HPI high-pressure injection 

HPN health physics network 

HPSI high pressure safety injection 

HVAC heating, ventilation and air conditioning 

IEEE Institute of Electrical and Electronics Engineers 

lIT incident investigation team 

ILRT integrated leak rate test 

IN information notice 

INPO Institute of Nuclear Power Operations 

ISI inservice inspection 

IST inservice testing 

ISTS improved standard technical specifications 

LCO limiting condition for operation 

LER licensee event report 

LOCA loss of coolant accident 

LPCI low-pressure coolant injection 

LPCA low-pressure core spray 

LPSW low-pressure service water 

MPC maximum permissible concentration 

MSIV main steam isolation valve 

NRC Nuclear Regulatory Commission (U.S.) 

NRR Nuclear Reactor Regulation, Office of 

NUMARC Nuclear Management and Resources Council 

OCR optical character reader 

OMS overpressure mitigation system 

PDR Public Document Room 

PGA policies, guidance, and administrative controls 

PWR pressurized water reactor 

RAB Reactor Analysis Branch 

RBVS reactor building ventilation system 

RCIC reactor core isolation cooling 

RCP reactor coolant pump 

RCS reactor coolant system 

RDO regional duty officer 

RHR residual heat removal 

RPS reactor protection system

NUREG-1022, Rev. 2 X
RWCU reactor water cleanup

SAR safety analysis report 

S/D shutdown 

SIS safety injection system 

SOV solenoid-operated valve 

SPDS safety parameter display system 

SRO senior reactor operator 

STS standard technical specifications 

TS technical specification(s) 

TSC technical support center

xi NUREG-1022, Rev. 2
1 INTRODUCTION

This document provides guidance on the reporting requirements of Title 10 of the Code of 

Federal Regulations, Part 50, Sections 50.72 and 50.73 (10 CFR 50.72 and 10 CFR 50.73). 

While these reporting requirements range from immediate, 1-hour, 4-hour and 4-8-hour 

telephone notifications to -3-60-day written reports, covering a broad spectrum of events from 

emergencies to component level deficiencies, the NRC wishes to emphasize that reporting 

requirements should not interfere with ensuring the safe operation of a nuclear power plant. 

Licensees' immediate attention must always be given to operational safety concerns. 

1.1 Background 

In 1983, partially in response to lessons from the Three Mile Island accident, the U.S. Nuclear 

Regulatory Commission (NRC) revised its immediate notification requirements via the 

emergency notification system (ENS) in 10 CFR 50.72 and modified and codified its written 

licensee event report (LER) system requirements in 10 CFR 50.73. The revision of 10 CFR 

50.72 and the new 10 CFR 50.73 became effective on January 1, 1984. Together, they 

specified the types of events and conditions reportable to the NRC for emergency response 

and identifying plant-specific and generic safety issues. They have remained in effect since 

then with only minor modifications until early 2001. 

In late October 2000, substantial amendments to 10 CFR 50.72 and 50.73 are to be published 

in the Federal Register, with an effective date in late January 2001. 

1.2 Revised Reporting Guidelines 

The purpose of this Revision 2 to NUREG-1022 is to revise the event reporting guidelines to 

implement the amendments to 10 CFR 50.72 and 50.73 that are to be published in late 

October 2000. It also incorporates minor changes to the guidelines for the purpose of 

clarification. This report supersedes Revision 1 to NUREG-1022. 

Section 2 clarifies specific areas of 10 CFR 50.72 and 50.73 that are applicable to multiple 

reporting criteria or that historically appear to be subject to varied interpretations. It covers 

such diverse subjects as engineering judgment, differences in tenses between the two rules, 

retraction and voluntary reporting, legal reporting requirements, and human performance 

issues. 

Section 3 contains guidelines on event reporting for specific criteria in both rules by means of 

discussions and examples of reported events. To minimize repetition, similar criteria from both 

rules are addressed together. Section 3.1 addresses general ENS and LER reporting 

requirements. Section 3.2 addresses specific ENS and LER reporting criteria. It includes a

1 NUREG-1022, Rev. 2
comprehensive discussion of each specific reporting criterion with illustrative examples and 

definitions of key terms and phrases. Section 3.3 addresses the requirements for immediate 

ENS followup notifications during the course of an event. 

Section 4 explains ENS communications reporting timeliness and completeness, voluntary 

notifications, and retractions. Appropriate ENS emergency notification methods are described. 

Section 5 provides guidelines on administrative requirements, preparation, and submittal of 

LERs. It specifies the information an LER should contain and provides steps to be followed in 

preparing an LER. It also includes an expanded human performance discussion to achieve 

ENS and LER content that examines both equipment and human performance. 

1.3 New or Different Guidance 

Except in Table 1, reporting guidance that is considered new or different from that provided in 

NUREG-1022, Revision 1, is indicated by underlining the appropriate text. In some cases, 

strikeout marking is also provided to show that specific items are being deleted.

NUREG-1022, Rev. 2 2
Table 1. Reportable Events

Declaration of an Emergency Class 

(See Section 3.1.1 of this report) 

§ 50.72(a)(1)(i) "The declaration of any of the 

Emergency Classes specified in the licensee's 

approved Emergency Plan." 

Plant Shutdown Required by Technical Specifications 

(See Section 3.2.1 of this report) 

§ 50.72(b)(2)(i) "The initiation of any nuclear § 50.73(a)(2)(i)(A) "The completion of any 

plant shutdown required by the plant's Technical nuclear plant shutdown required by the plant's 

Specifications." Technical Specifications." 

Operation or Condition Prohibited by Technical Specifications 

(See Section 3.2.2 of this report) 

§ 50.73(a)(2)(i)(B) "Any operation or 

condition which was prohibited by the plant's 

Technical Specifications except when: 

(1) The Technical Specification is 

administrative in nature; 

(2) The event consisted solely of a case of a 

late surveillance test where the oversight was 

corrected, the test was performed, and the 

equipment was found to be capable of performing 

its specified safety functions; or 

(3) The Technical Specification was revised 

prior to discovery of the event such that the 

operation or condition was no longer prohibited at 

the time of discovery of the event." 

Deviation from Technical Specifications Authorized under § 50.54(x) 

(See Section 3.2.3 of this report)

§ 50.72(b)(1) "..any deviation from the § 50.73(a)(2)(i)(C) "Any deviation from the 

plant's Technical Specifications authorized plant's Technical Specifications authorized 

pursuant to § 50.54(x) of this part." pursuant to § 50.54(x) of this part." 

Degraded or Unanalyzed Condition 

(See Section 3.2.4 of this report) 

§ 50.72(b)(3)(ii) "Any event or condition that § 50.73(a)(2)(ii) "Any event or condition that 

results in: resulted in: 

(A) The condition of the nuclear power plant, (A) The condition of the nuclear power plant, 

including its principal safety barriers, being including its principal safety barriers, being 

seriously degraded; or seriously degraded; or

3 NUREG-1022, Rev. 2
Reportable Events (continued)

(B) The nuclear power plant being in an (B) The nuclear power plant being in an 

unanalyzed condition that significantly degrades unanalyzed condition that significantly degraded 

plant safety." plant safety." 

External Threat or Hampering 

(See Section 3.2.5 of this report) 

§ 50.73(a)(2)(iii) Any natural phenomenon or 

other external condition that posed an actual 

threat to the safety of the nuclear power plant or 

significantly hampered site personnel in the 

performance of duties necessary for the safe 

operation of the nuclear power plant. 

System Actuation 

(See Section 3.2.6 of this report) 

§ 50.72(b)(2)(iv)(A) "Any event that results or 

should have resulted in emergency core cooling 

system (ECCS) discharge into the reactor coolant 

system as a result of a valid signal except when 

the actuation results from and is part of a 

pre-planned sequence during testing or reactor 

operation." 

§ 50.72(b)(2)(iv)(B) "Any event or condition 

that results in actuation of the reactor protection 

system (RPS) when the reactor is critical except 

when the actuation results from and is part of a 

pre-planned sequence during testing or reactor 

operation." 

§ 50.72(b)(3)(iv)(A) "Any event or condition § 50.73(a)(2)(iv)(A) "Any event or condition 

that results in valid actuation of any of the that resulted in manual or automatic actuation of 

systems listed in paragraph (b)(3)(iv)(B) of this any of the systems listed in paragraph 

section, except when the actuation results from (a)(2)(iv)(B) of this section, except when: 

and is part of a pre-planned sequence during (1) The actuation resulted from and was part 

testing or reactor operation." of a pre-planned sequence during testing or 

reactor operation; or 

(2) The actuation was invalid and; 

(i) Occurred while the system was properly 

removed from service; or 

(ii) Occurred after the safety function had 

been already completed." 

§ 50.72(b)(3)(iv)(B) "The systems to which § 50.73(a)(2)(iv)(B) "The systems to which 

the requirements of paragraph (b)(3)(iv)(A) of this the requirements of paragraph (a)(2)(iv)(A) of this

NUREG-1022, Rev. 2 4
Reportable Events (continued)

section apply are: 

(1) Reactor protection system (RPS) 

including: reactor scram and reactor trip.5 

(2) General containment isolation signals 

affecting containment isolation valves in more 

than one system or multiple main steam isolation 

valves (MSIVs). 

(3) Emergency core cooling systems (ECCS) 

for pressurized water reactors (PWRs) including: 

high-head, intermediate-head, and low-head 

injection systems and the low pressure injection 

function of residual (decay) heat removal 

systems. 

(4) ECCS for boiling water reactors (BWRs) 

including: high-pressure and low-pressure core 

spray systems; high-pressure coolant injection 

system; low pressure injection function of the 

residual heat removal system. 

(5) BWR reactor core isolation cooling 

system; isolation condenser system; and 

feedwater coolant injection system. 

(6) PWR auxiliary or emergency feedwater 

system. 

(7) Containment heat removal and 

depressurization systems, including containment 

spray and fan cooler systems. 

(8) Emergency ac electrical power systems, 

including: emergency diesel generators (EDGs); 

hydroelectric facilities used in lieu of EDGs at the 

Oconee Station; and BWR dedicated Division 3 

EDGs. 

5 Actuation of the RPS when the reactor is 

critical is reportable under § 50.72(b)(2)(iv)(B)."

T

section apply are: 

(1) Reactor protection system (RPS) 

including: reactor scram or reactor trip. 

(2) General containment isolation signals 

affecting containment isolation valves in more 

than one system or multiple main steam isolation 

valves (MSIVs). 

(3) Emergency core cooling systems (ECCS) 

for pressurized water reactors (PWRs) including: 

high-head, intermediate-head, and low-head 

injection systems and the low pressure injection 

function of residual (decay) heat removal 

systems. 

(4) ECCS for boiling water reactors (BWRs) 

including: high-pressure and low-pressure core 

spray systems; high-pressure coolant injection 

system; low pressure injection function of the 

residual heat removal system. 

(5) BWR reactor core isolation cooling 

system; isolation condenser system; and 

feedwater coolant injection system. 

(6) PWR auxiliary or emergency feedwater 

system. 

(7) Containment heat removal and 

depressurization systems, including containment 

spray and fan cooler systems. 

(8) Emergency ac electrical power systems, 

including: emergency diesel generators (EDGs); 

hydroelectric facilities used in lieu of EDGs at the 

Oconee Station; and BWR dedicated Division 3 

EDGs. 

(9) Emergency service water systems that do 

not normally run and that serve as ultimate heat 

sinks."

Event or Condition that Could Have Prevented Fulfillment of a Safety Function 

(See Section 3.2.7 of this report) 

§ 50.72(b)(3)(v) "Any event or condition that § 50.73(a)(2)(v) "Any event or condition that 

at the time of discovery could have prevented the could have prevented the fulfillment of the safety 

fulfillment of the safety function of structures or function of structures or systems that are needed 

systems that are needed to: to: 

(A) Shut down the reactor and maintain it in a (A) Shut down the reactor and maintain it in a 

safe shutdown condition; safe shutdown condition; 

(B) Remove residual heat; (B) Remove residual heat; 

(C) Control the release of radioactive (C) Control the release of radioactive 

material; or material; or 

(D) Mitigate the consequences of an (D) Mitigate the consequences of an

5 NUREG-1022, Rev. 2
Reportable Events (continued)

accident." 

§ 50.72(b)(3)(vi) "Events covered in 

paragraph (b)(3)(v) of this section may include 

one or more procedural errors, equipment 

failures, and/or discovery of design, analysis, 

fabrication, construction, and/or procedural 

inadequacies. However, individual component 

failures need not be reported pursuant to 

paragraph (b)(3)(v) of this section if redundant 

equipment in the same system was operable and 

available to perform the required safety function."

accident." 

§ 50.73(a)(2)(vi) "Events covered in 

paragraph (a)(2)(v) of this section may include 

one or more procedural errors, equipment 

failures, and/or discovery of design, analysis, 

fabrication, construction, and/or procedural 

inadequacies. However, individual component 

failures need not be reported pursuant to 

paragraph (a)(2)(v) of this section if redundant 

equipment in the same system was operable and 

available to perform the required safety function."

Common Cause Inoperability of Independent Trains or Channels 

(See Section 3.2.8 of this report)

§ 50.73(a)(2)(vii) "Any event where a single 

cause or condition caused at least one 

independent train or channel to become 

inoperable in multiple systems or two 

independent trains or channels to become 

inoperable in a single system designed to: 

(A) Shut down the reactor and maintain it in a 

safe shutdown condition; 

(B) Remove residual heat; 

(C) Control the release of radioactive 

material; or 

(D) Mitigate the consequences of an 

accident."

Radioactive Release 

(See Section 3.2.9 of this report)

§ 50.73(a)(2)(viii)(A) "Any airborne 

radioactive release that, when averaged over a 

time period of 1 hour, resulted in airborne 

radionuclide concentrations in an unrestricted 

area that exceeded 20 times the applicable 

concentration limits specified in appendix B to 

part 20, table 2, column 1." 

§ 50.73(a)(2)(viii)(B) "Any liquid effluent 

release that, when averaged over a time period 

of 1 hour, exceeds 20 times the applicable 

concentrations specified in appendix B to part 20, 

table 2, column 2, at the point of entry into the 

receiving waters (i.e., unrestricted area) for all 

radionuclides except tritium and dissolved noble

NUREG-1022, Rev. 2 6
Reportable Events (continued)

I gases." 

Internal Threat or Hampering 

(See Section 3.2.10 of this report) 

§ 50.73(a)(2)(x) "Any event that posed an 

actual threat to the safety of the nuclear power 

plant or significantly hampered site personnel in 

the performance of duties necessary for the safe 

operation of the nuclear power plant including 

fires, toxic gas releases, or radioactive releases." 

Transport of a Contaminated Person Offsite 

(See Section 3.2.11 of this report) 

§ 50.72(b)(3)(xii) "Any event requiring the 

transport of a radioactively contaminated person 

to an offsite medical facility for treatment." 

News Release or Notification of Other Government Agency 

(See Section 3.2.12 of this report) 

§ 50.72(b)(2)(xi) "Any event or situation, 

related to the health and safety of the public or 

onsite personnel, or protection of the 

environment, for which a news release is planned 

or notification to other government agencies has 

been or will be made. Such an event may 

include an onsite fatality or inadvertent release of 

radioactively contaminated materials."

Loss of Emergency Preparedness Capabilities 

(See Section 3.2.13 of this report) 

§ 50.72(b)(3)(xiii) "Any event that results in a 

major loss of emergency assessment capability, 

offsite response capability, or offsite 

communications capability (e.g., significant 

portion of control room indication, emergency 

notification system, or offsite notification 

system)." 

Single Cause that Could Have Prevented Fulfillment of the Safety Functions of 

Trains or Channels in Different Systems (See Section 3.2.14 of this report) 

50.73(a)(2)(ix)(A) "Any event or condition 

7 NUREG-1022, Rev. 2
Reportable Events (continued)

NUREG-1022, Rev. 2

that as a result of a single cause could have 

prevented the fulfillment of a safety function for 

two or more trains or channels in different 

systems that are needed to: 

(1) Shut down the reactor and maintain it in a 

safe shutdown condition; 

(2) Remove residual heat; 

(3) Control the release of radioactive 

material; or 

(4) Mitigate the consequences of an 

accident." 

§ 50.73(a)(2)(ix)(B) "Events covered in 

paragraph (ix)(A) of this section may include 

cases of procedural error, equipment failure, 

and/or discovery of a design, analysis, 

fabrication, construction, and/or procedural 

inadequacy. However, licensees are not required 

to report an event pursuant to paragraph (ix)(A) 

of this section if the event results from: 

(1) A shared dependency among trains or 

channels that is a natural or expected 

consequence of the approved plant design; or 

(2) Normal and expected wear or 

degradation."

8
Table 2. Changes in Reporting Requirements

Previous requirements. Amended requirements.

§ 50.72 Immediate notification requirements for operating nuclear power reactors.

§ 50.72(a) General requirements.1 § 50.72(a) General requirements.' 

1 Other requirements for immediate notification of 1 Other requirements for immediate notification of 

the NRC by licensed operating nuclear power reactors the NRC by licensed operating nuclear power reactors 

are contained elsewhere in this chapter, in particular are contained elsewhere in this chapter, in particular 

§§ 20.1906, 20.2202, 50.36, and 73.71. §§ 20.1906, 20.2202, 50.36, 72.216, and 73.71. 

§ 50.72(a)(1) Each nuclear power reactor licensee § 50.72(a)(1) Each nuclear power reactor licensee 

licensed under § 50.21(b) or § 50.22 of this part shall licensed under § 50.21(b) or § 50.22 of this part shall 

notify the NRC Operations Center via the Emergency notify the NRC Operations Center via the Emergency 

Notification System of: Notification System of: 

(i) The declaration of any of the Emergency (i) The declaration of any of the Emergency 

Classes specified in the licensee's approved Classes specified in the licensee's approved 

Emergency Plan;2 or Emergency Plan;2 or 

(ii) Of those non-Emergency events specified in (ii) Those non-emergency events specified in 

paragraph (b) of this section. paragraph (b) of this section that occurred within three 

years of the date of discovery. 

2 These Emergency Classes are addressed in Footnote 2 is unchanged. 

Appendix E of this part. 

§ 50.72(a)(2) If the Emergency Notification Unchanged. 

System is inoperative, the licensee shall make the 

required notifications via commercial telephone 

service, other dedicated telephone system, or any 

other method which will ensure that a report is made 

as soon as practical to the NRC Operations Center.3 4 

3 Commercial telephone number of the NRC Footnote 3 is unchanged. 

Operations Center is (301) 816-5100. 

_! fReservedl Former Footnote 4 is deleted. 

§ 50.72(a)(3) The licensee shall notify the NRC Unchanged. 

immediately after notification of the appropriate State 

or local agencies and not later than one hour after the 

time the licensee declares one of the Emergency 

Classes. 

§ 50.72(a)(4) The licensee shall activate the Unchanged. 

Emergency Response Data System (ERDS)ý as soon 

as possible but not later than one hour after declaring 

an Emergency Class of alert, site area emergency, or 

general emergency. The ERDS may also be activated 

by the licensee during emergency drills or exercises if 

the licensee's computer system has the capability to 

transmit the exercise data. 

_ Requirements for ERDS are addressed in Former Footnote 5 is renumbered 4. Otherwise 

Appendix E, Section VI. unchanged.

9 NUREG-1022, Rev. 2
Changes in Reporting Requirements (continued)

Previous requirements. Amended requirements.

§ 50.72(a)(5) When making a report under § 50.72(a)(5) When making a report under 

paragraph Ian of this section, the licensee shall paragraph (a)(1) of this section, the licensee shall 

identify: identify: 

(i) The Emergency Class declared; or (i) The Emergency Class declared; or 

(ii) Either paragraph (b)(1), "One-Hour Report," or (ii) Paragraph (b)(1), "One-hour reports," 

paragraph (b)(2) "Four-Hour Report," as the paragraph paragraph (b)(2) "Four-hour reports," or paragraph 

of this section requiring notification of the (b)(3), "Eight-hour reports," as the paragraph of this 

Non-Emergency Event. section requiring notification of the non-emergency 

event. 

§ 50.72(b) Non-emergency events - (1) One- § 50.72(b) Non-emergency events - (1) One

hour reports. If not reported as a declaration of an hour reports. If not reported as a declaration of an 

Emergency Class under paragraph (a) of this section, Emergency Class under paragraph (a) of this section, 

the licensee shall notify the NRC as soon as practical the licensee shall notify the NRC as soon as practical 

and in all cases within one hour of the occurrence of and in all cases within one hour of the occurrence of 

any of the following: 

One-hour report. One-hour report. 

§ 50.72(b)(1)(i)(B) Any deviation from the plant's any deviation from the plant's Technical 

Technical Specifications authorized pursuant to Specifications authorized pursuant to § 50.54(x) of this 

§ 50.54(x) of this part. part. 

One-hour report. Moved to four-hour reports and renumbered (b)(2)(i). 

§ 50.72(b)(1)(ii) The initiation of any nuclear Otherwise unchanged. 

plant shutdown required by the plant's Technical 

Specifications. 

One-hour report. Eight-hour report. 

§ 50.72(b)1)i(ii) Any event or condition durin§ § 50.72(b)L31(ii) Any event or condition that 

operation that results in the condition of the nuclear results in: 

power plant, including its principal safety barriers, LA) The condition of the nuclear power plant, 

being seriously degraded; or results in the nuclear including its principal safety barriers, being seriously 

power plant being: degraded; or 

LA) In an unanalyzed condition that significantly (Bf) The nuclear power plant being in an 

compromises plant safety; unanalyzed condition that significantly degrades plant 

safety. 

(B) In a condition that is outside the design basis Former Items (B) and (C) are deleted. Refer primarily 

of the plant; or to §§: 50.73(a)(2)(i)(B); 50.73(a)(2)(ii)(A) and 

(C) In a condition not covered by the plant's 50.72(b)(3)(ii)(A); 50.73(a)(2)(ii)(B) and 

operating and emergency procedures. 50.72(b)(3)(ii)(B); 50.73(a)(2)(v) and 50.72(b)(3)(v); 

50.73(a)(2)(vii), and; 50.73(a)(2)(ix)(A). 

One-hour report. Deleted. 

§ 50.72(b)(1)(iii) Any natural phenomenon or Refer to Emergency Plan regarding declaration of 

other external condition that poses an actual threat to an Emergency Class. 

the safety of the nuclear power plant or significantly Refer to § 50.73(a)(2)(iii) below regarding LER 

hampers site personnel in the performance of duties requirements. 

necessary for the safe operation of the plant 

One-hour report. Four-hour report. 

§ 50.72(b)(1)(iv) Any event that results or should § 50.72(b)(2)(iv)LA) Any event that results or 

have resulted in Emergency Core Cooling System should have resulted in emergency core cooling 

(ECCS) discharge into the reactor coolant system as a system (ECCS) discharge into the reactor coolant

NUREG-1 022, Rev. 2 10
Changes in Reporting Requirements (continued)

Previous requirements. Amended requirements.

result of a valid signal. system as a result of a valid signal except when the 

actuation results from and is part of a pre-planned 

sequence during testing or reactor operation. 

One-hour report. Eight-hour report. 

§ 50.72(b)fl).(! Any event that results in a major § 50.72(b)(3)(xiii Any event that results in a 

loss of emergency assessment capability, offsite major loss of emergency assessment capability, offsite 

response capability, or communications capability response capability, or offsite communications 

(e.g., significant portion of control room indication, capability (e.g., significant portion of control room 

Emergency Notification System, or offsite notification indication, Emergency Notification System, or offsite 

system). notification system). 

One-hour report. Deleted. 

§ 50.72(b)(1)(vi) Any event that poses an actual Refer to Emergency Plan regarding declaration of 

threat to the safety of the nuclear power plant or an-Emergency Class. 

significantly hampers site personnel in the Refer to § 50.73(a)(2)(x) below regarding LER 

performance of duties necessary for the safe operation requirements. 

of the nuclear power plant including fires, toxic gas 

releases, or radioactive releases. 

§ 50.72(b)(2) Four-hour reports. If not reported Unchanged. 

under paragraphs (a) or (b)(1) of this section, the 

licensee shall notify the NRC as soon as practical and 

in all cases, within four hours of the occurrence of any 

of the following: 

Four-hour report. Eight-hour report. Refer to § 50.72(b)(3)(ii) above, 

§ 50.72(b)2)(i) Any event, found while the reactor which captures these events regardless of whether or 

is shut down, that, had it been found while the reactor not they are found while the reactor is shutdown. 

was in operation, would have resulted in the nuclear 

power plant, including its principal safety barriers, 

being seriously degraded or being in an unanalyzed 

condition that significantly compromises plant safety. 

Four-hour report. Four-hour report. 

§ 50.72(b)(Mii Any event or condition that § 50.72(b)(2)(ivUB) Any event or condition that 

results in a manual or automatic actuation of any results in actuation of the reactor protection system 

engineered safety feature (ESF), including the reactor (RPS) when the reactor is critical except when the 

protection system (RPS), except when: actuation results from and is part of a pre-planned 

(A) The actuation results from and is part of a sequence during testing or reactor operation. 

pre-planned sequence during testing or reactor 

operation; 

Eight-hour report. 

§ 50.72(b)(3)(iv)(A) Any event or condition that 

results in valid actuation of any of the systems listed in 

paragraph (b)(3)(iv)(B) of this section except when the 

actuation results from and is part of a pre-planned 

sequence during testing or reactor operation. 

(B) The actuation is invalid and: (1) Occurs while Former Item (B) is deleted. Invalid actuations, aside 

the system is properly removed from service; from critical scrams, are no longer reportable under 

(2) Occurs after the safety function has been already § 50.72. 

completed; or (3) Involves only the following specific

11 NUREG-1022, Rev. 2
Changes in Reporting Requirements (continued)

Previous requirements. Amended requirements. 

ESFs or their equivalent systems: (i) Reactor water 

clean-up system; (ii) Control room emergency 

ventilation system; (iii) Reactor building ventilation 

system: (iv) Fuel building ventilation system; or 

(v) Auxiliary building ventilation system. 

New paragraph under eight-hour reports. 

§ 50.72(b)(3)(iv)(B) The systems to which the 

requirements of paragraph (b)(3)(iv)(A) of this section 

apply are: 

(1) Reactor protection system (RPS) including: 

reactor scram and reactor trip.5 

(2) General containment isolation signals affecting 

containment isolation valves in more than one system 

or multiple main steam isolation valves (MSIVs). 

(3) Emergency core cooling systems (ECCS) for 

pressurized water reactors (PWRs) including: high

head, intermediate-head, and low-head iniection 

systems and the low pressure injection function of 

residual (decay) heat removal systems. 

(4) ECCS for boiling water reactors (BWRs) 

including: high-pressure and low-pressure core spray 

systems; high-pressure coolant injection system; low 

pressure iniection function of the residual heat removal 

system. 

(5) BWR reactor core isolation cooling system; 

isolation condenser system; and feedwater coolant 

iniection system. 

(6) PWR auxiliary or emergency feedwater 

system. 

(7) Containment heat removal and 

depressurization systems, including containment spray 

and fan cooler systems. 

(8) Emergency ac electrical power systems, 

including: emergency diesel generators (EDGs); 

hydroelectric facilities used in lieu of EDGs at the 

Oconee Station: and BWR dedicated Division 3 EDGs. 

LActuation of the RPS when the reactor is critical 

is reportable under paragraph (b)(2)(iv)(B) of this 

section.

Four-hour report. Eight-hour report. 

§ 50.72(b)(2Wiii) Any event or condition that alone § 50.72(b)(3)(v) Any event or condition that at the 

could have prevented the fulfillment of the safety time of discovery could have prevented the fulfillment 

function of structures or systems that are needed to: of the safety function of structures or systems that are 

(A) Shut down the reactor and maintain it in a safe needed to: 

shutdown condition; (A) Shut down the reactor and maintain it in a safe 

(B) Remove residual heat; shutdown condition; 

(C) Control the release of radioactive material, or (B) Remove residual heat; 

(D) Mitigate the consequences of an accident. (C) Control the release of radioactive material, or 

(D) Mitigate the consequences of an accident. 

New paragraph under eight-hour reports.

NUREG-1022, Rev. 2 12
Changes in Reporting Requirements (continued)

Previous requirements. Amended requirements.

Four-hour report. 

§ 50.72(b)(2)(iv)(A) Any airborne radioactive 

release that, when averaged over a time period of 

1 hour, results in concentrations in an unrestricted 

area that exceed 20 times the applicable concentration 

specified in appendix B to part 20, table 2, column 1. 

(B) Any liquid effluent release that, when 

averaged over a time of 1 hour, exceeds 20 times the

anolicable concentration soecified in aDoendix B to

part 20, table 2, column 2, at the point of entry into the 

receiving waters (i.e., unrestricted area) for all 

radionuclides except tritium and dissolved noble 

gases. (Immediate notifications made under this 

paragraph also satisfy the requirements of § 20.2202 

of this chapter.)

§ 50.72(b)(3)(vi) Events covered in paragraph 

(b)(3)(v) of this section may include one or more 

procedural errors, equipment failures, and/or discovery 

of design, analysis, fabrication, construction, and/or 

procedural inadequacies. However, individual 

comoonent failures need not be reDorted Dursuant to

paragraph (b)(3)(v) of this section if redundant

eauioment in the same system was ooerable and

available to perform the required safety function.

Deleted. 

Refer to Emergency Plan regarding declaration of 

an Emergency Class. 

Refer to § 50.72(b)(2)(xi) below regarding a news 

release or notification of another agency. 

Refer to § 20.2202 regarding events reportable 

under that section. 

Refer to § 50.73(a)(2)(viii) below regarding LER 

requirements.

Four-hour report. Moved to eight-hour reports and renumbered 

§ 50.72(b)f2)_(_ Any event requiring the transport (b)L()xij. Otherwise unchanged. 

of a radioactively contaminated person to an offsite 

medical facility for treatment. 

Four-hour report. Four-hour report. Renumbered (b)(2). Otherwise 

§ 50.72(b)(2)(vi) Any event or situation, related to unchanged. 

the health and safety of the public or onsite personnel, 

or protection of the environment, for which a news 

release is planned or notification to other government 

agencies has been or will be made. Such an event 

may include an onsite fatality or inadvertent release of 

radioactively contaminated materials. 

Four-hour report. Deleted. Refer to § 72.216 below, which captures 

§ 50.72(b)(2)(vii) Any instance of: these events. 

(A) A defect in any spent fuel storage cask 

structure, system, or component which is important to 

safety; or 

(B) A significant reduction in the effectiveness of 

any spent fuel storage cask confinement system 

during use of the storage cask under a general license 

issued under § 72.210 of this chapter. 

A followup written report is required by § 72.216(b) of 

this chapter including a description of the means 

employed to repair any defects or damage and prevent 

recurrence, using instructions in § 72.4, within 30 days 

of the report submitted in paragraph (a). A copy of the

13 NUREG-1022, Rev. 2
Changes in Reporting Requirements (continued)

Previous requirements.

written report must be sent to the administrator of the 

appropriate Nuclear Regulatory Commission regional 

^f oi- ýh,^n in •nnrndiiv n- +n n~rt 9n o-f this r-hntor

§ 50.72(c) Followup notification. With respect to the 

telephone notifications made under paragraphs (a) 

and (b) of this section, in addition to making the 

required initial notification, each licensee, shall during 

the course of the event: 

(1) Immediately report (i) any further degradation 

in the level of safety of the plant or other worsening 

plant conditions, including those that require the 

declaration of any of the Emergency Classes, if such a 

declaration has not been previously made, or 

(ii) any change from one Emergency Class to 

another, or 

(iii) a termination of the Emergency Class. 

(2) Immediately report (i) the results of ensuing 

evaluations or assessments of plant conditions, 

(ii) the effectiveness of response or protective 

measures taken, and 

(iii) information related to plant behavior that is 

not understood. 

(3) Maintain an open, continuous communication 

channel with the NRC Operations Center upon request 

by the NRC.

Amended requirements. T

Unchanged.

§ 50.73 Licensee event report system.

§ 50.73(a) Reportable events. (1) The holder of 

an operating license for a nuclear power plant 

(licensee) shall submit a Licensee Event Report (LER) 

for any event of the type described in this paragraph 

within 30 days after the discovery of the event. Unless 

otherwise specified in this section, the licensee shall 

report an event regardless of the plant mode or power 

level, and regardless of the significance of the 

structure, system, or component that initiated the 

event.

§ 50.73(a) Reportable events. (1) The holder of 

an operating license for a nuclear power plant 

(licensee) shall submit a Licensee Event Report (LER) 

for any event of the type described in this paragraph 

within 60 days after the discovery of the event. In the 

case of an invalid actuation reported under 

§ 50.73(a)(2)(iv), other than actuation of the reactor 

protection system (RPS) when the reactor is critical,

the licensee may. at its option. provide a telephone

notification to the NRC Operations Center within 60 

days after discovery of the event instead of submitting 

a written LER. Unless otherwise specified in this 

section, the licensee shall report an event if it occurred 

within three years of the date of discovery regardless 

of the plant mode or power level, and regardless of the 

significance of the structure, system, or component 

that initiated the event.

§ 50.73(a)(2) The licensee shall report: (i)(A) Unchanged. 

The completion of any nuclear plant shutdown 

required by the plant's Technical Specifications; or 

§ 50.73(a)(2)(i)(B) Any operation or condition § 50.73(a)(2)(i)(B) Any operation or condition

NUREG-1022, Rev. 2

týF- bt I

14
Changes in Reporting Requirements (continued)

Previous requirements. Amended requirements.

prohibited by the plant's Technical Specifications; or

§ 50.73(a)(2)(i)(C) Any deviation from the plant's 

Technical Specifications authorized pursuant to 

§ 50.54(x) of this part.

§ 50.73(a)(2)(ii) Any event or condition that 

resulted in 

the condition of the nuclear power plant, including its 

principal safety barriers, being seriously degraded, or 

that resulted in 

the nuclear power plant being: 

(A) In an unanalyzed condition that significantly 

compromised plant safety; 

(B) In a condition that was outside the design 

basis of the plant: or 

(C) In a condition not covered by the plant's 

operating and emergqency procedures.

§ 50.73(a)(2)(iii) Any natural phenomenon or 

other extemal condition that posed an actual threat to 

the safety of the nuclear power plant or significantly 

hampered site personnel in the performance of duties 

necessary for the safe operation of the nuclear power 

plant.

§ 50.73(a)(2)(iv) Any event or condition that 

resulted in a manual or automatic actuation of any ennineered .•fe.tv f•.t~rim (ESFV includincz the reactor

protection system (RPS) 

except when: 

(A) The actuation resulted from and was part of a 

pre-planned sequence during testing or reactor 

operation; 

(B) The actuation was invalid and; 

(1) Occurred while the system was properly 

removed from service; 

(2) Occurred after the safety function had been 

already completed; or

which was prohibited by the plant's Technical 

Specifications except when: 

(1) The Technical Specification is administrative 

in nature; 

(2) The event consisted solely of a case of a late 

surveillance test where the oversiaht was corrected.

the test was performed, and the eauipment was found

to be capable of performing its specified safety 

functions or 

(3) The Technical Specification was revised prior 

to discovery of the event such that the operation or

condition was no longer prohibited at the time of 

discovery of the event.

Unchanged.

§ 50.73(a)(2)(ii) Any event or condition that 

resulted in: 

(A) The condition of the nuclear power plant, 

including its principal safety barriers, being seriously 

degraded; or 

(B) The nuclear power plant being in an 

unanalyzed condition that significantly de-graded plant 

safety. 

Former Items (B) and (C) are deleted. Refer primarily 

to §§ 50.73(a)(2)(i)(B), (a)(2)(ii)(A), (a)(2)(ii)(B), 

(a)(2)(v), (a)(2)(vii), and (a)(2)(ix)(A).

Unchanged.

§ 50.73(a)(2)(iv)LA) Any event or condition that 

resulted in manual or automatic actuation of any of the 

systems listed in paragraph (a)(2)(iv)(B) of this 

section, 

except when: 

(1) The actuation resulted from and was part of a 

pre-planned sequence during testing or reactor 

operation; or 

(2) The actuation was invalid and; 

(i) Occurred while the system was properly 

removed from service; or 

(ii) Occurred after the safety function had been 

already completed.

NUREG-1022, Rev. 2

enninee/ .... ... ... fe.. ... I--SR in ..... lu .. n rea..... ...

15
Changes in Reporting Requirements (continued)

Amended requirements.

(3) Involved only the following specific ESFs or Former Item (3) is deleted. Actuations of these 

their equivalent systems: systems are no longer reportable under § 50.73. 

(i) Reactor water clean-up system; 

(ii) Control room emerqency ventilation system; 

(iii) Reactor building ventilation system; 

(iv) Fuel buildinq ventilation system; or 

(v) Auxiliary building ventilation.

§ 50.73(a)(2)(v) Any event or condition that alone 

could have prevented the fulfillment of the safety 

function of structures or systems that are needed to: 

(A) Shut down the reactor and maintain it in a safe 

shutdown condition; 

(B) Remove residual heat; 

(C) Control the release of radioactive material; or 

(D) Mitigate the consequences of an accident.

§ 50.73(a)(2)(vi) Events covered in paragraph 

(a)(2)(v) of this section may include one or more 

procedural errors, equipment failures, and/or discovery

New paragraph. 

§ 50.73(a)(2)(iv)(B) The systems to which the 

requirements of paragraph (a)(2)(iv)(A) of this section 

apply are: 

(1) Reactor protection system (RPS) including: 

reactor scram or reactor trip. 

(2) General containment isolation signals affecting 

containment isolation valves in more than one system

or multiole main steam isolation valves (MSIVsV.

(3) Emercgencv core coolina systems (ECCS) for

oressurized water reactors (PWRs) includina: hiahhead, intermediate-head, and low-head injection 

systems and the low pressure iniection function of 

residual (decay) heat removal systems.

(4) ECCS for boiling water reactors (BWRs)

including: high-pressure and low-pressure core spray 

systems: high-pressure coolant injection system: low 

pressure iniection function of the residual heat removal 

system. 

(5) BWR reactor core isolation cooling system: 

isolation condenser system: and feedwater coolant

injection system. 

(6) PWR auxiliary or emergencv feedwater

system. 

(7) Containment heat removal and

deoressurization systems. includino containment sorav

and fan cooler systems. 

(8) Emergency ac electrical power systems, 

including: emergency diesel generators (EDGs);

hydroelectric facilities used in lieu of EDGs at the

Oconee Station; and BWR dedicated Division 3 EDGs. 

(9) Emeraencv service water systems that do not

normally run and that serve as ultimate heat sinks.

§ 50.73(a)(2)(v) Any event or condition that 

could have prevented the fulfillment of the safety 

function of structures or systems that are needed to: 

(A) Shut down the reactor and maintain it in a safe 

shutdown condition; 

(B) Remove residual heat; 

(C) Control the release of radioactive material; or 

(D) Mitigate the consequences of an accident.

§ 50.73(a)(2)(vi) Events covered in paragraph 

(a)(2)(v) of this section may include one or more 

procedural errors, equipment failures, and/or discovery

NUREG-1022, Rev. 2

Previous requirements.

16
Changes in Reporting Requirements (continued)

Previous requirements. Amended requirements.

of design, analysis, fabrication, construction, and/or 

procedural inadequacies. However, individual 

component failures need not be reported pursuant to 

this paragraph if redundant equipment in the same 

system was operable and available to perform the 

required safety function.

§ 50.73(a)(2)(vii) Any event where a single cause 

or condition caused at least one independent train or 

channel to become inoperable in multiple systems or 

two independent trains or channels to become 

inoperable in a single system designed to: 

(A) Shut down the reactor and maintain it in a safe 

shutdown condition; 

(B) Remove residual heat; 

(C) Control the release of radioactive material; or 

(D) Mitigate the consequences of an accident.

§ 50.73(a)(2)(viii)(A) Any airborne radioactive 

release that, when averaged over a time period of 1 

hour, resulted in airborne radionuclide concentrations 

in an unrestricted area that exceeded 20 times the 

applicable concentration limits specified in appendix B 

to part 20, table 2, column 1. 

(B) Any liquid effluent release that, when 

averaged over a time period of 1 hour, exceeds 20 

times the applicable concentrations specified in 

appendix B to part 20, table 2, column 2, at the point 

of entry into the receiving waters (i.e., unrestricted 

area) for all radionuclides except tritium and dissolved 

noble gases.

§ 50.73(a)(2)(ix) Reports submitted to the 

Commission in accordance with paragraph (a)(2)(viii) 

of this section also meet the effluent release reporting 

requirements of § 20.2203(a)(3) of this chapter.

of design, analysis, fabrication, construction, and/or 

procedural inadequacies. However, individual 

component failures need not be reported pursuant to 

paragraph (a)(2)(v) of this section if redundant 

equipment in the same system was operable and 

available to perform the required safety function.

Unchanged.

Unchanged.

Deleted. Refer to § 20.2203(a)(3) regarding reports 

required under that paragraph.

*I.

New requirement. 

4 50.73(a)(2)(ix)(A) Any event or condition that as 

q rpiJlt nf A qinnlp cmpj. could have nrevented the

fulfillment of a safety function for two or more trains or 

channels in different systems that are needed to: 

(1) Shut down the reactor and maintain it in a safe 

shutdown condition; 

(2) Remove residual heat; 

(3) Control the release of radioactive material; or

(4) Mitigate the consequences of an accident. 

§ 50.73(a)(2)(ix)(B) Events covered in paragraph 

(ix)(A) of this section may include cases of procedural 

error, equipment failure, and/or discovery of a design, 

analysis, fabrication, construction, and/or procedural 

inadequacy. However, licensees are not required to 

refort an event npIrsant t•n naranrpnh (fixIAA nf thik

_____________________________ 1 2 1,..,..,. . .

17 NUREG-1022, Rev. 2
Changes in Reporting Requirements (continued)

Previous requirements.

§ 50.73(a)(2)(x) Any event that posed an actual 

threat to the safety of the nuclear power plant or 

significantly hampered site personnel in the 

performance of duties necessary for the safe operation 

of the nuclear power plant including fires, toxic gas 

releases, or radioactive releases.

§ 50.73(b), Contents. The Licensee Event Report 

shall contain: 

§ 50.73(b)(1) A brief abstract describing the major 

occurrences during the event, including all component 

or system failures that contributed to the event and 

significant corrective action taken or planned to 

prevent recurrence. 

§ 50.73(b)(2)(i) A clear, specific, narrative 

description of what occurred so that knowledgeable 

readers conversant with the design of commercial 

nuclear power plants, but not familiar with the details 

of a particular plant, can understand the complete 

event. 

§ 50.73(b)(2)(ii) The narrative description must 

include the following specific information as 

appropriate for the particular event: 

§ 50.73(b)(2)(ii)(A) Plant operating conditions 

before the event. 

§ 50.73(b)(2)(ii)(B) Status of structures, 

components, or systems that were inoperable at the 

start of the event and that contributed to the event. 

§ 50.73(b)(2)(ii)(C) Dates and approximate times 

of occurrences. 

§ 50.73(b)(2)(ii)(D) The cause of each component 

or system failure or personnel error, if known. 

§ 50.73(b)(2)(ii)(E) The failure mode, mechanism, 

and effect of each failed component, if known.

§ 50.73(b)(2)(ii)(F) The Energy Industry 

Identification System component function identifier 

and system name of each component or system 

referred to in the LER. 

(1) The Energy Industry Identification System is 

defined in: IEEE Std 803-1983 (May 16,1983) 

Recommended Practices for Unique Identification 

Plants and Related Facilities--Principles and 

Definitions. 

(2) IEEE Std 803-1983 has been approved for 

incorporation by reference by the Director of the 

Federal Register. 

A notice of any changes made to the material

Amended requirements. 1*

4-

-1-

section if the event results from:

(1) A shared dependency among trains or 

channels that is a natural or expected consequence o 

the approved Dlant desian, or

jOMannal o nil ovnar.torl ,naor nr Manro,+stir.n 10~ K I 1 11⁄4 144 . +t 1ia. 4 .IL~ 14 4I +;4LJ,

Unchanged.

Unchanged.

§ 50.73(b)(2)(ii)(F) The Energy Industry 

Identification System component function identifier 

and system name of each component or system 

referred to in the LER. 

(1) The Energy Industry Identification System is 

defined in: IEEE Std 803-1983 (May 16,1983) 

Recommended Practice for Unique Identification in 

Power Plants and Related Facilities--Principles and 

Definitions. 

(2) IEEE Std 803-1983 has been approved for 

incorporation by reference by the Director of the 

Federal Register. 

(3) A notice of any changes made to the material

NUREG-1022, Rev. 2 18
Changes in Reporting Requirements (continued)

Previous requirements. Amended requirements.

incorporated by reference will be published in the 

Federal Register. Copies may be obtained from the 

Institute of Electrical and Electronics Engineers, 345 

East 47th Street, New York, NY 10017. IEEE Std 

803-1983 is available for inspection at the NRC's 

Technical Library, which is located at 11545 Rockville 

Pike, Rockville, Maryland 20852 - 2738; and at the 

Office of the Federal Register, 800 North Capitol 

Street, NW., Suite 700, Washinqton. DC.

incorporated by reference will be published in the 

Federal Register. Copies may be obtained from the 

Institute of Electrical and Electronics Engineers, 345 

East 47th Street, New York, NY 10017. IEEE Std 

803-1983 is available for inspection at the NRC's 

Technical Library, which is located in the Two White 

Flint North Building, 11545 Rockville Pike, Rockville, 

Maryland; and at the Office of the Federal Register, 

1100 L Street. NW. Washinaton. DC.

§ 50.73(b)(2)(ii)(G) For failures of components Unchanged. 

with multiple functions, include a list of systems or 

secondary functions that were also affected. 

§ 50.73(b)(2)(ii)(H) For failure that rendered a 

train of a safety system inoperable, an estimate of the 

elapsed time from the discovery of the failure until the 

train was returned to service. 

§ 50.73(b)(2)(ii)(I) The method of discovery of 

each component or system failure or procedural error. 

§ 50.73(b)(2)(ii)(J)(1) Operator actions that § 50.73(b)(2)(ii)(J) For each human performance 

affected the course of the event, including operator related root cause, the licensee shall discuss the 

errors, procedural deficiencies, or both, that cause(s) and circumstances. 

contributed to the event. 

(2) For each personnel error, the licensee shall 

discuss: 

(i) Whether the error was a cognitive error (e.g., 

failure to recognize the actual plant condition, failure to 

realize which systems should be functioning, failure to 

recognize the true nature of the event) or a procedural error: 

(ii) Whether the error was contrary to an approved 

procedure, was a direct result of an error in an 

approved procedure, or was associated with an activity 

or task that was not covered by an approved 

procedure. 

(iii) Any unusual characteristics of the work 

location (e.g., heat, noise) that directly contributed to 

the error; and 

(iv) The type of personnel involved (i.e., contractor 

personnel, utility-licensed operator, utility nonlicensed 

operator, other utility personnel). 

§ 50.73(b)(2)(ii)(K) Automatically and manually Unchanged. 

initiated safety system responses. 

§ 50.73(b)(2)(ii)(L) The manufacturer and model 

number (or other identification) of each component 

that failed during the event. 

§ 50.73(b)(3) An assessment of the safety § 50.73(b)(3) An assessment of the safety 

consequences and implications of the event. This consequences and implications of the event. This 

assessment must include the availability of other assessment must include: 

systems or components that could have performed the _(j) The availability of systems or components that 

same function as the components and systems that could have performed the same function as the

19 NUREG-1022, Rev. 2
Changes in Reporting Requirements (continued)

Previous requirements. Amended requirements.

failed during the event, components and systems that failed during the event, 

and 

(ii) For events that occurred when the reactor was 

shutdown, the availability of systems or components 

that are needed to shutdown the reactor and maintain 

safe shutdown conditions, remove residual heat, 

control the release of radioactive material, or mitigate 

the consequences of an accident. 

§ 50.73(b)(4) A description of any corrective Unchanged. 

actions planned as a result of the event, including 

those to reduce the probability of similar events 

occurring in the future. 

§ 50.73(b)(5) Reference to any previous similar 

events at the same plant that are known to the 

licensee. 

§ 50.73(b)(6) The name and telephone number of 

a person within the licensee's organization who is 

knowledgeable about the event and can provide 

additional information concerning the event and the 

plant's characteristics. 

§ 50.73(c) Supplemental information. The Unchanged. 

Commission may require the licensee to submit 

specific additional information beyond that required by 

paragraph (b) of this section if the Commission finds 

that supplemental material is necessary for complete 

understanding of an unusually complex or significant 

event. These requests for supplemental information 

will be made in writing and the licensee shall submit, 

as specified in § 50.4, the requested information as a 

supplement to the initial LER. 

§ 50.73(d) Submission of reports. Licensee § 50.73(d) Submission of reports. Licensee 

Event Reports must be prepared on Form NRC 366 Event Reports must be prepared on Form NRC 366 

and submitted within 30 days of discovery of a and submitted to the U.S. Nuclear Regulatory 

reportable event or situation to the U.S. Nuclear Commission, as specified in § 50.4. 

Regulatory Commission, as specified in § 50.4. 

§ 50.73(e) Report legibility. The reports and Unchanged. 

copies that licensees are required to submit to the 

Commission under the provisions of this section must 

be of sufficient quality to permit legible reproduction 

and micrographic processing. 

§ 50.73(f) Exemptions. Upon written request Deleted. Refer to § 50.12 regarding exemptions. 

from a licensee including adequate justification or at 

the initiation of the NRC staff, the NRC Executive 

Director for Operations may, by a letter to the licensee, 

grant exemptions to the reporting requirements under 

this section. 

§ 50.73(g) Reportable occurrences. The Unchanged. 

requirements contained in this section replace all

NUREG-1022, Rev. 2 20
Changes in Reporting Requirements (continued)

Previous requirements. Amended requirements.

NUREG-1022, Rev. 2

existing requirements for licensees to report 

"Reportable Occurrences" as defined in individual 

plant Technical Specifications. 

§72.216 Reports. 

§ 72.216(a) The general licensee shall make an § 72.216(a) JReserved.1 

initial report under F 50.72(b)(2)(vii) of this chapter of 

any: 

(1) Defect discovered in any spent fuel storage 

cask structure, system, or component which is 

important to safety; or 

(2) Instance in which there is a significant 

reduction in the effectiveness of any spent fuel storage 

cask confinement system during use. 

§ 72.216(b) A written report, including a § 72.216(b) [Reserved.1 

description of the means employed to repair any 

defects or damage and prevent recurrence, must be 

submitted using instructions in 4 72.4 within 30 days 

of the report submitted in paragraph (a) of this section. 

A copy of the written report must be sent to the 

administrator of the appropriate Nuclear Regulatory 

Commission regional office shown in appendix D to 

part 20 of this chapter. 

§ 72.216(c) The general licensee shall make initial § 72.216(c) The general licensee shall make initial 

and written reports in accordance with Secs. 72.74 and written reports in accordance with § 72.74 and 

and 72.75, except for the events specified by Sec. 72.75. 

72.75(b)(2) and (3) for which the initial reports will be 

made under paragraph (a) of this section. 

Sections 72.74 and 72.75 are unchanged. They capture the reports discussed in the former 

§§ 72.216(a) and 72.216(b) above, as well as a number of other reports.

21
2 REPORTING AREAS WARRANTING SPECIAL MENTION

This section clarifies specific areas that are applicable to multiple reporting criteria or that 

historically appear to be subject to varied interpretations. 

2.1 Engineering Judgment 

The reportability of many events and conditions is self evident. However, the reportability of 

other events and conditions may not be readily apparent and the use of engineering judgment 

is involved in determining reportability. 

Engineering judgment may include either a documented engineering analysis or a judgment by 

a technically qualified individual, depending on the complexity, seriousness, and nature of the 

event or condition. A documented engineering analysis is not a requirement for all events or 

conditions, but it would be appropriate for particularly complex situations. In addition, although 

not required by the rule, it may be prudent to record in writing that a judgment was exercised 

by identifying the individual making the judgment, the date made, and briefly documenting the 

basis for this judgment. In any case, the staff considers that the use of engineering judgment 

implies a logical thought process that supports the judgment. 

2.2 Differences in Tense Between 10 CFR 50.72 and 50.73 

The present tense is generally used in 10 CFR 50.72 because the event or condition generally 

would be ongoing at the time of reporting. The past tense is used in 10 CFR 50.73 because 

the event or condition is generally past when an LER is written. Where the tense is relevant to 

reportability, it is addressed under the specific criterion in Section 3 of this report. 

2.3 Reporting Multiple Events in a Single Report 

More than one failure or event may be reported in a single ENS notification or LER if (1) the 

failures or events are related (i.e., they have the same general cause or consequences) and 

(2) they occurred during a single activity (e.g., a test program) over a reasonably short time 

(e.g., within 4 hours or 8 hours for ENS notifications, or within 60 days LER reporting). 

To the extent feasible, report failures that occurred within the first 60 days of discovery of the 

first failure on one LER. If appropriate, state in the LER text that a supplement to the LER will 

be submitted when the test program is completed. In the revised LER, include all the failures, 

including those reported in the original LER (i.e., the revised LER should stand alone). 

Generally, LERs are intended to address specific events and plant conditions. Thus, unrelated 

events or conditions should not be reported in one LER. Also, an LER revision should not be

23 NUREG-1022, Rev. 2
used to report subsequent failures of the same or like components that are the result of a 

different cause or for separate events or activities. 

Unrelated failures or events should be reported as separate ENS notifications to be given 

unique ENS numbers by the NRC. However, multiple ENS notifications may be addressed in a 

single telephone call. 

2.4 Deficiencies Discovered During Engineering Reviews or Inspections 

As indicated in NUREG-1397, "An Assessment of Design Control Practices and Design 

Reconstitution Programs in the Nuclear Power Industry," February 1991, Section 4.3.2, the 

reporting requirements specified in 10 CFR 50.9, 50.72, and 50.73 apply equally to 

discrepancies discovered during design document reconstitution (DDR) programs, design

bases documentation reviews (DBDRs), and other similar engineering reviews. There is no 

basis for treating discrepancies discovered during such reviews differently from any other 

reportable item. 

Licensees should evaluate the reportability of suspected but unsubstantiated discrepancies 

discovered during such a review program in the same manner as other potentially reportable 

items. See Section 2.5 for discussion of reporting time limits and discovery dates. 

2.5 Time Limits for Reporting 

Reporting times in 10 CFR 50.72 are keyed to the occurrence of the event or condition, as 

described below. 

Section 50.72(a)(3) requires ENS notification of the declaration of an Emergency Class 

"...immediately after notification of the appropriate State or local agencies and not later 

than one hour after the time the licensee declares one of the Emergency Classes." 

Section 50.72(b)(1) requires ENS notification for specific types of events and --ndition

one type of event "...as soon as practical and in all cases within one hour of the 

occurrence of any deviation from the plant's technical specifications authorized ...... 

Section 50.72(b)(2) requires ENS notification for specific types of events and conditions 

as soon as practical and in all cases, within four hours of the occurrence of any of the 

following: ...... 

Section 50.72(b)(3) requires ENS notification for specific types of events and conditions 

as soon as practical and in all cases, within foetr-eiiht hours of the occurrence of any of the 

following: 

These 10 CFR 50.72 reporting times have some flexibility because a licensee needs to ensure 

that reporting does not interfere with plant operation. However, that does not mean that a 

licensee should automatically wait until close to the time limit expiration before reportinq. 

For the case of an event for which a news release is planned, as reported under 10 CFR 

50.72(b)(2)(xi), the purpose of the report is to provide timely and accurate information so the

NUREG-1022, Rev. 2 24
NRC can respond to heightened public concern. Accordingly, it makes sense to provide the 

report by the time the news release is issued. 

Section 50.73 requires submittal of an LER "within -3-60 days after the discovery" of a 

reportable event. Many reportable events are discovered when they occur. However, if the 

event is discovered at some later time, the discovery date is when the reportability clock starts 

under 10 CFR 50.73. 

Discovery date is generally the date when the event was discovered rather than the date when 

an evaluation of the event is completed. For example, if a technician sees a problem, but a 

delay occurs before an engineer or supervisor has a chance to review the situation, the 

discovery date (which starts the 60-day clock) is the date that the technician sees a problem. 

However, in some cases, such as discovery of an existing but previously unrecognized 

condition, it may be necessary to undertake an evaluation in order to determine if an event or 

condition is reportable. If so, the guidance provided in Generic Letter 91-18, "Information to 

Licensees Regarding two NRC Inspection Manual Sections on Resolution of Degraded and 

Nonconforming Conditions and on Operability," which applies primarily to operability 

determinations, is appropriate for reportability determinations as well. This guidance indicates 

that the evaluation should proceed on a time scale commensurate with the safety significance 

of the issue and, whenever reasonable expectation that the equipment in question is operable 

no longer exists, or significant doubts begin to arise, appropriate actions, including reporting, 

should be taken. 

2.6 Events Discussed with the NRC Staff 

On occasion, some licensee personnel have erroneously believed that if a reportable event or 

condition had been discussed with the resident inspector or other NRC staff, there was no 

need to report under 10 CFR 50.72 and 50.73 because the NRC was aware of the situation. 

Some licensee personnel have also expressed a similar misunderstanding for cases in which 

the NRC staff identified a reportable event or condition to the licensee via inspection or 

assessment activities. Such conditions do not satisfy §§ 50.72 and 50.73. Sections 50.72 and 

50.73 specifically require a telephone notification via the ENS and/or submittal of a written LER 

for an event or condition that meets the criteria stated in those rules. 

2.7 Voluntary Reporting 

Information that does not meet the reporting criteria of 10 CFR 50.72 and 50.73 may be 

reportable under other requirements such as 10 CFR 50.9, 20.2202, 20.2203, 50.36, 72.74, 

72.216, 73.71, and Part 21. In particular, 10 CFR 50.9 (b) states "Each applicant or licensee 

shall notify the Commission of information identified by the applicant or licensee as having for 

the regulated activity a significant implication for public health and safety or common defense 

and security." This applies to information which is not already required by other reporting or 

updating requirements. Notification must be made to the Administrator of the appropriate 

Regional Office within two working days of identifying the information. Reporting pursuant to

25 NUREG-1 022, Rev. 2
§ 50.9 is required, not voluntary.1 Voluntary reporting, as discussed in the following 

paragraphs, pertains to information of lesser significance than described in § 50.9(b). 

Licensees are permitted and encouraged to report any event or condition that does not meet 

the criteria for required reporting, if the licensee believes that the event or condition might be of 

safety significance or of generic interest or concern. Reporting requirements aside, assurance 

of safe operation of all plants depends on accurate and complete reporting by each licensee of 

all events having potential safety significance. Instructions for voluntary ENS notifications and 

LERs are discussed in Sections 4.2.2 and 5.1.5 of this report. 

The NRC staff encourages voluntary LERs rather than information letters for voluntary 

reporting. The LER format is preferable because it provides the information needed to support 

NRC review of the event and facilitates administrative processing, including data entry. 

2.8 Retraction or Cancellation of Event Reports 

An ENS notification may be retracted via a follow-up telephone call, as discussed further in 

Section 4.2.3 of this report. A retracted ENS report is retained in the ENS data base, along 

with the retraction. 

An LER may be canceled by letter as discussed further in Section 5.1.2 of this report. 

Canceled LERs are deleted from the LER data base. 

Sound, logical bases for the withdrawal should be communicated with the retraction or 

cancellation. (Example 3 in Section 3.2.4 illustrates a case where there were sound reasons 

for a retraction. The last event under Example 1 in Section 3.2.6 illustrates a case where the 

reasons for retraction were not adequate.) 

'As indicated in the Statement of Considerations for § 50.9, "A licensee cannot evade the rule by never 

'finding' information to be significant. The fact that a licensee considers information to be significant can be 

established, for example, by the actions taken by the licensee to evaluate that information." 59 FR 49362, 

December 31, 1987.

NUREG-1022, Rev. 2 26
3 SPECIFIC REPORTING GUIDELINES

3.1 General Requirements 

3.1.1 Immediate Notifications

§ 50.72(a) General Requirements1 

"(1) Each nuclear power reactor licensee licensed under 

§ 50.21 (b) or § 50.22 of this part shall notify the NRC 

Operations Center via the Emergency Notification System 

of: 

(i) The declaration of any of the Emergency Classes 

specified in the licensee's approved Emergency Plan;2 or 

(ii) Those non-emergency events specified in paragraph 

(b) of this section that occurred within three years of the 

date of discovery. 

(2) If the Emergency Notification System is inoperative, 

the licensee shall make the required notifications via 

commercial telephone service, other dedicated telephone 

system, or any other method which will ensure that a report 

is made as soon as practical to the NRC Operations 

Center.3 

(3) The licensee shall notify the NRC immediately after 

notification of the appropriate State or local agencies and 

not later than one hour after the time the licensee declares 

one of the Emergency Classes. 

(4) The licensee shall activate the Emergency 

Response Data System (ERDS)5 as soon as possible but 

not later than one hour after declaring an Emergency Class 

of alert, site area emergency, or general emergency. The 

ERDS may also be activated by the licensee during 

emergency drills or exercises if the licensee's computer 

system has the capability to transmit the exercise data. 

(5) When making a report under paragraph La(1) of this 

section, the licensee shall identify: 

(i) The Emergency Class declared; or 

(ii) Paragraph (b)(1), 'One-hour 

reports,' paragraph (b)(2) 'Four-hour reports,' or paragraph 

(b)(3), 'Eiqht-hour reports,' as the paraqraph of this section

§ 50.73 

There is no requirement 

in § 50. 73 to report the 

declaration of an 

Emergency Class. 

However, an event or 

condition that leads to 

declaration of an 

Emergency Class may meet 

one or more of the specific 

reporting requirements that 

are in § 50.73. 

There is usually a 

parallel reporting 

requirement in § 50.73 that 

captures a non-emergency 

event that is reportable 

under § 50.72. Exceptions 

are: a press release; 

notification to another 

government agency; 

transport of a contaminated 

person offsite; and loss of 

emergency preparedness 

capability.

27 NUREG-1022, Rev. 2

I
Discussion 

Appendix E to 10 CFR Part 50, Section IV (C), "Activation of Emergency Organization," 

establishes four emergency classes for nuclear power plants: Notification of Unusual Event, 

Alert, Site Area Emergency, and General Emergency. NUREG-0654/FEMA-REP-1, Revision 

1, "Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and 

Preparedness in Support of Nuclear Power Plants" (March 1987), and more recently, 

NUMARC/NESP-007, Revision 2, "Methodology for Development of Emergency Action Levels" 

(January 1992), provide the basis for these emergency classes and numerous examples of the 

events and conditions typical of each emergency class. Licensees use this guidance in 

preparing their emergency plans. Use of these four emergency class terms in the ENS 

notification help the NRC recognize the significance of an emergency. Time frames specified 

for notification in § 50.72(a) use the words "immediately" and "not later than one hour" to 

ensure the Commission can fulfill its responsibilities during and following the most serious 

events. 

Occasionally, a licensee discovers that a condition existed which met the emergency plan 

criteria but no emergency was declared and the basis for the emergency class no longer exists 

at the time of this discovery. This may be due to a rapidly concluded event or an oversight in 

the emergency classification made during the event or it may be determined during a post

event review. Frequently, in cases of this nature, which were discovered after the fact, 

licensees have declared the emergency class, immediately terminated the emergency class 

and then made the appropriate notifications. However, the NRC staff does not consider actual 

declaration of the emergency class to be necessary in these circumstances; an ENS 

notification (or an ENS update if the event was previously reported but mis-classified) within 

one hour of the discovery of the undeclared (or mis-classified) event provides an acceptable 

alternative.2 

2 Notification of the State and local emergency response organizations should be made in accordance 

with the arrangements made between the licensee and offsite organizations.

NUREG-1022, Rev. 2

requiring notification of the non-emergency event." 

' Other requirements for immediate notification of the 

NRC by licensed operating nuclear power reactors are 

contained elsewhere in this chapter, in particular, 

§§ 20.1906, 20.2202, 50.36, 72.216 and 73.71. 

2These Emergency Classes are addressed in Appendix E 

of this part. 

' Commercial telephone number of the NRC Operations 

Center is (301) 816-5100." 

4 Requirements for ERDS are addressed in Appendix E, 

Section VI.

28
3.1.2 Licensee Event Reports

§ 50.72 

There is no comparable 

passage in § 50.72.

§ 50.73(a)(1) 

"The holder of an operating license for a nuclear power 

plant (licensee) shall submit a Licensee Event Report 

(LER) for any event of the type described in this paragraph 

within 60 days after the discovery of the event. In the 

case of an invalid actuation reported under 

§ 50.73(a)(2)(iv), other than actuation of the reactor 

protection system (RPS) when the reactor is critical, the 

licensee may, at its option, provide a telephone notification

to the NRC ODerations Center within 60 days after

discovery of the event instead of submitting a written LER. 

Unless otherwise specified in this section, the licensee 

shall report an event if it occurred within three years of the 

date of discovery regardless of the plant mode or power 

level, and regardless of the significance of the structure, 

system, or component that initiated the event."

Discussion 

Unless otherwise specified, this part of the rule requires reporting of an event if it occurred 

within three years prior to discovery regardless of the plant mode or power level and 

regardless of the significance of the structure, system, or component that initiated the event. 

In the case of an invalid actuation reported under section 50.73(a)(2)(iv) the licensee may, at 

its option, provide a telephone notification to the NRC Operations Center within 60 days after 

discovery of the event instead of submitting a written LER. 

3.2 Specific Reporting Criteria 

3.2.1 Plant Shutdown Required by Technical Specifications 

§ 50.72(b)(2)(i) § 50.73(a)(2)(i)(A) 

"The initiation of any nuclear plant "The completion of any nuclear plant 

shutdown required by the plant's Technical shutdown required by the plant's Technical 

Specifications." ' Specifications; or" 

If not reported under § 50.72(a) or (b)(1), an ENS notification is required. If the shutdown is 

completed, an LER is required.

29 NUREG-1022, Rev. 2
Discussion

The § 50.72 reporting requirement is intended to capture those events for which TS require the 

initiation of reactor shutdown to provide the NRC with early warning of safety significant 

conditions serious enough to warrant that the plant be shut down. 

For § 50.72 reporting purposes, the phrase "initiation of any nuclear plant shutdown" includes 

action to start reducing reactor power, i.e., adding negative reactivity to achieve a nuclear plant 

shutdown required by TS. This includes initiation of any shutdown due to expected inability to 

restore equipment prior to exceeding the LCO action time. As a practical matter, in order to 

meet the time limits for reportinq under § 50.72, the reporting decision should sometimes be 

based on such expectations. (See Example 4.) 

The "initiation of any nuclear plant shutdown" does not include mode changes required by TS 

if initiated after the plant is already in a shutdown condition. 

A reduction in power for some other purpose, not constituting initiation of a shutdown required 

by TS, is not reportable under this criterion. 

For § 50.73 reporting purposes, the phrase "completion of any nuclear plant shutdown" is 

defined as the point in time during a TS required shutdown when the plant enters the first 

shutdown condition required by a limiting condition for operations (LCO) [e.g., hot standby 

(Mode 3) for PWRs] with the standard technical specifications (STS). For example, if at 0200 

hours a plant enters an LCO action statement that states, "restore the inoperable channel to 

operable status within 12 hours or be in at least Hot Standby within the next 6 hours," the plant 

must be shut down (i.e., at least in hot standby) by 2000 hours. An LER is required if the 

inoperable channel is not returned to operable status by 2000 hours and the plant enters hot 

standby. 

An LER is not required if a failure was or could have been corrected before a plant has 

completed shutdown (as discussed above) and no other criteria in § 50.73 apply. 

Examples 

(1) Initiation of a TS-Reauired Plant Shutdown 

While operating at 100-percent power, one of the battery chargers, which feeds a 125 Vdc 

vital bus, failed during a surveillance test. The battery charger was declared inoperable, 

placing the plant in a 2-hour LCO to return the battery charger to an operable status or 

commence a TS-required plant shutdown. Licensee personnel started reducing reactor 

power to achieve a nuclear plant shutdown required by a TS when they were unable to 

complete repairs to the inoperable battery charger in the 2 hours allowed. The cause of 

the battery charger failure was subsequently identified and repaired. Upon completion of 

surveillance testing, the battery charger was returned to service and the TS required plant 

shutdown was stopped at 96-percent power. 

The licensee made an ENS notification because of the initiation of a TS-required plant

NUREG-1 022, Rev. 2 30
shutdown. An LER was not required under this criterion since the failed battery charger 

was corrected before the plant completed shutdown. 

(2) Initiation and Completion of a TS-Required Plant Shutdown 

During startup of a PWR plant with reactor power in the intermediate range, two of the four 

reactor coolant pumps (RCPs) tripped when the station power transformer supplying power 

de-energized. With less than four RCPs operating, the plant entered a 1-hour LCO to be in 

hot standby. Control rods were manually inserted to place the plant in a shutdown 

condition. 

The licensee made an ENS notification because of the initiation of a TS-required plant 

shutdown. An LER was required because of the completion of the TS-required plant 

shutdown. 

(3) Failure that was or could have been corrected before a plant has conpleted shut down 

was required. 

"Question: What about the situation where you have seven days to fix a component or 

be shut down, but the plant must be shut down to fix the component? Assume the 

plant shuts down, the component is fixed, and the plant returns to power prior to the 

end of the seven day period. Is that situation reportable? 

Answer: No. If the shutdown was not required by the Technical Specifications, it need 

not be reported. However, other criteria in 50.73 may apply and may require that the 

event be reported. 

" Question: Suppose that there are seven days to fix a problem and it is likely the 

problem can be fixed during this time period. However, the plant management elects to 

shut down and fix this problem and other problems. Is an LER required? 

Answer: No. omne judgm e.ntis required. An LEF. is not req.ired Of the situation could 

have been .. rre.ted beff.re the plant was required to be shut down, and me other 

,rtera• in 50.73 apply. The shut down is reportable, however, if the situation could not 

have been corrected before the plant was required to be shut down, or if other criteria 

of 5.73 a.pply. 

(4). Initiation of plant shutdown in anticipation of LCO required shutdown. 

The plant lost one of two sources of offsite power due to overheating in the main 

transformer. The TS allow 72 hours to restore the source or initiate a shutdown and be in 

HOT STANDBY in the next 6 hours and COLD SHUTDOWN in the following 30 hours. The 

licensee estimated that the transformer problem could not be corrected within the LCO 

action time. Therefore the decision was made to start a shutdown soon after the 

transformer oroblem was discovered.

NUREG-1022, Rev. 2

The shutdown was uneventful and was completed, with the plant in HOT STANDBY, prior 

to the expiration of the LCO action time. After the plant reached HOT STANDBY, further

31
e.valuation indicated that the transformer oroblem could not be corrected prior to the

requirement to place the plant in COLD SHUTDOWN. Based on this time estimate, it was 

decided to place the unit in COLD SHUTDOWN. 

The event is reportable under § 50.72(b)(2)(i) as the initiation of plant shutdown required by 

TS because, at the time the shutdown was initiated, and the time the report was due, it was 

not expected that the equipment would be restored to operable status within the required 

time. This is based on the fact that the reporting requirement is intended to capture those 

events for which TS require the initiation of a reactor shutdown. 

The event is reportable under § 50.73(a)(2)(i)(A) because the plant shutdown was 

completed when the plant reached HOT STANDBY (Mode 3). Had the transformer been 

repaired and the shutdown process terminated before the plant reached Mode 3, the event 

would not be reportable under § 50.73(a)(2)(i)(A). 

3.2.2 Operation or Condition Prohibited by Technical Specifications 

§ 50.72 § 50.73(a)(2)(i)(B) 

There is no corresponding "Any operation or condition which was prohibited by 

requirement in § 50.72. the plant's Technical Specifications except when: 

(1) The Technical Specification is administrative in 

nature', 

(2) The event consisted solely of a case of a late 

surveillance test where the oversight was corrected, the 

test was performed, and the equipment was found to be 

capable of performing its specified safety functions; or 

(3) The Technical Specification was revised prior to 

discovery of the event such that the operation or 

condition was no longer prohibited at the time of 

discovery of the event." 

An LER is required for any operation or condition which was prohibited by the plant's technical 

specifications, subiect to the exceptions stated in the rule. The NRC expects licensees to 

include violations of the Technical Specifications in their corrective action programs, which are 

subiect to NRC audit. 

Discussion

3 

Safety Limits and Limiting Safety System Settings 

Section 50.36(c)(1) outlines the reporting requirements in technical specifications for events 

3 This criterion does not address violations of license conditions that are contained in documents other 

than the technical specifications. Such violations are reportable as specified in the plant's license or other 

applicable documents.

NUREG-1022, Rev. 2 32
where safety limits or limiting safety system settings are exceeded. It indicates that such 

reports are to be made as required by §§ 50.72 and 50.73. There would not be a three year 

limitation in this case because, in addition to the requirements of §§ 50.72 and 50.73, specific 

reporting requirements are stated in § 50.36(c)(1), and perhaps in the plant's technical 

specifications. 

Limiting Conditions for Operation (LCOs) 

Section 50.36(c)(2) outlines LCOs in technical specifications. Certain technical specifications 

contain LCO statements that include action statements [required actions and associated 

completion time in the Improved Standard Technical Specifications (ISTS)] to provide 

constraints on the length of time components or systems may remain inoperable or out of 

service before the plant must shut down or other compensatory measures must be taken. 

Such time constraints are based on the safety significance of the component or system being 

removed from service. 

An LER is required if a condition existed for a time longer than permitted by the technical 

specifications [i.e., greater than the allowed outage time (or completion time in ISTS)] even if 

the condition was not discovered until after the allowable time had elapsed and the condition 

was rectified immediately upon discovery. This guidance is consistent with that previously 

given. (For the purpose of this discussion, it is assumed that there was firm evidence that a 

condition prohibited by technical specifications existed before discovery, for a time longer than 

permitted by technical specifications.) 

Technical Specification Surveillance Testing 

Section 50.36(c)(3) outlines surveillance requirements in technical specifications which assure 

(1) necessary quality of systems and components, (2) operation within safety limits, and 

(3) meeting the limiting conditions for operation. 

Generally, an operation or condition prohibited by the technical specifications existed and is 

reportable if surveillance testing indicates that equipment (e.g., one train of a multiple train 

system) was not capable of performing its specified safety functions (and thus was inoperable) 

for a period of time longer than allowed by technical specifications (i.e., LCO allowed outage 

time, or completion time for restoration of equipment in ISTS). Reporting is not required if an 

event consists solely of a case of a late surveillance test where the oversight is corrected, the 

test is performed, and the equipment is found to be capable of performing its specified safety 

functions. 

For the purpose of evaluating the reportability of a discrepancy found during surveillance 

testing that is required by the technical specifications: 

(1) For testing that is conducted within the required time (i.e., the surveillance interval plus any 

allowed extension), it should be assumed that the discrepancy occurred at the time of its 

discovery unless there is firm evidence, based on a review of relevant information such as 

the equipment history and the cause of failure, to indicate that the discrepancy existed 

previously.

33 NUREG-1022, Rev. 2
(2) For testing that is conducted later than the required time, it should be assumed that the 

discrepancy occurred at the time the testing was required unless there is firm evidence to 

indicate that it occurred at a different time. 

The purpose of this approach is two-fold. It rules out reporting of routine occurrences (i.e., 

occurrences where a timely surveillance test is performed, the results fall outside of acceptable 

limits, and the condition is corrected) unless there is firm evidence that equipment was 

incapable of performing its specified safety function longer than allowed. On the other hand, if 

the surveillance test is performed substantially late, and the equipment is not capable of 

performing its specified safety function, the occurrence is not routine. In this case the event is 

reportable unless there is firm evidence that the duration of the discrepancy was within allowed 

limits. 

In cases where it is discovered that a surveillance test was not performed within its specified 

frequency or interval, some plants have technical specifications which allow a delay of up to 24 

hours in declaring an LCO or technical specifications requirements not met. This allows time 

to perform the test before making such a declaration and taking other required actions. 

However, an LER would still be required if the test indicates that equipment (e.g., one train of a 

multiple train system) was not capable of performing its specified safety functions (and thus 

was inoperable) for a period of time longer than allowed by technical specifications. The 

allowed delay in declaring the LCO not met does not change the fact that the condition existed 

longer than allowed by technical specifications. 

Tests Required by ASME Section XI 

Sections 50.55a(g) and 50.55a(f) require the implementation of ISI and IST programs in 

accordance with the applicable edition of the ASME Code for those pumps and valves whose 

function is required for safety. Standard technical specifications (STS) Section 4.0.5 (or an 

equivalent) covers these testing requirements. 

As with surveillance testing, an operation or condition prohibited by the technical specifications 

existed and is reportable if the testing indicates that equipment (e.g., one train of a multiple 

train system required to be operable by the technical specifications) was not capable of 

performing its specified safety functions (and thus was inoperable) for a period of time longer 

than allowed by technical specifications (i.e., LCO allowed outage time, or completion time for 

restoration of equipment in ISTS). Accordingly, similar assumptions and standards should be 

used. For example, if a timely test indicates that equipment is not capable of performing its 

specified safety function, it should be assumed that the discrepancy occurred at the time of the 

test unless there is firm evidence to indicate that it existed previously. 

Design and Analysis Defects and Deviations 

A design or analysis defect or deviation is reportable under this criterion if, as a result, 

equipment (e.g., one train of a multiple train system) was not capable of performing its 

specified safety functions (and thus was inoperable) for a period of time longer than allowed by 

technical specifications. Since design and analysis conditions are long-lasting, the essential 

question in this case is whether the equipment was capable of performing its specified safety 

functions.

NUREG-1022, Rev. 2 34
Administrative Requirements

Section 6 of the STS (Section 5 of ISTS), or its equivalent, has a number of administrative 

requirements such as organizational structure, the required number of personnel on shift, the 

maximum hours of work permitted during a specific interval of time, and the requirement to 

have, maintain, and implement certain specified procedures. Violation of a technical 

specification that is administrative in nature is not reportable. 

For example, a change in the plant's organizational structure that has not yet been approved 

as a technical specification change would not be reportable. 

An administrative procedure violation, or failure to implement a procedure, such as failure to 

lock a high radiation area door, is generally not reportable under this criterion. Radiological 

conditions and events that are reportable are defined in 10 CFR 20.2202 and 20.2203. 

Redundant reporting is not required. 

Entry into STS 3.0.3 

STS 3.0.3 (ISTS LCO 3.0.3), or its equivalent, establishes requirements for actions when: 

(1) an LCO is not met and the associated ACTIONS are not met; (2) an associated ACTION is 

not provided, or (3) as directed by the associated ACTIONS themselves. 

Entry into STS 3.0.3 (ISTS LCO 3.0.3) or its equivalent is geerally reportable under this 

eriterion-is not necessarily reportable under this criterion. However, it should be considered 

reportable under this criterion if the condition is not corrected within an hour, such that it is 

necessary to initiate actions to shutdown, cool down, etc. 

Revised Technical Specifications 

An LER is not required for discovery of an operation or condition that occurred in the past and 

was prohibited at the time it occurred if, prior to the time of discovery, the technical 

specifications were revised such that the operation or condition is no longer prohibited. Such 

an event would have little or no significance because the operation or condition would have 

been determined to be acceptable and allowed under the current technical specifications. 

Examples 

(1) LCO Exceeded 

In conducting a timely 30-day surveillance test a licensee found a standby component with 

a 7-day LCO allowed outage time and associated 8-hour shutdown action statement to be 

inoperable. (This is equivalent to a 7-day restoration completion time and an 8-hour action 

completion time in ISTS.) Subsequent review indicated that the component was 

assembled improperly during maintenance conducted 30 days previously and the post

maintenance test was not adequate to identify the error. Thus, there was firm evidence 

that the standby component had been inoperable for the entire 30 days. 

An LER was required because the condition existed longer than allowed by the technical

35 NUREG-1022, Rev. 2
specifications (7-day LCO allowed outage time and the shutdown action statement time of 

8 hours). Had the inoperability been identified and corrected within the required time, the 

event would not be reportable. 

(2) Late Surveillance Tests 

A licensee, with the plant in Mode 5 following a 10-month refueling outage, determined that 

certain monthly technical specifications surveillance tests, which were required to be 

performed regardless of plant mode, had not been performed as required during the 

outage. The STS 4.0.2 (equivalent to ISTS SR 3.0.2) extension was also exceeded. The 

surveillance tests were immediately performed. 

No LER would be required if the test showed the equipment was still capable of performing 

its specified safety functions. On the other hand, if the test showed the equipment was not 

capable of performing its specified safety functions (and thus was inoperable) in excess of 

the allowed time, the event would be reportable. 

(a) With essential water chillers (A) and (B) out of service, the only remann orable ehille~r 

(NB) tripped. This condition caused the plant to enter STS 3.0.3 (equivalent to l6'TSLO 

"3.0.3) for 1 houir, .hiller u-ntil (A) was restored to se. . .e and the temperature was restored 

to wi.thin tehni ,al specifi:ations- limits. 

(b) During a surveillan.e test on the A train of a twvo train Standby Gas Treatment (SB'T) 

system. , condition was discovered on the B trai- that rendered it inoPerable. The test 

was halted and steps taken to return the A train to a stadb read1 es condition. During 

the restoration, switch mnanipulations momentarily rendered the A tr-ain inoperable. With 

both trains i able, the plant TO specify immediate entry into LOG 3.0.3. The entry into 

LCO 3.0.3 was log ed and then exited within 1 ,minute o.nc. e switch manip,, lation on the A 

train was comnpleted-. 

(3) Multiple Test Failures 

An example of multiple test failures involves the sequential testing of safety valves. 

Sometimes multiple valves are found to lift with set points outside of technical specification 

limits. 

As discussed above, discrepancies found in technical specifications surveillance tests 

should be assumed to occur at the time of the test unless there is firm evidence, based on 

a review of relevant information (e.g., the equipment history and the cause of failure) to 

indicate that the discrepancy occurred earlier. However, the existence of similar 

discrepancies in multiple valves is an indication that the discrepancies may well have 

arisen over a period of time and the failure mode should be evaluated to make this 

determination. If so, the condition existed during plant operation and the event is 

reportable under § 50.73(a)(2)(i)(B) "Any operation or condition prohibited by the plant's 

Technical Specifications."

NUREG-1022, Rev. 2 36
If the discrepancies are large enough that multiple valves are inoperable the event may 

also be reportable under § 50.73(a)(2)(vii) "Any event where a single cause or condition 

caused at least one independent train or channel to become inoperable in multiple systems 

or two independent trains or channels to become inoperable in a single system ...... 

(4) Seismic Restraints 

Assume it is found that an exciter panel for one EDG lacked appropriate seismic restraints 

since the plant was constructed, because of a design, analysis, or construction 

inadequacy. Upon evaluation, the EDG is determined to be inoperable because it is not 

capable of performing its specified safety functions during and after an SSE. 

An LER would be required because the plat was outside of its design basis the EDG was 

inoperable for a period of time longer than allowed by TS. 

L6 Vulnerability to Loss of Offsite Power 

Assume that during a design review it is found that a loss of offsite power could cause a 

loss of instrument air and, as a result, auxiliary feedwater (AFW) flow control valves could 

fail open. Then for low steam generator pressure, such as could occur for certain main 

steam line breaks, high AFW flow rates could result in tripping the motor driven AFW 

pumps on thermal overload. Therefore, the motor-driven AFW pumps are determined to 

be inoperable. The single turbine driven AFW pump is not affected. 

An LER would be required because the motor-driven portion of AFW was inoperable for a 

period of time longer than allowed by the technical specifications. 

3.2.3 Deviation from Technical Specifications under § 50.54(x) 

§ 50.72(b)(1) § 50.73(a)(2)(i)(C) 

"... any deviation from the plant's "Any deviation from the plant's 

Technical Specifications authorized Technical Specifications authorized 

pursuant to § 50.54(x) of this part." pursuant to § 50.54(x) of this part." 

An LER is required for a deviation authorized pursuant to Section 50.54(x). If not reported 

under § 50.72(a), an ENS notification is also required. 

Discussion 

10 CFR 50.54(x) generally permits licensees to take reasonable action in an emergency even 

though the action departs from the license conditions or plant technical specifications if (1) the 

action is immediately needed to protect the public health and safety, including plant personnel, 

and (2) no action consistent with the license conditions and technical specifications is

37 NUREG-1022, Rev. 2
immediately apparent that can provide adequate or equivalent protection. Deviations 

authorized pursuant to 10 CFR 50.54(x) are reportable under this criterion. 

Example 

With the plant at 100-percent power, the upper containment airlock inner door was opened to 

allow a technician to exit from the containment while the upper airlock outer door was 

inoperable, resulting in the loss of containment integrity. The upper airlock door was 

inoperable pending retests following seal replacement. The technician was inside containment 

when the lower airlock failed, requiring the technician to exit through the upper door. 

The licensee decided to exercise the option allowed for under 10 CFR 50.54(x) and open the 

upper containment airlock inner door. In this instance, immediate action was considered 

necessary to protect the safety of the technician. The upper airlock was not scheduled to be 

returned to operability for another 20 hours and the time to repair the lower airlock door was 

unknown. 

When the action was completed the control room operators notified the NRC Operations 

Center, in accordance with the reporting requirements of 10 CFR 50.72, that they had 

exercised 10 CFR 50.54(x). Subsequently, an LER was required in accordance with 10 CFR 

50.73(a)(2)(i) {use of 10 CFR 50.54(x)} as well as 10 CFR 50.73(a)(2)(v) {event or condition 

that could have prevented .... ). 

3.2.4 Degraded or Unanalyzed Condition

§ 50.72(b)(3)(ii) 

"Any event or condition that results in: 

(A) The condition of the nuclear power 

plant, including its principal safety barriers, 

being seriously degraded; or 

(B) The nuclear power plant being in an 

unanalyzed condition that significantly 

degrades plant safety." 

in a eond~tion that 4s outsqde the design 

basis of the plant; or 

in a eonditin not eevered by the plant's 

oneratinn and efflamenev nreceedurer.-"

§ 50.73(a)(2)(ii) 

"(a)(2)(ii) Any event or condition that 

resulted in: 

(A) The condition of the nuclear power 

plant, including its principal safety barriers, 

being seriously degraded; 

(B) The nuclear power plant being 

in an unanalyzed condition that significantly 

degraded plant safety."

design basis of the plant; or,

operating. and e. .erc.enc.r..... res. -I ~~I.., -

An LER is required for a seriously degraded principal safety barrier or an unanalyzed condition 

that significantly degrades plant safety. If not reported under § 50.72(a), (b)(1), or (b)(2) an 

ENS notification is required under § 50.72(b)(3) [an 8-hour report].

NUREG-1022, Rev. 2

in - eeindifie- that was As itQmAm the

li .. . ....... -- ... ... . I-Rnd4 I~ h~ tIa I * m*'Q

38
Discussion

(A) Nuclear power plant, including its principal safety barriers, being seriously degraded: 

This criterion applies to material (e.g., metallurgical or chemical) problems that cause abnormal 

degradation of or stress upon the principal safety barriers (i.e., the fuel cladding, reactor 

coolant system pressure boundary, or the containment). Abnormal degradation of a barrier 

may be indicated by the necessity of taking corrective action to restore the barrier's capability, 

as is the case in some of the examples discussed below. Abnormal stress upon a barrier may 

result from an unplanned transient, as is the case in one of the examples discussed below. 

Examples of reportable events and conditions are: 

(1) Fuel cladding failures in the reactor, or in the storage pool, that exceed expected 

values, or that are unique or widespread, or that are caused by unexpected factors. 

(2) Welding or material defects in the primary coolant system which cannot be found 

acceptable under ASME Section Xl, IWB-3600, "Analytical Evaluation of Flaws" or 

ASME Section Xl, Table IWB-341 0-1, "Acceptance Standards." 

( Serious steam generator tube degradation. Steam generator tube degradation is 

considered serious if the tubing fails to meet the following two performance criteria: 

Lal Steam generator tubing shall retain structural integrity over the full range of normal 

operating conditions (including startup, operation in the power range, hot standby, 

and cooldown and all anticipated transients included in the design specification) 

and design basis accidents. This includes retaininq a margin of 3.0 against burst 

under normal steady state full power operation and a margin of 1.4 against burst 

under the limiting design basis accident concurrent with a safe shutdown 

earthquake. 

(13) The primary to secondary accident induced leakage rate for the limiting design 

basis accident, other than a steam generator tube rupture, shall not exceed the 

leakage rate assumed in the accident analysis in terms of total leakage rate for all 

steam generators and leakage rate for an individual steam generator. The licensing 

basis accident analyses typically assume a 1 g.p.m. primary to secondary leak rate 

per steam generator, except for specific types of degradation at specific locations 

where the tubes are confined, as approved by the NRC and enumerated in 

conjunction with the list of approved repair criteria in the licensee's design basis 

documents. 

(4) Low temperature over pressure transients where the pressure-temperature relationship 

violates pressure-temperature limits derived from Appendix G to 10 CFR Part 50 (e.g., 

TS pressure-temperature curves). 

(5) Loss of containment function or integrity, including containment leak rate tests where

39 NUREG-1022, Rev. 2
the total containment as-found, minimum-pathway leak rate exceeds the limiting 

condition for operation (LCO) in the facility's TS.4 

(B) Unanalyzed condition that significantly affects plant safety: 

As was indicated in the 1983 Statements of Considerations for 10 CFR 50.72 and 50.73, with 

regard to an Unanalyzed condition that significantly compromises plant safety, 

The Commission recognizes that the licensee may use engineering judgment and 

experience to determine whether an unanalyzed condition existed. It is not intended 

that this paragraph apply to minor variations in individual parameters, or to problems 

concerning single pieces of equipment. For example, at any time, one or more safety

related components may be out of service due to testing, maintenance, or a fault that 

has not yet been repaired. Any trivial single failure or minor error in performing 

surveillance tests could produce a situation in which two or more often unrelated, 

safety-grade components are out-of-service. Technically, this is an unanalyzed 

condition. However, these events should be reported only if they involve functionally 

related components or if they significantly compromise plant safety.5 

When applying engineering judgment, and there is a doubt regarding whether to report or not, 

the Commission's policy is that licensees should make the report.6 

For example, small voids in systems designed to remove heat from the reactor core which 

have been previously shown through analysis not to be safety significant need not be reported. 

However, the accumulation of voids that could inhibit the ability to adequately remove heat 

from the reactor core, particularly under natural circulation conditions, would constitute an 

unanalyzed condition and would be reportable. 

In addition, voiding in instrument lines that results in an erroneous indication causing the 

operator to misunderstand the true condition of the plant is also an unanalyzed condition and 

should be reported. 8 

The level of significance of these cases generally corresponds to the inability to perform a 

required safety function. For instance, accumulation of voids that could inhibit the ability to 

adequately remove heat from the reactor core, particularly under natural circulation conditions, 

4 The LCO typically employs La, which is defined in Appendix J to 10 CFR Part 50 as the maximum 

allowable containment leak rate at pressure Pa, the calculated peak containment internal pressure related to the 

design basis accident. Minimum-pathway leak rate means the minimum leak rate that can be attributed to a 

penetration leakage path; for example, the smaller of either the inboard or outboard valve's individual leak rates. 

5 48 FR 39042, August 29, 1983 and 48 FR 33856, July 26, 1983. 

6 48 FR 39042, August 29,1983. 

7 48 FR 39042, August 29, 1983 and 48 FR 33856, July 26, 1983. 

8 48 FR 39042, August 29, 1983 and 48 FR 33856, July 26, 1983.

NUREG-1022, Rev. 2 40
has an effect similar to a condition that could prevent the fulfillment of the safety function of 

the auxiliary feedwater system. 

Beyond the examples given in 1983, an example of an event reportable as a cndition Outside 

the ei basis of the plant an unanalyzed condition that significantly degraded plant safety 

would be the discovery that a system required to meet the single failure criterion does not do 

so. 

In another example, if fire barriers are found to be missing, such that the required degree of 

separation for redundant safe shutdown trains is lacking, the event would be reportable as a 

ndto-. -- outside . the design basis of the plant an unanalyzed condition that significantly 

degraded plant safety. On the other hand, if a fire wrap, to which the licensee has committed, 

is missing from a safe shutdown train but another safe shutdown train is available in a different 

fire area, protected such that the required separation for safe shutdown trains is still provided, 

the event would not be reportable. 

Examples 

(1) SZinificant Decgradation Failures of Reactor Fuel Rod Cladding Identified During Testing of 

Fuel Assemblies 

Radio-chemistry data for a particular PWR indicated that a number of fuel rods had failed 

during the first few months of operation. Projections ranged from 6 to 12 failed rods. The 

end of cycle reactor coolant system iodine-1 31 activity averaged 0.025 micro curies per 

milliliter. Following the end of cycle shutdown, iodine-131 spiked to 11.45 micro curies per 

milliliter. The cause was due to a significant number of failed fuel rods. Inspections 

revealed that 136 of the total 157 fuel assemblies contained failed fuel (approximately 300 

fuel rods had through-wall penetrations), far exceeding the anticipated number of failures. 

The defects were generally pinhole sized. The fuel cladding failures were caused by long

term fretting from debris that became lodged between the lower fuel assembly nozzle and 

the first spacer grid, resulting in penetration of the stainless-steel fuel cladding. The source 

of the debris was apparently a machining byproduct from the thermal shield support system 

repairs during the previous refueling outage. 

An ENS notification is required becus a prncipal safety barrier (the fuel cladding) was 

fo•,nd seriously degraded. An LEr- is required,. The event is reportable because the 

cladding failures exceed expected values, and are unigue or widespread. 

(2) Reactor Coolant System Pressure Boundary Degradation due to Corrosion of a Control 

Rod Drive Mechanism Flange 

While the plant was in hot shutdown, a total of six control rod drive mechanism (CRDM) 

reactor vessel nozzle flanges were identified as leaking. Subsequently one of the flanges 

was found eroded and pitted. While removing the nut ring from beneath the flange, it was 

discovered that approximately 50 percent of one of the nut ring halves had corroded away 

and that two of the four bolt holes in the corroded nut ring half were degraded to the point 

where there was no bolt/thread engagement.

41 NUREG-1022, Rev. 2
An inspection of the flanges and spiral wound gaskets, which were removed from between 

the flanges, revealed that the cause of the leaks was the gradual deterioration of the 

gaskets from age. A replacement CRDM was installed and the gaskets on all six CRDMs 

were replaced with new design graphite-type gaskets. 

An ENS notif.latien is required because the clndition caused a significant degradatiom of 

the pressure boundary. ,S An LER s require. The event is reportable because there is 

a material defect in the primary coolant system which cannot be found acceptable under 

ASME Section Xl. 

(3) Siei,•if•cant-Degradation of Reactor Fuel Rod Cladding Identified During Fuel Sipping 

Operations 

With the plant in cold shutdown, fuel sipping operations appeared to indicate a significant 

portion of cycle 2 fuel, type "LYP," had failed, i.e., four confirmed and twelve potential fuel 

leakers. The potential fuel leakers had only been sipped once prior to making the ENS 

notification. The licensee contacted the fuel vendor for assistance on-site in evaluating this 

problem. 

An ENS notification was made because the fuel cladding degradation was thought to be 

widespread. However, additional sipping operations and a subsequent evaluation by the 

licensee's reactor engineering department with vendor assistance concluded that no 

additional fuel failures had occurred, i.e., the abnormal readings associated with the 

potential fuel leakers was attributed to fission products trapped in the crud layer. Based on 

the results of the evaluation the licensee concluded that the fuel cladding was not seriously 

degraded and that the event was not reportable. Consequently, after discussion with the 

Regional Office, the licensee appropriately retracted this event. 

3.2.5 External Threat or Hampering 

§ 50.72 § 50.73(a)(2)(iii) 

The corresponding requirement in "Any natural phenomenon or other 

§ 50.72 has been deleted. external condition that posed an actual 

Refer to the plant's Emergency Plan threat to the safety of the nuclear power 

regarding declaration of an Emergency plant or significantly hampered site 

Class. personnel in the performance of duties 

necessary for the safe operation of the 

nuclear power plant." 

An LER is required for any natural phenomenon or other external condition that poses an 

actual threat to the safety of the nuclear power plant or significantly hampers site personnel in 

the performance of duties necessary for the safe operation of the plant.

NUREG-1022, Rev. 2 42
Discussion

This criterion applies only to acts of nature (e.g., tornadoes, earthquakes, fires, lightning, 

hurricanes, floods) and external hazards (i.e., industrial or transportation accidents). 

References to acts of sabotage are covered by 10 CFR 73.71. Actual threats or significant 

hampering from internal hazards are covered by a separate criterion in § 50.73(a)(2)(ix), as 

discussed in Section 3.2.10 of this report. 

The phrase "actual threat to safety of the nuclear power plant" is one reporting trigger. This 

covers those events involving an actual threat to the plant from an external condition or natural 

phenomenon where the threat or damage challenges the ability of the plant to continue to 

operate in a safe manner (including the orderly shutdown and maintenance of shutdown 

conditions). 

The licensee should decide if a phenomenon or condition actually threatens the plant. For 

example, a minor brush fire in a remote area of the site that is quickly controlled by fire fighting 

personnel and, as a result, did not present a threat to the plant should not be reported. 

However, a major forest fire, large-scale flood, or major earthquake that presents a clear threat 

to the plant should be reported. As another example, an industrial or transportation accident 

which occurs near the site, creating a plant safety concern, should be reported. 

The licensee must use engineering judgment to determine if there was an actual threat. For 

example, with regard to tornadoes the decision would be based on such factors as the size of 

the tornado, and its location and path. There are no prescribed limits. In general, situations 

involving only monitoring by the plant's staff are not reportable, but if preventive actions are 

taken or if there are serious concerns, then the situation should be carefully reviewed for 

reportability. 

Responsive actions, by themselves, do not necessarily indicate actual threats. Those which 

are purely precautionary, such as placement of sandbags, even though flood levels are not 

expected to be high enough to require sandbags, do not trigger reporting. 

Somne natural phenomnena stich as floods may be aeiately d predieted. if there is a eredible 

predietion of a flood that would challenge the ability of the plant to eontinuie to operate safely, 

the threat is reportable as an aetuial threat via ENS as soon as practieal and in all eases Within 

four hours. 

Section 3.2.10 of this report discusses the meaning of the phrase "significantly hampers site 

personnel in the performance of duties necessary for the safe operation of the plant," in the 

context of internal threats. A natural phenomenon or external condition may also significantly 

hamper personnel. If so, it is reportable under this criterion. 

If a snowstorm, hurricane or similar event significantly hampers personnel in the conduct of 

activities necessary for the safe operation of the plant, the event is reportable. In the case of 

snow, the licensee must use judgment based on the amount of snow, the extent to which 

personnel were hampered, the extent to which additional assistance could have been available 

in an emergency, the length of time the condition existed, etc. For example, if snow prevented 

shift relief for several hours, the situation would be reportable if the delay were such that site

43 NUREG-1022, Rev. 2
personnel were significantly hampered in the performance of duties necessary for safe 

operation. For example, shift personnel might exceed normal shift overtime limits, become 

excessively fatigued, or find it necessary to operate with fewer than the required number of 

watch-standers in order to allow some to rest. 

Examples 

(1) Earthquake 

Seismic alarms were received in the Unit 1 control room of a Southern California plant. 

Seismic monitors were not tripped in Units 2 or 3. The earthquake was readily felt on site. 

Seismic instrumentation measured less than 0.02 g lateral acceleration. 

The licensee classified this as an Unusual Event in accordance with the emergency plan 

and notified the NRC via ENS per § 50.72(a)(1)(i) within 30 minutes of the earthquake. 

The licensee terminated the event after walk-downs of the plant were satisfactorily 

completed and made an ENS update call. No LER was submitted because the event was 

not considered to be an actual threat. 

(2) Hurricane 

A licensee in southern Florida declared an Unusual Event after a hurricane warning was 

issued by the National Hurricane Center. The hurricane was predicted to reach the site in 

approximately 24 hours. As part of the licensee's severe weather preparations both 

operating units were taken to hot shutdown before the hurricane's predicted arrival. Offsite 

power to both units was lost. As the hurricane approached, wind velocity on site was 

measured in excess of 140 mph. All personnel were withdrawn to protected safety-related 

structures. Extensive damage occurred on site. The Unusual Event was upgraded to an 

Alert when the pressurized fire header was lost because of storm-related damage to the 

fire protection system water supply piping and electric pump. All safety-related equipment 

functioned as designed before, during, and after the storm with the exception of two minor 

emergency diesel generator anomalies. The licensee downgraded the Alert to an Unusual 

Event once offsite power was restored and a damage assessment completed. 

An ENS notification was required because the licensee declared an emergency class. An 

LER was required, based on the occurrence of a natural phenomenon that posed an actual 

threat and several other reporting criteria as well. 

(3) Fire 

With the unit at 100-percent power, the control room was notified that a forest fire was 

burning west of the plant close to the 230-kV distribution lines., Approximately 15 minutes 

later, voltage fluctuations were observed and then a full reactor scram occurred. The 

licensee determined that the offsite distribution breakers had tripped on fault, apparently 

from heavy smoke and heat in the vicinity of the offsite 230-kV line insulators. The other 

source of offsite power, i.e., the 34.5-kV lines supplying the startup transformers, was also 

lost. Both station emergency diesel generators received a fast start signal and load 

sequenced as designed. Five minutes later, offsite power was available through the

NUREG-1022, Rev. 2 44
startup transformer to the non-safety-related 4160-v buses, but the licensee decided to 

maintain the vital buses on their emergency power source until the reliability of offsite 

power could be assured. The fire continued to burn and, although no plant structures or 

equipment were directly affected, the fire did approach within 70 feet of the fire pump 

house. 

An ENS notification was required because the licensee entered the emergency plan, 

declaring an Unusual Event based on high drywell temperature and an Alert based on the 

potential of the forest fire to further affect the plant. An LER was required, based on the 

occurrence of natural phenomenon that posed an actual threat and several other reporting 

criteria as well. 

3.2.6 System Actuation

§ 50.72(b)(2)(iv) 

"(A) Any event that results or should 

have resulted in emergency core cooling 

system (ECCS) discharge into the reactor 

coolant system as a result of a valid signal 

except when the actuation results from and 

is part of a pre-planned sequence during 

testina or reactor oDeration.

(B) Any event or condition that results in 

actuation of the reactor protection system 

(RPS) when the reactor is critical except 

when the actuation results from and is part 

of a pre-planned sequence during testing or 

reactor operation."

§ 50.72(b)(3)(iv) 

"(A) Any event or condition that results 

in valid actuation of any of the systems 

listed in paragraph (b)(3)(iv)(B) of this 

section except when the actuation results 

from and is part of a pre-planned sequence 

during testing or reactor operation.

(B) Te I actuation is invaI•d and: 

(1) Occu rs while the systemn is properly 

removed from service; 

(•. OciUrs after the safety ftuiItion has 

been already orImpleted;- or 

(8)/ Involves only the following speeif.C

§ 50.73(a)(2)(iv) 

"(A) Any event or condition that resulted 

in manual or automatic actuation of any of 

the systems listed in 0arawraph (a)(2)(iv)(B)

of this section, 

except when: 

(1) The actuation resulted from and was 

part of a pre-planned sequence during 

testing or reactor operation; or 

(2) The actuation was invalid and; 

(i) Occurred while the system was 

properly removed from service; or 

(ii) Occurred after the safety function 

had been already completed.

tuvolveaG __ Oily Me TCuOW In specific

NUREG-1022, Rev. 2

I

1- 1. . . . .. I ,; .

45
- I0 UI V 1 U VCIL I . OYQ l Ito.

M / a te " terI..U C~3|; !• .II- IJ O ý. I.,l 

A.i) C ,ntrl roum e,,ergeney ventilation 

systern; 

Rh; feaetor building ventilation systern, 

(iv) Fuel building ventiation systern; er 

(v) Auxiliary btfilding ventilation systemn. 

(B) The systems to which the 

requirements of paragraph (b)(3)(iv)(A) of

this section apply are: 

(1) Reactor protection system (RPS) 

includina: reactor scram and reactor trip.'

(2) General containment isolation

signals affecting containment isolation 

valves in more than one system or multiple

main steam isolation valves (MSIVs).

(3) Emergency core cooling systems 

(ECCS) for pressurized water reactors 

(PWRs) including: high-head, intermediate

head, and low-head iniection systems and 

the low pressure iniection function of

residual (decay) heat removal systems.

('4) ECOS for boiling water reactors

(BWRs) including: high-pressure and low

pressure core spray systems: high-pressure

coolant iniection system: low pressure

iniection function of the residual heat

removal system. 

(5) BWR reactor core isolation cooling 

system: isolation condenser system: and

feedwater coolant iniection system. 

(6) PWR auxiliary or emeraencv

feedwater system. 

(7) Containment heat removal and 

depressurization systems, including 

containment spray and fan cooler systems. 

(8) Emeraencv ac electrical power

systems, including: emergency diesel 

generators (EDGs): hydroelectric facilities 

used in lieu of EDGs at the Oconee Station:

and BWR dedicated Division 3 EDGs.

--Actuation of the RPS when the reactor is 

critical is reportable under paragraph

ECFs or their equivalent systems:

Vi7 Q .,-crr waxer ,• . I W,,

_ .... . "-

jill/ I1QIAJI LJUII'..III Ij vai IUIaLI'.JI I QLI II,

m] I LFt UIIuIIII VeInilatlII system, I 

(vq Auxiliary building ventilation. 

(B) The systems to which the 

requirements of paragraph (a)(2)(iv)(A) of 

this section apply are: 

(1) Reactor protection system (RPS) 

includinq: reactor scram or reactor trip. 

(2) General containment isolation 

sigqnals affectinq containment isolation

valves in more than one system or multiple 

main steam isolation valves (MSIVs). 

(3) Emeraencv core coolino systems

(EGOS) for Dressurized water reactors

(PWRs) including: high-head, intermediate

head, and low-head injection systems and

the low pressure iniection function of

residual (decay) heat removal systems. 

(4) ECCS for boiling water reactors

(BWRs) including: high-pressure and low

pressure core spray systems: hiah-pressure

coolant iniection system; low pressure 

iniection function of the residual heat 

removal system. 

(5) BWR reactor core isolation coolin[g 

system: isolation condenser system; and 

feedwater coolant iniection system.

(6) PWR auxiliary or emergency 

feedwater system. 

(7) Containment heat removal and 

depressurization systems, including 

containment spray and fan cooler systems. 

(8) Emergency ac electrical power 

systems, including: emergency diesel 

generators (EDGs): hydroelectric facilities 

used in lieu of EDGs at the Oconee Station;

and BWR dedicated Division 3 EDGs. 

(9) Emeraencv service water systems

that do not normally run and that serve as 

ultimate heat sinks.

(b.)1v of_ __this____section_ __

NUREG-1022, Rev. 2

r- L- F- 4 " b : i 4 4.

rsd ........ a hea remova svst----

(1l11 I u t kI(! inU U II I I•j VU"I %j"••|U I Y -y . I I

46
Discussion

An event involving a valid ECCS signal, or a critical scram, is reportable under § 50.72(b)(2)(iv) 

[a 4-hour report] unless the actuation resulted from and was part of a pre-planned sequence. 

A valid actuation of any of the systems named in § 50.72(b)(3)(iv)(B) is reportable under 

§ 50.72(b)(3)(iv)(A) [an 8-hour report] unless the actuation resulted from and was part of a pre

planned sequence during testing or reactor operation. 

An actuation of any of the systems named in § 50.73(a)(2)(iv)(B) is reportable under 

§ 50.73(a)(2)(iv)(A) [a 60-day report] unless the actuation resulted from and was part of a pre

planned sequence during testing or reactor operation or the actuation was invalid and 

occurred while the system was properly removed from service or occurred after the safety 

function had been already completed. As indicated in § 50.73(a)(1), in the case of an invalid 

actuation reported under § 50.73(a)(2)(iv)(A) other than actuation of the reactor protection 

system (RPS) when the reactor is critical the licensee may, at its option, provide a telephone 

notification to the NRC Operations Center within 60 days after discovery of the event instead 

of submitting a written LER. In these cases the telephone report: 

M Is not considered an LER. 

.21 Should identify that the report is being made under § 50.73(a)(2)(iv)(A). 

(3) Should provide the following information: 

(a The specific train(s) and system(s) that were actuated. 

{b Whether each train actuation was complete or partial. 

I Whether or not the system started and functioned successfully. 

These paragraphs require events to be reported whenever one of the specified systems 

actuates either manually or automatically, regaidless of lant status. it is They are based on 

the premise that these systems are provided to mitigate the consequences of a significant 

event and, therefore: (1) they should work properly when called upon, and (2) they should not 

be challenged frequently or unnecessarily. The Commission is interested both in events where 

a system was needed to mitigate the consequences of an event (whether or not the equipment 

performed properly) and events where a system actuated unnecessarily. 

Actuations that need not be reported are those initiated for reasons other than to mitigate the 

consequences of an event (e.g., at the discretion of the licensee as part of a preplanned 

procedure). 

The intent is to require reporting actuation of systems that mitigate the consequences of 

significant events. Usually, the staff would not consider this to include single component 

actuations because single components of complex systems, by themselves, usually do not 

mitigate the consequences of significant events. However, in some cases a component would

47 NUREG-1022, Rev. 2
be sufficient to mitigate the event (i.e., perform the safety unction) and its actuation would, 

therefore, be reportable. This position is consistent with the statement that the reporting 

requirement is based on the premise that these systems are provided to mitigate the 

consequences of a significant event. 

Single trains do mitigate the consequences of events, and, thus, train level actuations are 

reportable. 

In this regard, the staff considers actuation of a diesel-generator to be actuation of a train--not 

actuation of a single component -- because a diesel generator mitigates the event (performs 

the safety function for plan.ts at whi-h diesel generators are elassified as ESF systems). (See 

Example 3 below.) 

The staff also considers intentional manual actions, in which one or more system components 

are actuated in response to actual plant conditions resulting from equipment failure or human 

error, to be reportable because such actions would usually mitigate the consequences of a 

significant event. This position is consistent with the statement that the Commission is 

interested in events where a ssstem was needed to mitigate the consequences of the event. 

For example, starting a safety injection pump in response to a rapidly decreasing pressurizer 

level or starting HPCI in response to a loss of feedwater would be reportable. However, 

shifting alignment of makeup pumps or closing a containment isolation valve for normal 

operational purposes would not be reportable. 

Actuation of multichannel ESF-actuation systems is defined as actuation of enough channels 

to complete the minimum actuation logic. Therefore, single channel actuations, whether 

caused by failures or otherwise, are not reportable if they do not complete the minimum 

actuation logic. Note, however, that if only a single logic channel actuates when, in fact, the 

system should have actuated in response to plant parameters, this would be reportable under 

these paragraphs as well as under 10 CFR 50.72(b)(3)(v) and 10 CFR 50.73(a)(2)(v) (event or 

condition that could have prevented the fulfillment of the safety function of .... ). 

With regard to preplanned actuations, operation of a system as part of a planned test or 

operational evolution need not be reported. Preplanned actuations are those which are 

expected to actually occur due to preplanned activities covered by procedures. Such 

actuations are those for which a procedural step or other appropriate documentation indicates 

the specific actuation is actually expected to occur. Control room personnel are aware of the 

specific signal generation before its occurrence or indication in the control room. However, if 

during the test or evolution, the system actuates in a way that is not part of the planned 

evolution, that actuation should be reported. For example, if the normal reactor shutdown 

procedure requires that the control rods be inserted by a manual reactor scram, the reactor 

scram need not be reported. However, if unanticipated conditions develop during the 

shutdown that cause an automatic reactor scram, such a reactor scram should be reported. 

The fact that the safety analysis assumes that a system will actuate automatically during an 

event does not eliminate the need to report that actuation. Actuations that need not be 

reported are those initiated for reasons other than to mitigate the consequences of an event 

(e.g., at the discretion of the licensee as part of a planned evolution). 

Note that if an operator were to manually scram the reactor in anticipation of receiving an

NUREG-1022, Rev. 2 48
automatic reactor scram, this would be reportable just as the automatic scram would be 

reportable. 

Valid EeF-actuations are those actuations that result from "valid signals" or from intentional 

manual initiation, unless it is part of a preplanned test. Valid signals are those signals that are 

initiated in response to actual plant conditions or parameters satisfying the requirements for 

initiation of the safety function of the system. Note this definition of "valid" requires that the 

initiation , inal must be an EF signal. This dstintion eliminates actuations They do not 

include those which are the result of other signals from the ,lass of valid atuations. Invalid 

actuations are, by definition, those that do not meet the criteria for being valid. Thus, invalid 

actuations include actuations that are not the result of valid signals and are not intentional 

manual actuations. 

Except for critical scrams, invalid actuations are not reportable by telephone under § 50.72. In 

addition, invalid actuations are not reportable under § 50.73 in any of the following 

circumstances: 

(A) The invalid actuation occurred when the system is already properly removed from service. 

This means all requirements of plant procedures for removing equipment from service have 

been met. It includes required clearance documentation, equipment and control board 

tagging, and properly positioned valves and power supply breakers. 

(B) The invalid actuation occurred after the safety function has already been completed. An 

example would be RPS actuation after the control rods have already been inserted into the 

core. 

If an invalid ESF-actuation reveals a defect in the ESF-system so the system failed or would 

fail to perform its intended function, the event continues to be reportable under other 

requirements of 10 CFR 50.72 and 50.73. When invalid ESF-actuations excluded by the 

conditions described above occur as part of a reportable event, they should be described as 

part of the reportable event, in order to provide a complete, accurate and thorough description 

of the event. 

Examples 

(1) RPS Actuation 

The licensee was placing the residual heat removal (RHR) system in its shutdown 

cooling mode while the plant was in hot shutdown. The BWR vessel level 

decreased for unknown reasons, causing RPS scram and Group III primary 

containment isolation signals, as designed. All control rods had been previously 

inserted and all Group III isolation valves had been manually isolated. The licensee 

isolated RHR to stop the decrease in reactor vessel level. 

An ENS notification and LER are both required because, although the systems' safety 

functions had already been completed, the RPS scram and primary containment 

isolation signals were valid and the actuations were not part of the planned procedure.

49 NUREG-1022, Rev. 2
The automatic signals were valid because they were generated from the sensor by 

measurement of an actual physical system parameter that was at its set point. 

" With the BWR defueled, an invalid signal actuated the RPS. There was no component 

operation because the control rod drive system had been properly removed from 

service. This event is not reportable because (1) the RPS signal was invalid, and (2) 

the system had been properly removed from service. 

" An immediate notification (§ 50.72) 'as r... .. fro. a ,Wl liensee. At a BWR, 

both recirculation pumps tripped as a result of a breaker problem. This placed the plant 

in a condition in which BWRs are generally scrammed to avoid potential power/flow 

oscillations. At this plant, for this condition, a written off-normal procedure required the 

plant operations staff to scram the reactor. The plant staff performed a reactor scram 

which was uncomplicated. 

This event is reportable as a manual RPS actuation. Even though the reactor scram 

was in response to an existing written procedure, this event does not involve a 

preplanned sequence because the loss of recirculation pumps and the resultant off

normal procedure entry were event driven, not preplanned. Both an ENS notification 

and an LER are required. In this case, the licensee initially retracted the ENS 

notification believing that the event was not reportable. After staff review and further 

discussion, it was agreed that the event is reportable for the reasons discussed above. 

(2) BWR Control Rod Block Monitor Actuation 

A rod block that was part of the planned startup procedure occurred from the rod block 

monitor, which, at this plant, is classified as a portion of the RP or as an ESF. 

This event is not reportable because it occurred as a part of a preplanned startup 

procedure that specified certain rod blocks were expected to occur. 

(3) Emergency Diesel Generator (EDG) Starts 

" The " licensee provided an LER, des.ribing an event in which th- An EDG automatically 

started when a technician inadvertently caused a short circuit that de-energized an 

essential bus during a calibration. The actuation was valid because an essential bus 

was de-energized. The event is reportable because the EDG auto-start was not 

identified at the step in the calibration procedure being used. 

" The " lioense provided an LERf describing an event in whieh, After an automatic EDG 

start, and for unknown reasons, the emergency bus feeder breaker from the EDG did 

not close when power was lost on the bus. The event is reportable because the 

actuation logic for the EDG start (E-F actuation at this pla"t) was completed, even 

though the diesel generator did not power the safety buses. 

(4) Preplanned Manual Scram 

During a normal reactor shutdown, the reactor shutdown procedure required that reactor

NUREG-1022, Rev. 2 50
power be reduced to a low power at which point the control rods were to be inserted by a 

manual reactor scram. The rods were manually scrammed. 

This event is not reportable because the manual scram results from and is, by procedure, 

part of a preplanned sequence of reactor operation. However, if conditions develop during 

the process of shutting down that require an unplanned reactor scram, the RPS actuation 

(whether manually or automatically produced) is reportable. 

(5) Actuation of Wrong Component During Testing 

During surveillance testing of the main steam isolation valves (MSIVs), an operator 

incorrectly closed MSIV "D" when the procedure specified closing MSIV "C." 

This event is not reportable because the event is an inadvertent actuation of a single 

component of an EF system rather than a train level actuation (and the purpose of the 

actuation was not to mitigate the consequences of an event). 

"Whole the CV wa e with no testing or maintena". e in progress, a voltage 

transient eauised spiking of a radiation meniter resulting nM isolation of the C)RVS-, as 

designed

This event is not reprtable tundr this criteron beeause the event is due to am inval 

signal and inovsone of the fouir excepted systemns (CflVS). 

(6) Reactor Water Cleanup (RWCU) Isolation 

An RWCU primary containment isolation occurred on pressurization between the RWCU 

suction containment isolation valves, as designed to isolate a pipe break. It is a valid 

signal because this is the safety function of the containment isolation system. Regardless, 

the event is not reportable because the signal did not affect containment isolation valves in 

multiple systems. 

(6) Manual Actuation of-EeSF-Component in Response to Actual Plant Condition 

At a PWR, maintenance personnel inadvertently pulled an instrument line out of a 

compression fitting connection at a pressure transmitter. The resultant reactor coolant 

system (RCS) leak was estimated at between 70 and 80 g.p.m. Charging flow increased 

due to automatic control system action. The operations staff recognized the symptoms of 

an RCS leak and entered the appropriate off-normal procedure. The procedure directed 

the operations staff to start a second charging pump and flow was manually increased to 

raise pressurizer level. Based on the response of the pressurizer level, the operations staff 

determined that a reactor scram and safety injection were not necessary. Maintenance 

personnel still at the transmitter closed the instrument block and root valves terminating the 

event. 

The staff considers the manual start of the charging pump (which also serves as an ECCS

51 NUREG-1022, Rev. 2
pump, but with a different valve lineup) in response to dropping pressurizer level to be an 

intentional manual actuation of an -E- in response to equipment failure or human error 

and reportable because it constitutes deliberate manual actuation of a single component-of 

an ES,, in response to plant conditions, to mitigate the consequences of an event.-As 

indi;ated in the State-.ents of Considerations for the r.es '-As discussed previously in this 

section, actuations that need not be reported are those that are initiated for reasons other 

than to mitigate the consequences of an event (e.g., at the discretion of the licensee as 

part of a planned procedure or evolution). 

(7) ESF-Actuation During Maintenance Activity 

At a BWR, a maintenance activity was under way involving placement of a jumper to 

avoid-ESF unintended actuations. The maintenance staff recognized that there was a 

high potential for a loss of contact with the jumper and consequent ESF-actuation. This 

potential was explicitly stated in the maintenance work request and on a risk evaluation 

sheet. The operating staff was briefed on the potential ESF-actuations prior to start of 

work. During the event, a loss of continuity did occur and the ESF-actuations occurred, 

involving isolation, standby gas treatment start, closing of some valves in the primary 

containment isolation system (recirculation pump seal mini-purge valve, nitrogen supply 

to drywell valve, and containment atmospheric monitoring valve)-oeeuffed. 

The event is not reportable under § 50.72(b)(2)(iv) or (b)(3)(iv) because the actuations 

were not valid. It is reportable under § 50.73(a)(2)(iv) because the actuations were not 

listed as (and were not) definitely expected to occur. 

3.2.7 Event or Condition That Could Have Prevented Fulfillment of a Safety Function

§ 50.72(b)(3)(v) 

"Any event or condition that alone at the 

time of discovery could have prevented the 

fulfillment of the safety function of structures 

or systems that are needed to: 

(A) Shut down the reactor and maintain it 

in a safe shutdown condition; 

(B) Remove residual heat; 

(C) Control the release of radioactive 

material; or 

(D) Mitigate the consequences of an 

accident." 

§ 50.72(b)(3)(vi) 

"Events covered in paragraph (b)(3)(v) of 

this section may include one or more 

procedural errors, equipment failures, and/or

§ 50.73(a)(2)(v) 

"Any event or condition that alonte-could 

have prevented the fulfillment of the safety 

function of structures or systems that are 

needed to: 

(A) Shut down the reactor and maintain it 

in a safe shutdown condition; 

(B) Remove residual heat; 

(C) Control the release of radioactive 

material; or 

(D) Mitigate the consequences of an 

accident." 

§ 50.73(a)(2)(vi) 

"Events covered in paragraph (a)(2)(v) of 

this section may include one or more 

procedural personnel errors, equipment 

failures, and/or discovery of design, analysis,

NUREG-1022, Rev. 2

discovery of desi(gn, analysis, fabrication,

discoverv of design, analysis, fabrication,

52
construction, and/or procedural fabrication, construction, and/or procedural 

inadequacies. However, individual inadequacies. However, individual 

component failures need not be reported component failures need not be reported 

pursuant to paragraph (b)(3)(v) of this pursuant to paragraph (a)(2)(v) of this 

section if redundant equipment in the same section if redundant equipment in the same 

system was operable and available to system was operable and available to 

perform the required safety function." perform the required safety function." 

An LER is required for an event or condition that could have prevented the fulfillment of the 

safety function of structures and systems defined in the rules. If the event or condition could 

have prevented fulfillment of the safety function at the time of discovery, and if it is not 

reported under § 50.72(a), (b)(1), or (b)(2), an ENS notification is required under (b)(3). 

Discussion 

The level of judgment for reporting an event or condition under this criterion is a reasonable 

expectation of preventing fulfillment of a safety function. In the discussions which follow, many 

of which are taken from the Statement of Considerations or from previous NUREG guidance, 

several different expressions such as "would have," "could have," "alone could have," and "reasonable doubt" are used to characterize this standard. In the staff's view, all of these 

should be judged on the basis of a reasonable expectation of preventing fulfillment of the 

safety function. 

As indicated in the Statement of Consoderations, The intent of these criteria is to capture those 

events where there would have been a failure of a safety system to properly complete a safety 

function, regardless of whem the failures were disoverd or whether there was an actual 

demand. For example, if the high pressure safety iniection system (both trains) failed, the 

event would be reportable even if there was no demand for the system's safety function. 

If the event or condition could have prevented fulfillment of the safety function at the time of 

discovery an ENS notification is required. If it could have prevented fulfillment of the safety 

function at any time within three years of the date of discovery an LER is required. 

These criteria cover an event or condition where structures, components, or trains of a safety 

system could have failed to perform their intended function because of: one or more personnel 

errors, including procedure violations; equipment failures; inadequate maintenance; or design, 

analysis, fabrication, equipment qualification, construction, or procedural deficiencies. The 

event must be reported regardless of whether or not an alternate safety system could have 

been used to perform the safety function (e.g., high pressure core cooling failed, but feed and 

bleed or low pressure cre coling were available to provide the safety function of core 

eoe'ing)' For example, if the onsite power system failed the event would be reportable, even if 

the offsite power system remained available and capable of performing the required safety 

function. 

The definition of the systems included in the scope of these criteria is provided in the rules 

themselves. It includes systems required by the TS to be operable to perform one of the four

53 NUREG-1022, Rev. 2
functions (A) through (D) specified in the rule. It is not determined by the phrases "safety

related," "important to safety," or "ESF." 

In determining the reportability of an event or condition that affects a system, it is not 

necessary to assume an additional random single failure in that system; however, it is 

necessary to consider other existing plant conditions. (See Example F41 below). 

The term "safety function" refers to any of the four functions (A through D) listed in these 

reporting criteria that are required during any plant mode or accident situation as described or 

relied on in the plant safety analysis report or required by the regulations. 

A system must operate long enough to complete its intended safety function as defined in the 

safety analysis report. Generic Letter 91-18 provides guidance on determining whether a 

system is operable. Reasonable operator ations to corr.t minor problems maybe 

considered; heer, eroi aetions and unusually perceptive diagnoses, partietlarly duiring 

stressfuil situations, should not be assumed. if a p.tetally serious hum - isade tha 

could have prevented fulfillment of a safety function, but reeovery factors resuilted in the error 

being corrected, the error is still reportable. 

Both offsite electrical power (transmission lines) and onsite emergency power (usually diesel 

generators) are considered to be separate functions by GDC 17. If either offsite power or 

onsite emergency power is unavailable to the plant, it is reportable regardless of whether the 

other system is available. GDC 17 defines the safety function of each system as providing 

sufficient capacity and capability, etc., assuming that the other system is not available. Loss of 

offsite power should be determined at the essential switchgear busses. 

As ind-cated in the Statement of Gon s-ide rations : "The Comm'sin rgni.es that the 

application of this and other paragraphs of this section involves The application of these and 

other reporting criteria involves the use of engineering judgment. In this case, a technical 

judgment must be made whether a failure or operator action that did actually disable one train 

of a safety system, could have, but did not, affect a redundant train within the system. If so, 

this would constitute an event that "could have prevented" the fulfillment of a safety function, 

and, accordingly, must be reported. 

If a component fails by an apparently random mechanism it may or may not be reportable if the 

functionally redundant component could fail by the same mechanism. Reporting is required if 

the failure constitutes a condition where there is reasonable doubt that the functionally 

redundant train or channel would remain operational until it completed its safety function or is 

repaired. For example, if a pump in one train of an ESF system fails because of improper 

lubrication, and engineering judgment indicates that there is a reasonable expectation that the 

functionally redundant pump in the other train, which was also improperly lubricated, would 

have also failed before it completed its safety function, then the actual failure is reportable and 

the potential failure of the functionally redundant pump must be discussed in the LER. 

For systems that include three or more trains, the failure of two or more trains should be

NUREG-1 022, Rev. 2 54
reported if, in the judgment of the licensee, the functional capability of the overall system was 

jeopardized.' 

"Finally, the "--- 1m.ssk.. recognizes that The licensee may also use engineering judgment to 

decide when personnel actions could have prevented fulfillment of a safety function. For 

example, when an individual improperly operates or maintains a component, he might 

conceivably have made the same error for all of the functionally redundant components (e.g., if 

he incorrectly calibrates one bistable amplifier in the Reactor Protection System, he could 

conceivably incorrectly calibrate all bistable amplifiers). However, for an event to be reportable 

it is necessary that the actions actually affect or involve components in more than one train or 

channel of a safety system, and the result of the actions must be undesirable from the 

perspective of protecting the health and safety of the public. The components can be 

functionally redundant (e.g., two pumps in different trains) or not functionally redundant (e.g., 

the operator correctly stops a pump in Train "A" and instead of shutting the pump discharge 

valve in Train "A," he mistakenly shuts the pump discharge valve in Train "B".r-e 

Any time a systemn did not or couild not have performed its safety fuinetion beeauise of a single 

failuire, common mode failuire, or combination of independent failures it is reportable uinde~r 

these riteria. These reporting requirements apply to the system 'evel, rather than the tran or 

eemponent level. 

-Single Failure 

These reporting criteria are not meant to require reporting of a single, independent (~. 

randomn) component failure that makes only one fuinctionally reduindant train inoperative 

uinless it. is indicativife of a generie problem (iLe., has cormmon made failure implieations). 

As indicated in Paragraph 50.73(a)(2)(vi) "...individual component failures need not be 

reported pursuant to this paragraph if redundant equipment in the same system was 

operable and available to perform the required safety function." 

A single failure that defeats the safety function of a redundant system is reportable even if the 

design of the system, which allows such a single failure to defeat the function of the system, 

has been found acceptable. For example, if a single RHR suction line valve should fail in such 

a w~ay that RHR coolin-g cannot be initiated, the event would be reportable. 

As disctssed in the Statement 5onsiderat)o2v, of There are a limited number of single-train 

systems that perform safety functions (e.g., the High Pressure Coolant Injection System in 

BWRs). For such systems, loss of the single train would prevent the fulfillment of the safety 

function of that system and, therefore, is reportable even though the plant technical 

specifications may allow such a condition to exist for a limited time. f i y 

ha FRe 338d acptab 4FoR!3858, July 26, 1983. 

4 18 FR 33851 and 48 FR 33858, July 26, 1983. 

As 18.... FR33851 Jul 261.....'" - Thraralitenubrosnetan

55 NUREG-1 022, Rev. 2
. Common Cause Failures The following conditions are Reportable conditions under these 

criteria include the following: 

"* an event or condition that disabled multiple trains of a system because of a single cause 

"* an event or condition where one train of a system is disabled; in addition, (1) the underlying 

cause that disabled one train of a system could have failed a redundant train and (2) there 

is reasonable expectation that the second train would not complete its safety function if it 

were called upon 

"* an observed or identified event or condition that alone could have prevented fulfillment of 

the safety function 

",Multiple equipment inoperability or u navailabiity Whenever an event or condition exists 

where the system could have been prevented from fulfilling its safety function because of 

one or more reasons for equipment inoperability or unavailability, it is reportable under 

these criteria. This would include cases where one train is disabled and a second train 

fails a surveillance test. 

ilepoability of any of the above ty.ple failures (single, Iommon mode, or multiple) Uinder both

1u GFR 50~.72 and 50.718 sInepaent o; power or plant mode. it also is independent of 

whethen' 

*Imp Oya,~ *1pr o:%P g woLE wi wooI VV A o q oiqI p s, * t, ~ n ~ Af Ao* i A

i Y I•l/ Y 

the systemn or struetsre was required to be operable at the time of diserese 

0 the caiuse of a potential failure of the systems was correted before an actual demand for 

the safety funetion ctld eceur 

M other systems or strutures were available that could have or did perorm the safety 

• fti eeciecopnntta wsdeieed u ntistle 

•the entire system or structure is specified as ErF or safety related 

the problem occurs in a oen safety portion of a system 

The following types of events or conditions generally are not reportable under these criteria: 

" failures that affect inputs or services to systems that have no safety function (unless it 

could have prevented the performance of a safety function of an adjacent or interfacing 

system) 

"w a sinch defective component that was delivered, bunt not installed 

"* removal of a system or part of a system from service as part of a planned evolution for 

maintenance or surveillance testing when done in accordance with an approved procedure 

and the plant's TS (unless a condition is discovered that could have prevented the system 

from performing its function) 

"* independent failure of a single component (unless it is indicative of a generic problem, 

which alone could have caused failure of a redundant safety system failure, or it is in -a 

single train systemn) 

"* a procedure error that could have resulted in defeating the system function but was 

discovered before procedure approval a-d the error 'culd have resulted in defeating the 

syfstern function 

"* a failure of a system used only to warn the operator where no credit is taken for it in any 

safety analysis and it does not directly control any of the safety functions in the criteria

NUREG-1022, Rev. 2 56
"* a single stuck control rod that alone would not have prevented the fulfillment of a reactor 

shutdown 

"* unrelated component failures in several different safety systems 

The applicability of these criteria includes those safety systems designed to mitigate the 

consequences of an accident (e.g., containment isolation, emergency filtration). Hence, minor 

operational events involving a specific component such as valve packing leaks, which could be 

considered a lack of control of radioactive material, should not be reported under this 

paragraph these criteria. System leaks or other similar events may, however, be reportable 

under other sections of the rties criteria.' 

A design or analysis defect or deviation is reportable under this criterion if it could have 

prevented fulfillment of the safety function of structures or systems defined in the rules. 

Reportability of a design or analysis defect or deviation under this criterion should be iudged 

on the same basis that is used for other conditions, such as operator errors and equipment 

failures. That is, the condition is reportable if there is a reasonable expectation of preventing 

fulfillment of the safety function. Alternatively stated, the condition is reportable if there was 

reasonable doubt that the safety function would have been fulfilled if the structure or system 

had been called upon to perform it. 

Examples 

SINGLE TRAIN SYSTEMS 

(1) Failure of a Single-Train System Preventing Accident Mitigation and Residual Heat 

Removal 

When the licensee was preparing to run a surveillance test, a high-pressure coolant 

injection (HPCI) flow controller was found inoperable; therefore, the licensee declared the 

HPCI system inoperable. The plant entered a technical specification requiring that the 

automatic depressurization, low-pressure coolant injection, core spray, and isolation 

condenser systems remain operable during the 7-day LCO or the plant had to be shut 

down. 

The licensee made an ENS notification within 28 minutes and a followup call after the 

amplifier on the HPCI flow transmitter was fixed and the HPCI returned to operability. As 

discussed above, the loss of a single train safety system such as BWR HPCI is reportable. 

(2) Failure of a Single-Train Non-Safety System 

Question: If RCIC is not a "safety system" in that no credit for its operation is taken in the 

safety analysis, are failures and unavailability of this system reportable? 

Answer: If the plant's safety analysis considered RCIC as a system needed to remove 

ridual heat mitiqate a rod eiection accident (e.g., it is included in the Technical 

40v F l 33 5,,,*.w•,,,- -Jul.y 2-'", 1303,.

57 NUREG-1022, Rev. 2
Specifications) then its failure is reportable under this criterion; otherwise, it is not 

reportable under this section of the rule. 

(3) Failure of a Sinqle-Train Environmental System 

Question: There are a number of environmental systems in a plant dealing with such 

things as low level waste (e.g., gaseous radwaste tanks). Many of these systems are not 

required to meet the single failure criterion so a single failure results in the loss of function 

of the system. Are all of these systems covered within the scope of the LER rule? 

Answer: If such systems are required by Technical Specifications to be operational and 

the system is needed to fulfill one of the safety functions identified in this section of the rule 

then system level failures are reportable. If the system is not covered by Technical 

Specifications and is not required to meet the single failure criterion, then failures of the 

system are not reportable under this criterion. 

LOSS OF TWO TRAINS 

(4) Loss of Onsite Emergency Power by Multiple Equipment Inoperability and Unavailability 

During refueling, one emergency diesel generator (EDG) in a two train system was out of 

service for maintenance. The second EDG was declared inoperable when it failed its 

surveillance test. 

An ENS notification is required and an LER is required. As addressed in the Discussion 

section above, loss of either the onsite power system or the offsite power system is 

reportable under this criterion. 

(5) Procedure Error Prevents Reactor Shutdown Function 

The unit was in mode 5 (cold and depressurized; before initial criticality) and a post

modification test was in progress on the train A reactor protection system (RPS), when the 

operator observed that both train A and B source range detectors were disabled. During 

post-modification testing on train A RPS, instrumentation personnel placed the train B input 

error inhibit switch in the inhibit position. With both trains' input error inhibit switches in the 

inhibit position, source range detector voltage was disabled. The input error inhibit switch 

was immediately returned to the normal position and a caution was added to appropriate 

plant instructions. 

This event is reportable because disabling the source range detectors could have 

prevented fulfillment of the safety function to shut down the reactor. 

(6) Failure of the Overpressurization Mitigation System 

The RCS was overpressurized on two occasions during startup following a refueling outage 

because the overpressure mitigation system (OMS) failed to operate. The reason that the 

OMS failed to operate was that one train was out of service for maintenance and a

NUREG-1022, Rev. 2 58
pressure transmitter was isolated and a summator failed in the actuation circuit on the 

other train. 

The event is reportable because the OMS failed to perform its safety function. 

(7) Loss of Salt Water Cooling System and Flooding in Saltwater Pump Bay 

During maintenance activities on the south saltwater pump, the licensee was removing the 

pump internals from the casing when flooding of the pump area occurred. The north 

saltwater pump was secured to prevent pump damage. 

The event is reportable because of the failure of the saltwater cooling system, which is the 

ultimate heat sink for the facility, to perform its safety function. 

(8) Maintenance Affecting Two Trains 

Question: Some clarification is needed for events or conditions that alone-"could have" 

prevented the fulfillment of a system safety function. 

Answer: With regard to maintenance problems, "events or conditions" generally involve 

operator actions and/or component failures that could have prevented the functioning of a 

safety system. For example, assume that a surveillance test is run on a standby pump and 

it seizes. The pump is disassembled and found to contain the wrong lubricant. The 

redundant pump is disassembled and it also has the same wrong lubricant. Thus, it is 

reasonable to assume that the second pump would have failed if it had been challenged. 

However, the second pump and, therefore, the system did not actually fail because the 

second pump was never challenged. Thus, in this case, because of the use of the wrong 

lubricant, the system "could have" or "would have" failed. 

LOSS OF ONE TRAIN 

(9) Oversized Breaker W-r-- g Lugs 

Situiation- Duiring testing of 480) volt safety related breakers, one breaker Would not trip 

eleetrieally. investigation revealed that one wire of the pigtail on the trip eeil, although still 

in its lug, was so loose that there was me electrical connection. The loose connection was 

"due to fapt that the pigtail l..g was too large (No. 14 16 AWG), whereas the pigtai wire 

"ws No. 20 AWG. A No. 18 22 lug is the aeceptable industry standard for a No. 20 AWG 

wire. Since the trip cils were supplied pre-wired, all safety related breakers uitilizing the 

trip cil were inspected. All oth-er breakers inspected had No. 14 16C AWG Itugs. No lugs 

were found with loose eleetrical connections. Nevertheless, all No. 14 16 AWG lugs were 

replaced with acceptable industry Standard Noc. 18 22 AWG Itugs. 

Comnment: The event is reportable because the incompatible pigtails and lugs could have 

caused one or more safety systemns to fail to perform their intended function [58.72(b)(2)(v) 

and 50.73(a)(2)(v)].

59 NUREG-1022, Rev. 2
(9) Contaminated Hydraulic Fluid Degrades MSIV Operation

Situation: During a routine shutdown, the operator noted that the #11 MSIV closing time 

appeared to be excessive. A subsequent test revealed the #11 MSIV shut within the 

required time, however, the #12 MSIV closing time exceeded the maximum at 7.4 sec. 

Contamination of the hydraulic fluid in the valve actuation system had caused the system's 

check valves to stick and delay the transmission of hydraulic pressure to the actuator. 

Three more filters will be purchased providing supplemental filtering for each MSIV. Finer 

filters will be used in pump suction filters to remove the fine contaminants. The #12 MSIV 

was repaired and returned to service. Since the valves were not required for operation at 

the time of discovery, the safety of the public was not affected. 

Comments: The event is reportable under 50.73(a)(2)(v) because a-jtimgf-The condition 

could have prevented fulfillment of a safety function [50.73(a)(2)(-, ]. The fact that the 

eenedotion was diseovered when. the valves were not required for operation does not affect, 

the -eportablit, of the ,,nditon. The event is not reportable under 50.72(b)(3)(v) because, 

at the time of discovery, the plant was shutdown and the MSIV's were not required to be 

operable. 

(10) Diesel Generator Lube Oil Fire Hazard 

Situation: While performing a routine surveillance test of the emergency diesel generator, 

a small fire started due to lubricating oil leakage from the exhaust manifold. The 

manufacturer reviewed the incident and determined that the oil was accumulating in the 

exhaust manifold due to leakage originating from above the upper pistons of this vertically 

opposed piston engine. The oil remaining above the upper pistons after shutdown leaked 

slowly down past the piston rings, into the combustion space, past the lower piston rings, 

through the exhaust ports, and into the exhaust manifolds. The exhaust manifolds became 

pressurized during the subsequent startup which forced the oil out through leaks in the 

exhaust manifold gaskets where it was ignited. Similar events occurred previously at this 

plant. In these previous cases, fuel oil accumulated in the exhaust manifold due to 

extended operation under "no load" conditions. Operation under loaded conditions was 

therefore required before shutdown in order to burn off any accumulated oil. 

Comments: The event is not reportable if the fire did not pose a threat to the plant (e.g., it 

did not significantly hamper site personnel [50.73(a)(2)(ix)]. The event would be reportable 

if it demonstrates a design, procedural, or equipment deficiency that could have prevented 

the fulfillment of a safety function (i.e., if the redundant diesels are of similar design and, 

therefore, susceptible to the same problem) [50.73(a)(2)(vi)]. 

(11) Sinqle Failures 

Question: notice - that loss of relief/safety valve capability is reportable. Does this mean 

that an. LEf- is required when one valve is inoperative? In addton, Suppose you have one 

pump in a cooling water system (e.g., chilled water) supplying water to both trains of a 

safety system, but there is another pump in standby; is the loss of the one operating pump 

reportable?

NUREG-1022, Rev. 2 60
Answer: No. Single, independent (i.e., random) component failures are not reportable as 

L-ERsif the redundant component in the same system did or would have fulfilled the safety 

function. However, if such failures have generic implications, then an LER is to be 

submitted. (See the disc; .... u.der the heading "'ingl. Failures" for further d.s..ss:on 

of reporting the less of one trair.) 

(12) Generic Set-point Drift 

" Situation: With the plant in steady state power operation and while performing a Main 

Steam Line Pressure Instrument Functional Test and Calibration, a switch was found to 

actuate at 853 psig. The Tech Specs limit is 825 +15. The redundant switches were 

operable. The cause of the occurrence was set point drift. The switch was recalibrated 

and tested successfully per HNP-2-5279, Barksdale Pressure Switch Calibration, and 

returned to service. This is a repetitive event as reported in one previous LER. A 

generic review revealed that these type switches are used on other safety systems and 

that this type switch is subject to drift. An investigation will continue as to why these 

switches drift, and if necessary, they will be replaced. 

Comments: The event is not reportable due to the drift of a single pressure switch. 

The event is reportable if it is indicative of a generic and/or repetitive problem with this 

type of switch which is used in several safety systems [50.73(a)(2)(vi) or (vii)]. 

"• Question: Are set point drift problems with a particular switch to be reported if they are 

experienced more than once? 

Answer: The independent failure (e.g., excessive set point drift) of a single pressure 

switch is not reportable unless it could have caused a system to fail to fulfill its safety 

function, or is indicative of a generic problem that could have resulted in the failure of 

more than one switch and thereby cause one or more systems to fail to fulfill their 

safety function. 

(13) Maintenance Affecting Only One Train 

Question: Suppose the wrong lubricant was installed in one pump, but the pump in the 

other train was correctly lubricated. Is this reportable? 

Answer: Engineering judgement is required to decide if the lubricant could have been used 

on the other pump, and, therefore, the system function would have been lost. If the 

procedure called for testing of the first pump before maintenance was performed on the 

second pump and testing clearly identified the error, then the error would not be reportable. 

However, if the procedure called for the wrong lubricant and eventually both pumps would 

have been improperly lubricated, and the problem was only discovered when the first pump 

was actually challenged and failed, then the error would be reportable.

61 NUREG-1022, Rev. 2
OTHER CONDITIONS

(14) Conditions Observed While System Out of Service 

Question: Suppose during shutdown we are doing maintenance on both SI pumps, which 

are not required to be operational. Is this reportable? While shutdown, suppose I identify 

or observe something that would cause the SI pumps not to be operational at power. Is 

this reportable? 

Answer: Removing both SI pumps from service to do maintenance is not reportable if the 

resulting system configuration is not prohibited by the plant's technical specifications. 

However, if a situation is discovered during maintenance that could have caused both 

pumps to fail, (e.g., they are both improperly lubricated) then that condition is reportable 

even though the pumps were not required to be operational at the time that the condition 

was discovered. As another example, suppose the scram breakers were tested during 

shutdown conditions, and it was found that for more than one breaker, opening times were 

in excess of those specified, or that UV trip attachments were inoperative. Such potential 

generic problems are reportable in an LER. 

(15) Diesel Generator Bearing Problems 

During the annual inspection of one standby diesel generator, the lower crankshaft thrust 

bearing and adjacent main bearing were found wiped on the journal surface. The thrust 

bearing was also found to have a small crack from the main oil supply line across the 

journal surface to the thrust surface. Inspection of the second, redundant standby diesel 

generator revealed similar problems. It was judged that extended operation without 

corrective action could have resulted in bearing failure. 

The event is reportable because there was reasonable doubt that the diesels would have 

completed an extended run under load, as required, if called upon. 

(16) Multiple Control Rod Failures 

There have been cases in which licensees have erroneously concluded that not-reported 

mtiltiple-sequentially discovered failures of systems or components occurring during 

planned testing are not reportable. This situation was identified as a generic concern on 

April 13,1985, in NRC Information Notice (IN) 85-27, "Notifications to the NRC Operations 

Center and Reporting Events in Licensee Event Reports," regarding the reportability of 

multiple events in accordance with §§ 50.72(b)(3)(v) and 50.73(a)(2)(v) [event or condition 

that could have prevented fulfillment of a safety function]. 

IN 85-27 described multiple failures of a reactor protection system during control rod 

insertion testing of a reactor at power. One of the control rods stuck. Subsequent testing 

identified 3 additional rods that would not insert (scram) into the core and 11 control rods 

that had an initial hesitation before insertion. The licensee considered each failure as a 

single random failure; thus each was determined not to be reportable. Subsequent 

assessments indicated that the instrument air system, which was to be oil-free, was 

contaminated with oil that was causing the scram solenoid valves to fail. While the failure

NUREG-1022, Rev. 2 62
of a single rod to insert may not cause a reasonable doubt that-about the ability of other 

rods wetldukail-to insert, the failure of more than one rod does cause a reasonable doubt 

that other rods .c.'ld be aff e.ted, thus affe-ting the safety function of the rods. 

As indicated in IN 85-27, multiple failures of redundant components of a safety system are 

sufficient reason to expect that the failure mechanism, even though not known, could have 

prevented the fulfillment of the safety function. 

(17) Potential Loss of High Pressure Coolant Iniection 

During normal refueling leak testing of the upstream containment isolation check valve on 

the High Pressure Coolant Injection (HPCI) steam exhaust, the disc of the non-containment 

isolation check valve was found lodged in downstream piping. This might have prevented 

HPCI from functioning if the disc had blocked the line. The event was caused by fatigue 

failure of a disc pin. 

Following evaluation of the condition, the event was determined to be reportable because 

the HPCI could have been prevented from performing its safety function if the disc had 

blocked the line. In addition, the event is reportable if the fatigue failure is indicative of a 

common-mode failure. 

(18) Defective Comnponent Delivered but not Installed 

Question: 1 low shouild a plant report a defective comnponent that was delivered, but not 

instaH'eeI 

Answer A single defective comnponent would not generally be report~able (assuminig that 

the problem has no generic implications). A generic problemn or a nuimber of defective 

eemponents would probably constituite a condition that culd have prevented fulfillment of 

a safety function, and, Of so, would be reportable. Engineering judgment is required to. 

determine if the defects eould have escaped detection prior to installation and operation. 

As a minm, an 1 generic problem may be reported as a voluntary LEfl. in addition, suich 

a ondition may be reo -beuder 10 CmR Part 21. 

(18) Operator Inaction or Wrong Action 

Question: In some systems used to control the release of radioactivity, a detector controls 

certain equipment. In other systems, a monitor is present and the operator is required to 

initiate action under certain conditions. The operator is not "wired" in. Are failures of the 

operator to act reportable? 

Answer: Yes. The operator may be viewed as a "component" that is an integral, and 

frequently essential, part of a "system." Thus, if an event or condition meets the reporting 

criterion specified in 50.73 for reporting, it is to be reported regardless of the initiating 

cause. (i.e., whether an e ipent, procedure, or personnel error is involved).

63 NUREG-1022, Rev. 2
(19) Results of Analysis

Question: A number of criteria indicate that they apply to actual situations only and not to 

potential situations identified as a result of analysis; yet, other criteria address "could 

have." When do the results of analysis have to be reported? 

Answer: The results need only to be reported if the applicable criterion requires the 

reporting of conditions that "could have" caused a problem. However, others have a need 

to know about potential problems that are not reportable; thus, such items may be reported 

as a voluntary LER. 

(20) System Interactions 

Question: Utilities are not required to analyze for system interactions, yet the rule requires 

the reporting of events that "could have" happened but did not. Are we to initiate a design 

activity to determine "could have" system interactions? 

Answer: No. Report system interactions that you find as a result of ongoing routine 

activities (e.g., the analysis of operating events). 

3.2.8 Common-cause Inoperability of Independent Trains or Channels

§ 50.72 

There is no 

corresponding 

requirement in 

§ 50.72.

§ 50.73(a)(2)(vii) 

"Any event where a single cause or condition caused at least 

one independent train or channel to become inoperable in multiple 

systems or two independent trains or channels to become 

inoperable in a single system designed to: 

(A) Shut down the reactor and maintain it in a safe shutdown 

condition; 

(B) Remove residual heat; 

(C) Control the release of radioactive material; or 

(D) Mitigate the consequences of an accident."

An LER is required for a common cause inoperability of independent trains or channels. 

Discussion 

This criterion requires those events to be reported where a single cause or condition caused 

independent trains or channels to become inoperable. Common-causes may include such 

factors as high ambient temperatures, heat up from energization, inadequate preventive 

maintenance, oil contamination of air systems, incorrect lubrication, use of non-qualified 

components or manufacturing or design flaws. The event is reportable if the independent 

trains or channels were inoperable at the same time, regardless of whether or not they were

NUREG-1022, Rev. 2 64
discovered at the same time. (Example (2) below illustrates a case where the second failure 

was discovered 3 days later than the first.) 

An event or failure that results in or involves the failure of independent portions of more than 

one train or channel in the same or different systems is reportable. For example, if a cause or 

condition caused components in Train "A" and "B" of a single system to become inoperable, 

even if additional trains (e.g., Train "C") were still available, the event must be reported. In 

addition, if the cause or condition caused components in Train "A" of one system and in Train 

"B" of another system (i.e., train that is assumed in the safety analysis to be independent) to 

become inoperable, the event must be reported. However, if a cause or condition caused 

components in Train "A" of one system and Train "A" of another system (i.e., trains that are not 

assumed in the safety analysis to be independent), the event need not be reported unless it 

meets one or more of the other reporting criteria. 

Trains or channels for reportability purposes are defined as those redundant, independent 

trains or channels designed to provide protection against single failures. Many engineered 

safety systems containing active components are designed with at least a two-train system. 

Each independent train in a two-train system can normally satisfy all the safety system 

requirements to safely shut down the plant or satisfy those criteria that have to be met 

following an accident. 

This criterion does not include those cases where one train of a system or a component was 

removed from service as part of a planned evolution, in accordance with an approved 

procedure, and in accordance with the plant's technical specifications. For example, if the 

licensee removes part of a system from service to perform maintenance, and the Technical 

Specifications permit the resulting configuration, and the system or component is returned to 

service within the time limit specified in the Technical Specifications, the action need not be 

reported under this paragraph. However, if, while the train or component is out of service, the 

licensee identifies a condition that could have prevented the whole system from performing its 

intended function (e.g., the licensee finds a set of relays that is wired incorrectly), that 

condition must be reported. 

Analysis of events reported under this part of the rule may identify previously unrecognized 

common-cause (or dependent) failures and system interactions. Such failures can be 

simultaneous failures that occur because of a single initiating cause (i.e., the single cause or 

mechanism serves as a common input to the failures); or the failures can be sequential (i.e., 

cascading failures), such as the case where a single component failure results in the failure of 

one or more additional components. 

Examples 

(1) Incorrect Lubrication Degrades Main Steam Isolation Valve Operation 

During monthly operability tests, the licensee found that the Unit 2B inboard MSIV did not 

stroke properly as a result of a solenoid-operated valve (SOV) failure. Both units were shut 

down from 100-percent power, and the SOVs piloting all 16 MSIVs were inspected. The 

licensee found that the SOVs on all 16 MSIVs were damaged. The three-way and four

way valves and solenoid pilot valves on all 16 MSIVs had a hardened, sticky substance in

65 NUREG-1022, Rev. 2
their ports and on their O-rings. As a result, motion of all the SOVs was impaired, resulting 

in instrument air leakage and the inability to operate all of the MSIVs satisfactorily. The 

licensee also examined unused spares in the warehouse and found that the lubricant had 

dried out in those valves, leaving a residue. Several of the warehouse spares were bench 

tested. They were found to be degraded and also leaked. The root cause of the event 

was use of an incorrect lubricant. 

The event is reportable (a) because a single cause or condition caused multiple 

independent trains of the main steam isolation system (a system designed to control the 

release of radioactive material and mitigate the consequences of an accident) to become 

inoperable [§ 50.73(a)(2)(vii)(C and D)] and (b) because a single condition could have 

prevented fulfillment of a safety function [§ 50.73(a)(2)(v)]. 

(2) Marine Growth Causing Emergency Service Water To Become Inoperable (Common-Mode 

Failure Mechanism) 

With Unit 1 at 74 percent power and Unit 2 at 100 percent power, ESW pump 1A was 

declared inoperable because its flow rate was too low to meet acceptance criteria. Three 

days later, with both units at the same conditions, ESW pump 1C was declared inoperable 

for the same reason. The ESW pumps provide the source of water from the intake canal 

during a design-basis accident. In both cases, the cause was marine growth of hydroids 

and barnacles on the impeller and suction of the pumps. Following maintenance, both 

pumps passed their performance tests and were placed in service. Pump testing 

frequency was increased to more closely monitor pump performance. 

This event is reportable because a single cause or condition caused two independent 

trains to become inoperable in a single system designed to mitigate the consequences of 

an accident [§ 50.73(a)(2)(vii)(D)]. 

(3) Testing Indicated Several Inoperable Snubbers 

The licensee found 11 inoperable snubbers during periodic testing. All the snubbers failed 

to lock up in tension and/or compression. These failures did not render their respective 

systems inoperable, but rendered trains inoperable. Improper lockup settings and/or 

excessive seal bypass caused these snubbers to malfunction. These snubbers were 

designed for low probability seismic events. Numerous previous similar events have been 

reported by this licensee. 

This condition is reportable because the condition indicated a generic common-mode 

problem that caused numerous multiple independent trains in one or more safety systems 

to become inoperable. The potential existed for numerous snubbers in several systems to 

fail following a seismic event rendering several trains inoperable. [§ 50.73(a)(2)(vii)] 

(4) Stuck High-Pressure Iniection (HPI) System Check Valves as a Result of Corroded 

Flappers 

The licensee reported that check valves in three of four HPI lines were stuck closed. The 

unit had been shut down for refueling and maintenance.

NUREG-1022, Rev. 2 66
A special test of the check valves revealed that three stop check valves failed to open 

when a differential pressure up to the capacity of the pump was applied. Further review 

showed that the common cause of valve failure was the flappers corroding shut. 

The event is reportable because a single cause or condition caused at least two 

independent trains of the HPI system to become inoperable. This system is designed to 

remove residual heat and mitigate the consequences of an accident. The condition is 

therefore reportable under 50.73(a)(2)(vii)(B and D), common cause failure in systems 

designed to remove residual heat and mitigate accidents. 

3.2.9 Radioactive Release

§ 50.72 

The corresponding requirement in § 50.72 

has been deleted. 

Refer to the plant's Emergency Plan 

regarding declaration of an Emergency 

Class. 

Refer to § 50.72(b)(2)(xi) below 

regarding a news release or notification of 

another agency. 

Refer to § 20.2202 regarding events 

reportable under that section.

§ 50.73(a)(2)(viii) 

"(A) Any airborne radioactivity release 

that, when averaged over a time period of 1 

hour, resulted in airborne radionuclide 

concentrations in an unrestricted area that 

exceeded 20 times the applicable 

concentration limits specified in Appendix B 

to Part 20, Table 2, Column 1. 

(B) Any liquid effluent release that, when 

averaged over a time period of 1 hour, 

exceeds 20 times the applicable 

concentrations specified in Appendix B to 

Part 20, Table 2, Column 2, at the point of 

entry into the receiving waters (i.e., 

unrestricted area) for all radionuclides 

except tritium and dissolved noble gases." 

-. .L-..:C. M" A&~ 4L, t-6 * |I 1 JlI L. ),.,Lu IIIIllUL LU Li V '.dJI I II111 .ITFIT R

, V .I.c -, 4 m, -'•,-. JI aji!J) UI

An LER is required for a release as defined in the rules. 

Discussion 

Although similar to 10 CFR 20.2202 and 20.2203, these criteria place a lower threshold for 

reporting events at commercial power reactors because the significance of the breakdown of 

the licensee's program that allowed such a release is the primary concern, rather than the 

significance of the effect of the actual release. In contrast, however, the time limit for reporting 

under 10 CFR 20.2202 and 20.2203 is more restrictive.

NUREG-1022, Rev. 2

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For a release that takes less than 1 hour, normalize the release to 1 hour (e.g., if the release 

lasted 15 minutes, divide by 4). For releases that lasted more than 1 hour, use the highest 

release for any continuous 60-minute period (i.e., comparable to a moving average). 

Annual average meteorological data should be used for determining offsite airborne 

concentrations of radioactivity to maintain consistency with the technical specifications (TS) for 

reportability thresholds. 

The location used as the point of release for calculation purposes should be determined using 

the expanded definition of an unrestricted area as specified in NUREG-0133 ("Preparation of 

Radiological Effluent Technical Specifications for Nuclear Power Plants," October 1978) to 

maintain consistency with the TS. 

If estimates determine that the release has exceeded the reporting criterion, an ENS 

notification is required, followed up by a more precise estimate in the LER. If it is later 

determined that the release was less than this criterion, the ENS notification may be retracted. 

As indicated in Generic Letter 85-19, September 27, 1985, "Reporting Requirements on 

Primary Coolant Iodine Spikes," primary coolant iodine spike releases need not be reported on 

a short term basis. 

Examples 

(1) Unmonitored Release of Contaminated Steam Through Auxiliary Boiler Atmospheric Vent 

An unmonitored release of contaminated steam resulted from a combination of a tube leak, 

improper venting of an auxiliary boiler system, and inadequate procedures. This 

combination resulted in a release path from a liquid waste concentrator to the atmosphere 

via the auxiliary boiler system steam drum vent. 

Because of rain at the site, the steam release to the atmosphere was condensed and 

deposited onto plant buildings and yard areas. This contamination was washed via a storm 

drain into a lake. The release was later confirmed to be 2.6 E-5 pCi/ml of Cs-1 37 at the 

point of entry into the receiving water. 

An LER is required as a liquid radioactive material release because the unmonitored 

release exceeded 20 times the applicable concentrations specified in Table 2, Column 2 of 

Appendix B to 10 CFR Part 20, averaged over 1 hour at the site boundary. 

(2) Unplanned Gaseous Release 

During routine scheduled maintenance on a pressure actuated valve in the gaseous waste 

system, an unplanned radioactive release to the environment was detected by a main 

stack high radiation alarm. The release occurred when an isolation valve, required to be 

closed on the station tag out sheet, was inadvertently left open. This allowed radioactive 

gas from the waste gas decay tank to escape through a pressure gage connection that had 

been opened to vent the system. Operator error was the root cause of this release, with 

ambiguous valve tag numbers as a contributing factor. The concentration in the

NUREG-1 022, Rev. 2 68
unrestricted area, averaged over 1 hour, was estimated by the licensee to be 1 E-5 pCi/mI 

of Kr-85 and 5 E-6 pCi/ml of Xe-133. 

The event was reportable via an LER because the sum of the ratios of the concentration of 

each airborne radionuclide in the restricted area when averaged over a period of 1 hour, to 

its respective concentration specified in Table 2, Column 1 of Appendix B to 10 CFR 20, 

exceeds 20. 

3.2.10 Internal Threat or Hampering 

§ 50.72 § 50.73(a)(2)(x) 

The corresponding requirement in "Any event that posed an actual threat 

§ 50.72 has been deleted, to the safety of the nuclear power plant or 

Refer to the plant's Emergency Plan significantly hampered site personnel in the 

regarding declaration of an Emergency performance of duties necessary for the 

Class. safe operation of the nuclear power plant 

including fires, toxic gas releases, or 

radioactive releases." 

An LER is required for an event that poses an actual threat or causes significant hampering, 

as defined in the rules. 

Discussion 

These criteria pertain to internal threats. The criterion for external threats, § 50.73(a)(2)(iii), is 

described in Section 3.2.5 of this report. 

This provision requires reporting events, particularly those caused by acts of personnel, which 

endanger the safety of the plant or interfere with personnel in the performance of duties 

necessary for safe plant operations. 

The licensee must exercise some judgment in reporting under this rule. For example, a small 

fire on site that did not endanger any plant equipment and did not and could not reasonably be 

expected to endanger the plant is not reportable. 

The phrase "significantly hampers site personnel" applies narrowly, i.e. only to those events 

which significantly hamper the ability of site personnel to perform safety-related activities 

affecting plant safety. 

In addition, the staff considers the following standards appropriate in this regard: 

* The significant hampering criterion is pertinent to "the performance of duties necessary for 

safe operation of the nuclear power plant." One way to evaluate this is to ask if one could 

seal the room in question (or disable the function in question) for a substantial period of

69 NUREG-1022, Rev. 2
time and still operate the plant safely. For example, if a switchgear room is unavailable for 

a time, but it is normally not necessary to enter the room for safe operation, and no need to 

enter the room arises while it is unavailable, the event is not reportable under this criterion. 

"* Significant hampering includes hindering or interfering (su•h as with protective ,lothing or 

radiation work perits) provided that the interference or delay is sufficient to significantly 

threaten the safe operation of the plant. 

"* Actions such as room evacuations that are precautionary would not constitute significant 

hampering if the necessary actions can still be performed in a timely manner. 

Plant mode may be considered in determining if there is an actual internal threat to a plant. 

However, licensees should not incorrectly assume that everything that happens while a plant is 

shut down is unimportant and not reportable. 

In-plant releases must be reported if they require evacuation of rooms or buildings and, as a 

result, the ability of the operators to perform duties necessary for safe operation of the plant is 

significantly hampered. 

Events such as minor spills, small gaseous waste releases, or the disturbance of contaminated 

particulate matter (e.g., dust) that require temporary evacuation of an individual room until the 

airborne concentrations decrease or until respiratory protection devices are used, are not 

reportable unless the ability of site personnel to perform necessary safety functions is 

significantly hampered. 

No LER is required for precautionary evacuations of rooms and buildings that subsequent 

evaluation determines were not required. Even if an evacuation affects a major part of the 

facility, the test for reportability is whether an actual threat to plant safety occurred or whether 

site personnel were significantly hampered in carrying out their safety responsibilities. 

In most cases, fires result in ENS notification because there is a declaration of an emergency 

class, which is reportable under § 50.72(a)(1 )(i) as discussed in Section 3.1.1 of this report.13 

If there is an actual threat or significant hampering, an LER is also required. With regard to 

control room fires, the staff generally considers a control room fire to constitute an actual threat 

and significant hampering.14 

Examples 

(1) Fire in Refueling Bridge 

Question: If we have a fire in the refueling bridge and we are not moving fuel, would the 

13 As indicated in NUREG-0654, Rev. 1, Information Notice 88-64 and Regulatory Guide 1.101, Rev. 3 

(which endorses NUMARC/NESP-007, Rev. 2), a fire that lasts longer than 10 or 15 minutes or which affects plant 

equipment important for safe operation would result in declaration of an emergency class. 

14 It is theoretically possible to have a control room fire which is discovered and extinguished quickly and, 

even in this location, does not significantly hamper the operators and does not threaten plant safety. Examples 

could include small paper fires in ash trays or trash cans, or cigarette bums of furniture or upholstery.

NUREG-1022, Rev. 2 70
fire be reportable?

Answer: No. If the plant is not moving fuel and the fire does not otherwise threaten other 

safety equipment and does not hamper site personnel, the fire is not reportable. If the 

plant is moving fuel, the fire is reportable. 

(2) Fire in Reactor Building 

Question: If we have a fire in the reactor building that forces contractor personnel who are 

doing a safety related modification to leave, but the fire did not hamper operations 

personnel or equipment, would that fire be reportable? 

Answer: No. The fire would not be reportable if the fire was not severe enough that it 

posed an actual threat to the plant and the delay in completing the modification did not 

significantly threaten the safe operation of the plant. 

3.2.11 Transport of a Contaminated Person Offsite 

§ 50.72(b)(3)(xii) § 50.73 

"Any event requiring the transport of a There is no corresponding requirement 

radioactively contaminated person to an in § 50.73. 

offsite medical facility for treatment." 

If not reported under § 50.72(a), (b)(1), or (b)(2), an ENS notification is required under (b)(3) 

[an 8-hour report] for transport of a radioactively contaminated person to an offsite medical 

facility for treatment. 

Discussion 

The phrase "radioactively contaminated" refers to either radioactively contaminated clothing 

and/or person. If there is a potential for contamination (e.g., an initial onsite survey for 

radioactive contamination is required but has not been completed before transport of the 

person off site for medical treatment) the licensee should make an ENS notification. See the 

example. 

No LER is required for transporting a radioactively contaminated person to an offsite medical 

facility for treatment. 

Example 

Radioactively Contaminated Person Transported Offsite for Medical Treatment 

A contract worker experienced a back injury lifting a tool while working in a contaminated 

area and was considered potentially contaminated because his back could not be

71 NUREG-1022, Rev. 2
surveyed. Health physics (HP) technicians accompanied the worker to the hospital. The 

licensee made an ENS notification immediately and an update notification after clothing, 

but not the individual, was found to be contaminated. The HP technicians returned to the 

plant with the contaminated protective clothing worn by the worker. 

An ENS notification is required because of the transport of a radioactively contaminated 

person to an offsite medical facility for treatment. 

3.2.12 News Release or Notification of Other Government Agency 

§ 50.72(b)(2)(xi) § 50.73 

"Any event or situation, related to the health and There is no corresponding 

safety of the public or on-site personnel, or protection of requirement in § 50.73. 

the environment, for which a news release is planned or 

notification to other government agencies has been or 

will be made. Such an event may include an on-site 

fatality or inadvertent release of radioactively 

contaminated materials." 

If not reported under § 50.72(a) or (b)(1), licensees are required to notify the NRC via the ENS 

under (b)(2) [a 4-hour report]. 

Discussion 

The purpose of this criterion is to ensure the NRC is made aware of issues that will cause 

heightened public or government concern related to the radiological health and safety of the 

public or on-site personnel or protection of the environment. 

Licensees typically issue press releases or notify local, county, State or Federal agencies on a 

wide range of topics that are of interest to the general public. The NRC Operations Center 

does not need to be made aware of every press release made by a licensee. The following 

clarifications are intended to set a reporting threshold that ensures necessary reporting, while 

minimizing unnecessary reporting. 

Examples of events likely to be reportable under this criterion include 

"* release of radioactively contaminated tools or equipment to public areas 

"• unusual or abnormal releases of radioactive effluents 

"• onsite fatality 

Licensees generally do not have to report media and government interactions unless they are 

related to the radiological health and safety of the public or onsite personnel, or protection of 

the environment. For example, the NRC does not generally need to be informed under this 

criterion of:

NUREG-1022, Rev. 2 72
"* minor deviations from sewage or chlorine effluent limits 

"* minor non-radioactive, onsite chemical spills "• minor oil spills 

"* problems with plant stack or water tower aviation lighting 

"* peaceful demonstrations 

"* routine reports of effluent releases to other agencies 

"* releases of water from dams associated with the plant 

Press Release 

The NRC has an obligation to inform the public about issues within the NRC's purview that 

affect or raise a concern about the public health and safety. Thus, the NRC needs accurate, 

detailed information in a timely manner regarding such situations. The NRC should be aware 

of information that is available for the press or other government agencies. 

However, the NRC need not be notified of every press release a licensee issues. The field of 

NRC interest is narrowed by the phrase "related to the health and safety of the public or onsite 

personnel, or protection of the environment," in order to exclude administrative matters or 

those events of no significance. 

Routine radiation releases are not specifically reportable under this criterion. However, if a 

release receives media attention, the release is reportable under this criterion. 

If possible, licensees should make an ENS notification before issuing a press release because 

news media representatives will usually contact the NRC public affairs officer shortly after its 

issuance for verification, explanation, or interpretation of the facts. 

Other Government Notifications 

For reporting purposes, "other government agencies" refers to local, State or other Federal 

agencies. 

Notifying another Federal agency does not relieve the licensee of the requirement to report to 

the NRC. 

Some plants provide a State incident response facility with alarm indication coincident with 

control room alarms, e.g., an effluent radiation monitor alarm. However, an alarm received at a 

State facility is in itself not a requirement for notifying the NRC under this criterion. A release 

is reportable under this criterion if a press release is planned or a specific report (beyond the 

automatic alarm indication) has been or will be made to a State agency. 

Examples 

(1) Onsite Drowning Government Notifications and Press Release 

A boy fell into the discharge canal while fishing and failed to resurface. The licensee 

notified the local sheriff, State Police, U.S. Coast Guard and State emergency agencies.

73 NUREG-1022, Rev. 2
Local news agencies were granted onsite access for coverage of the event. The licensee 

notified the NRC resident inspector. 

As ENS notification is needed because of the fatality on-site, the other government 

notifications made, and media involvement. 

(2) Licensee Media Inquiries Regarding NRC Findings 

As a result of a local newspaper article regarding the findings of an NRC regional 

inspection of the 10 CFR Part 50, Appendix R, Fire Protection Program, a licensee 

representative was interviewed on local television and radio stations. The licensee notified 

State officials and the NRC resident inspector. 

The staff does not consider an ENS notification to be needed because the subject of the 

radio and TV interviews was an NRC inspection. 

(3) County Government Notification 

The licensee informed county governments and other organizations of a spurious actuation 

of several emergency response sirens in a county (for about 5 minutes according to county 

residents). The licensee also planned to issue a press release. 

An ENS notification is needed because county agencies were notified regarding the 

inadvertent actuation of part of the public notification system. Such an event also would be 

reportable if the county informs the licensee of the problem because of the concern of the 

public for their radiological health and safety. 

(4) State Notification of Unscheduled Radiation Release 

The licensee reported to the State that they were going to release about 50 curies of 

gaseous radioactivity to the atmosphere while filling and venting the pressurizer. The 

licensee then revised their estimate of the release to 153 curies. However, since the 

licensee had not informed the State within 24 hours of making the release, they had to 

reclassify the release as "unscheduled" per their agreement with the State. The licensee 

notified the State and the NRC resident inspector. 

An ENS notification is needed because of the State notification of an "unscheduled" 

release of gaseous radioactivity. The initial notification to the State of the scheduled 

release does not need an ENS notification because it is considered as a routine 

notification. 

(5) State Notification of Improper Dumping of Radioactive Waste 

The licensee transported two secondary side filters to the city dump as nonradioactive 

waste but later determined they were radioactive. The dump site was closed and the filters 

retrieved. The licensee notified the appropriate State agency and the NRC resident 

inspector.

NUREG-1022, Rev. 2 74
An ENS notification is needed because of the notification to the State agency of the 

inadvertent release of radioactively contaminated material off site, which affects the 

radiological health and safety of the public and environment. 

(6) Reports Regarding Endangered Species 

The licensee notified the U.S. Fish & Wildlife Service and a State agency that an 

endangered species of sea turtle was found in their circulating water structure trash bar. 

No press release was planned. 

An ENS notification is required because of the notification of state and federal agencies 

regarding the taking of an endangered species. (The NRC has statutory responsibilities 

regarding protection of endangered species.) 

(7) Routine Agency Notifications 

A licensee notified the U.S. Environmental Protection Agency (EPA) that the circulation 

water temperature rise exceeded the release permit allowable. This event was caused by 

the unexpected loss of a circulating water pump while operating at 92-percent power. The 

licensee reduced power to 73 percent so that the circulating water temperature would 

decrease to within the allowable limits until the pump could be repaired. 

A licensee notified the Federal Aviation Agency that it removed part of its auxiliary boiler 

stack aviation lighting from service to replace a faulty relay. 

A licensee notified the State, EPA, U.S. Coast Guard and Department of Transportation 

that 5 gallons of diesel fuel oil had spilled onto gravel-covered ground inside the protected 

area. The spill was cleaned up by removing the gravel and dirt. 

The staff does not consider an ENS notification to be needed because these events are 

routine and have little significance. 

3.2.13 Loss of Emergency Preparedness Capabilities 

§ 50.72(b)(3)(xiii) § 50.73 

"Any event that results in a major loss of emergency There is no corresponding 

assessment capability, offsite response capability, or requirement in § 50.73. 

offsite communications capability (e.g., significant portion 

of control room indication, Emergency Notification 

System, or offsite notification system)." 

If not reported under § 50.72(a), (b)(1) or (b)(2), an ENS notification is required under (b)(3) for 

a major loss of their emergency assessment, offsite response, or communications capability.

75 NUREG-1022, Rev. 2
Discussion

This reporting requirement pertains to events that would impair a licensee's ability to deal with 

an accident or emergency. Notifying the NRC of these events may permit the NRC to take 

some compensating measures and to more completely assess the consequences of such a 

loss should it occur during an accident or emergency. 

Examples of events that this criterion is intended to cover are those in which any of the 

following is not available: 

"* Safety parameter display system (SPDS) 

"* Emergency response facilities (ERFs) 

"* Emergency communications facilities and equipment including the emergency notification 

system (ENS) 

"* Public prompt notification system including sirens 

"* Plant monitors necessary for accident assessment 

These and other situations should be evaluated for reportability as discussed below. 

Loss of Emergency Assessment Capability 

A major loss of emergency assessment capability would include those events that significantly 

impair the licensee's safety assessment capability. Some engineering judgment is needed to 

determine the significance of the loss of particular equipment, e.g., loss of only the SPDS for a 

short period of time need not be reported, but loss of SPDS and other assessment equipment 

at the same time may be reportable. 

The staff considers the loss of a significant portion of control room indication including 

annunciators or monitors, or the loss of all plant vent stack radiation monitors, as examples of 

a major loss of emergency assessment capability which should be evaluated for reportability. 

Loss of Offsite Response Capability 

A major loss of offsite response capability includes those events that would significantly impair 

the fulfillment of the licensee's approved emergency plan for other than a short time. Loss of 

offsite response capability may typically include the loss of plant access, emergency offsite 

response facilities1 5, or public prompt notification system, including sirens and other alerting 

systems. 

If a significant natural hazard (e.g., earthquake, hurricane, tornado, flood, etc.) or other event 

causes evacuation routes to be impassible or other parts of the response infrastructure to be 

15 Performing maintenance on an offsite emergency response facility is not reportable if the facility can be 

returned to service promptly in the event of an accident.

NUREG-1 022, Rev. 2 76
impaired to the extent that the State and local governments are rendered incapable of fulfilling 

their responsibilities in the emergency plan for the plant, then the NRC must be notified. This 

does not apply in the case of routine traffic impediments such as fog, snow and ice which do 

not render the state and local governments incapable of fulfilling their responsibilities. It is 

intended to apply to more significant cases such as the conditions around the Turkey Point 

plant after Hurricane Andrew struck in 1992 or the conditions around the Cooper station during 

the Midwest floods of 1993. 

If the alert systems, e.g., sirens, are owned and/or maintained by others, the licensee should 

take reasonable measures to remain informed and must notify the NRC if a large number of 

sirens fail. Although the loss of a single siren for a short time is not a major loss of offsite 

response capability, the loss of a large number of sirens, other alerting systems (e.g., tone 

alert radios), or more importantly, the lost capability to alert a large segment of the population 

for 1 hour would warrant an immediate notification. 

Loss of Communications Capability 

A major loss of communications capability may include the loss of ENS, HPN and/or other 

offsite communication systems. The other offsite communication systems may include a 

dedicated telephone communication link to a State or a local government agency and 

emergency offsite response facilities, in-plant paging and radio systems required for safe plant 

operation, or commercial telephone lines. 

NRC Regulatory Issue Summary 2000-11, June 30, 2000, discusses the NRC Emergency 

Telecommunications System (ETS). The ETS provides seven communication functions to 

nuclear power reactor emergency response facilities. Included in these functions are the ENS, 

the Health Physics Network (HPN) and the ERDS. ETS service is currently provided using 

direct access lines to the Federal Government's long distance network, FTS 2000. These 

dedicated lines provide a direct connection to FTS 2000 and are not switched at the local 

central office. In the future, the Federal Government will adopt a new long distance network, 

FTS 2001. ETS functions will either be provided by the NRC in the form of direct access lines 

to the Federal Government's new long distance network, FTS 2001, or, alternatively, by 

licensee telecommunications capabilities that provide access to long distance networks without 

swithcing at the local central office. 

Shouild If FTS 2001 is used to provide ETS functionality at a site and either or both of the 

emergency communications subsystems (ENS and HPN) fail, the NRC Operations Center 

should be so informed over normal commercial telephone lines. When notifying the NRC 

Operations Center, licensees should use the backup commercial telephone numbers provided. 

This satisfies the guidance provided in previous Information Notices 85-44 "Emergency 

Communication System Monthly Test," dated May 30, 1985 and 86-97 "Emergency 

Communications System," dated November 28, 1986, to test the backup means of 

communication when the primary system is unavailable as well as the reporting requirements 

of § 50.72(b)(2)(xii). If the Operations Center notifies the licensee that an ENS line is 

inoperable, there is no need for a subsequent licensee notification. Loss of either ENS or 

HPN does not generate an event report. The Operations Center contacts the appropriate 

repair organization.

77 NUREG-1022, Rev. 2
In a similar manner, if the NRC supplied telephone line or modem used for ERDS is 

inoperable, the NRC operations center should be informed so that repairs can be ordered. 

However, this does not generate an event report. 

If ETS functionality is provided using licensee corporate communications systems, the NRC 

Operations Center should be informed through any means available of any communication 

system failures which render ETS communication functions unavailable. This does not apply 

to minor interruptions in portions of the site or corporate telecommunications systems. It is 

intended to apply to serious conditions during which the telecommunications system can no 

longer fulfill the communications requirements of the emergency plan or provide ETS 

functionality. 

Examples 

(1) Loss of Public Prompt Notification System 

ENS notifications of the loss of the emergency sirens or tone alert radios vary according to 

the licensee's locale and interpretations of "major loss" and have included: 

• 12 of 40 county alert sirens disabled because of loss of power as a result of severe 

weather. 

* 28 of 54 alert sirens were reported out of service as a result of a local ice storm. 

* All offsite emergency sirens were: 

- found inoperable during a monthly test. 

- taken out of service for repair. 

- inoperable because control panel power was lost. 

- inoperable because the county radio transmitter failed. 

An ENS notification is required because of the major loss of offsite response capability, 

i.e., the public prompt notification system. However, licensees may use engineering 

judgment in determining reportability (i.e., a "major loss") based upon such factors as the 

percent of the population not covered by emergency sirens and the existence of 

procedures or practices to compensate for the lost emergency sirens. An LER is not 

required because there are no corresponding 10 CFR 50.73 requirements. 

(2) Loss of ENS and Commercial Telephone System 

The licensee determined that ENS and commercial telecommunications capability was lost 

to the control room when a fiber optic cable was severed during maintenance. A 

communications link was established and maintained between the site and the load 

dispatcher via microwave transmission. Both the ENS and commercial communications 

capability were restored approximately 90 minutes later. 

An ENS notification is required because of the major loss of communications capability. 

Although the microwave link to the site was established and maintained during the

NUREG-1022, Rev. 2 78
telephone outage, this in itself does not fully compensate for the loss of communication 

that would be required in the event of an emergency at the plant. No LER is required 

because there are no corresponding 10 CFR 50.73 requirements. 

(3) Loss of Direct Communication Line to Police 

The licensee contacted the State Police via commercial telephone lines and reported to the 

NRC Operations Center that the direct telephone line to the State Police was inoperable for 

over 1 hour. The licensee notified the NRC Operations Center in a followup ENS call that 

the line was restored to operability. 

An ENS notification would be required if the loss of the direct telephone line(s) to various 

police, local, or State emergency or regulatory agencies is not compensated for by other 

readily available offsite communications systems. In this example, no ENS notification is 

required since commercial telephone lines to the State Police were available. No LER is 

required because there are no corresponding 10 CFR 50.73 requirements. 

3.2.14 Single Cause that Could Have Prevented Fulfillment of the Safety Functions of 

Trains or Channels in Different Systems 

§ 50.72 § 50.73(a)(2)(ix) 

There is no corresponding (A) Any event or condition that as a result of a 

requirement in § 50.72. single cause could have prevented the fulfillment of a 

safety function for two or more trains or channels in 

different systems that are needed to: 

(1) Shut down the reactor and maintain it in a safe 

shutdown condition; 

(2) Remove residual heat: 

(3) Control the release of radioactive material: or 

(4) Mitigate the consequences of an accident. 

(B) Events covered in paragraph (ix)(A) of this 

section may include cases of procedural error, 

equipment failure, and/or discovery of a design, 

analysis, fabrication, construction, and/or procedural 

inadequacy. However, licensees are not required to 

report an event pursuant to paragraph (ix)(A) of this 

section if the event results from: 

(1) A shared dependency among trains or channels 

that is a natural or expected consequence of the 

approved plant design: or 

(2) Normal and expected wear or degradation." 

An LER is required for an event that meets the conditions stated in the rule.

79 NUREG-1022, Rev. 2
Discussion

Subject to the two exclusions stated in the rule, this criterion captures those events where a 

single cause could have prevented the fulfillment of the safety function of multiple trains or 

channels, but the event: 

(1) Would not be captured by §§ 50.73(a)(2)(v) and 50.72(b)(3)(v) [event or condition that 

could have prevented fulfillment of the safety function of structures and systems 

needed to ...] because the affected trains or channels are in different systems; and 

(2) Would not be captured by § 50.73(a)(2)(vii) [common cause inoperability of 

independent trains or channels] because the affected trains or channels are either: 

(a) Not assumed to be independent in the plant's safety analysis; or 

(b) Not both considered to be inoperable. 

This criterion is closely related to §§ 50.73(a)(2)(v) and 50.72(b)(3)(v) [event or condition that 

could have prevented fulfillment of the safety function of structures and systems needed to: 

shut down the reactor and maintain it in a safe shutdown condition; remove residual heat; 

control the release of radioactive material; or mitigate the consequences of an accident]. 

Specifically: 

" The meaning of the term "could have prevented the fulfillment of the safety function" is 

essentially the same for this criterion as it is for §§ 50.73(a)(2)(v) and 50.72(b)(3)(v) [i.e., 

there was a reasonable expectation of preventing the fulfillment of the safety function(s) 

involved]. However, in contrast to §§ 50.73(a)(2)(v) and 50.72(b)(3)(v), reporting under this 

criterion applies to trains or channels in different systems. Thus, for this criterion, the 

safety function that is affected may be different in different trains or channels. 

" In contrast to §§ 50.73(a)(2)(v) and 50.72(b)(3)(v), reporting under this criterion applies only 

to a single cause. Also, in contrast to §§ 50.73(a)(2)(v) and 50.72(b)(3)(v), this criterion 

does not apply to an event that results from a shared dependency among trains or 

channels that is a natural or expected consequence of the approved plant design. For 

example, this criterion does not capture failure of a common electrical power supply that 

disables Train A of AFW and Train A of HPSI, because their shared dependency on the 

single power supply is a natural or expected consequence of the approved plant design. 

" Similar to §§ 50.73(a)(2)(v) and 50.72(b)(3)(v), this criterion does not capture events or 

conditions that result from normal and expected wear or degradation. For example, 

consider pump bearing wear that is within the normal and expected range. In the case of 

two pumps in different systems, this criterion categorically excludes normal and expected 

wear. In the case of two pumps in the same system, normal and expected wear should be 

adequately addressed by normal plant operating and maintenance practices and thus 

should not indicate a reasonable expectation of preventing fulfillment of the safety function 

of the system. 

The level of judgment for reporting an event or condition under this criterion is a reasonable

NUREG-1022, Rev. 2 80
expectation of preventing fulfillment of a safety function. In the discussions which follow, 

several different expressions such as "would have," "could have," "alone could have," and "reasonable doubt" are used to characterize this standard. In the staff's view, all of these 

should be judged on the basis of a reasonable expectation of preventing fulfillment of the 

safety function. 

The intent of this criterion is to capture those events where, as a result of a single cause, there 

would have been a failure of two or more trains or channels to properly complete their safety 

function, regardless of whether there was an actual demand. For example if, as a result of a 

single cause, a train of the high pressure safety injection system and a train of the auxiliary 

feedwater system failed, the event would be reportable even if there was no demand for the 

systems' safety functions. 

Examples of a single cause responsible for a reportable event may include cases of 

procedural error, equipment failure, and/or discovery of a design, analysis, fabrication, 

construction, and/or procedural inadequacy. They may also include such factors as high 

ambient temperatures, heat up from energization, inadequate preventive maintenance, oil 

contamination of air systems, incorrect lubrication, or use of non-qualified components. 

The event is reportable if, as a result of a single cause, there would have been a failure of two 

or more trains or channels to properly complete their safety function, regardless of whether the 

problem was discovered in both trains at the same time. 

Trains or channels for reportability purposes are defined as those trains or channels designed 

to provide protection against single failures. Many systems containing active components are 

designed as at least a two-train system. Each train in a two-train system can normally satisfy 

all the system functions. 

This criterion does not include those cases where trains or channels are removed from service 

as part of a planned evolution, in accordance with the plant's technical specifications. For 

example, if a licensee removes two trains from service to perform maintenance, and the 

Technical Specifications permit the resulting configuration, and the trains are returned to 

service within the time limits specified in the Technical Specifications, the action need not be 

reported under this paragraph. However, if, while the trains or channels are out of service, the 

licensee identifies a single cause that could have prevented the trains from performing their 

safety functions (e.g., the licensee finds a set of relays that is wired incorrectly), that condition 

must be reported. 

The definition of the systems included in the scope of this criterion is provided in the rule itself. 

It includes systems required by the technical specifications to be operable to perform one of 

the four functions specified in the rule. It is not determined by the phrases "safety-related," 

"important to safety," or "ESF." 

Trains or channels must operate long enough to complete their intended safety functions as 

defined in the safety analysis report. 

Generic Letter 91-18 provides guidance on determining whether a system is operable.

81 NUREG-1022, Rev. 2
The application of this reporting criterion and other reporting criteria involves the use of 

engineering judgment. In the case of this criterion, a technical judgment must be made as to 

whether a failure or operator action that did actually disable one train or channel, could have, 

but did not, disable another train or channel. If so, this would constitute an event that "could 

have prevented" the fulfillment of the safety function of multiple trains or channels, and, 

accordingly, must be reported. 

Reporting is required if one train or channel fails and, as a result of a single cause, there is 

reasonable doubt that another train or channel would remain operational until it completed its 

safety function or is repaired. For example, if a pump fails because of improper lubrication, 

and engineering judgment indicates that there is a reasonable expectation that another pump 

in a different system, which was also improperly lubricated, would have also failed before it 

completed its safety function, then the event is reportable under this criterion. 

Reportable conditions under this criterion include the following: 

"• an event or condition that disabled multiple trains because of a single cause 

" an event or condition where one train is disabled; in addition, (1) the underlying cause 

that disabled one train of a system could have failed another train and (2) there is 

reasonable expectation that the second train would not complete its safety function if it 

were called upon to do so 

"• an observed or identified event or condition that could have prevented fulfillment of the 

safety function of multiple trains or channels as a result of a single cause 

The following types of events or conditions generally are not reportable under this criterion: 

"* failures that affect inputs or services to systems that have no safety function (unless it 

could have prevented the performance of a safety function of an adjacent or interfacing 

system) 

"* a defective component that was delivered, but not installed 

" removal of trains or channels from service as part of a planned evolution for 

maintenance or surveillance testing when done in accordance with the plant's Technical 

Specifications (unless a condition is discovered that could have prevented multiple 

trains or channels from performing their safety functions) 

"* independent failure of a single component (unless it is indicative of a generic problem, 

which could have caused failure of multiple trains or channels) 

"• a procedure error that could have resulted in defeating the safety function of multiple 

trains or channels but was discovered before procedure approval 

"* a failure of a system used only to warn the operator where no credit is taken for it in 

any safety analysis and it does not directly control any of the four safety functions in 

the rule

NUREG-1022, Rev. 2 82
"* a single stuck control rod that would not have prevented the fulfillment of a reactor 

shutdown 

"* unrelated component failures in different trains or channels 

Minor operational events involving a specific component such as valve packing leaks, which 

could be considered a lack of control of radioactive material, should not be reported under this 

criterion. 

A design or analysis defect or deviation is reportable under this criterion if it could have 

prevented fulfillment of the safety function of multiple trains or channels. Reportability of a 

design or analysis defect or deviation under this criterion should be judged on the same basis 

that is used for other conditions, such as operator errors and equipment failures. That is, the 

condition is reportable if there is a reasonable expectation of preventing fulfillment of the 

safety function(s) of multiple trains or channels. Alternatively stated, the condition is reportable 

if there was reasonable doubt that the safety functions of multiple trains or channels would 

have been fulfilled if there were demands for them. 

Examples 

(1) Solenoid Operated Valve Deficiency 

During testing, two containment isolation valves failed to function as a result of improper air 

gaps in the solenoid operated valves that controlled the supply of instrument air to the 

containment isolation valves. 

The valves were powered from the same electrical division. Thus, § 50.73(a)(2)(vii) 

[common cause inoperability of independent trains or channels] would not apply. The two 

valves isolated fluid process lines in two different systems. Thus § 50.73(a)(2)(v) [condition 

that could have prevented fulfillment of the safety function of a structure or system] would 

apply only if engineering judgment indicates there was a reasonable expectation of 

preventing fulfillment of the safety function for redundant valves within the same system.1 6 

However, this criterion would certainly apply if a single cause (such as a design 

inadequacy) induced the improper air gaps, thus preventing fulfillment of the safety 

function of two trains or channels in different systems. 

(2) Degraded Valve Stems 

A motor operated valve in one train of a system was found with a crack 75 percent through 

the stem. Although the valve stem did not fail, engineering evaluation indicated that further 

cracking would occur which could have prevented fulfillment of its safety function. As a 

result, the train was not considered capable of performing its specified safety function. The 

valve stem was replaced with a new one. 

The root cause was determined to be environmentally assisted stress corrosion cracking 

16 Or, alternatively, there was reasonable doubt that the safety function would have been fulfilled if the 

affected trains had been called upon to perform them.

83 NUREG-1022, Rev. 2
which resulted from installation of an inadequate material some years earlier. The same 

inadequate material had been installed in a similar valve in a different system at the same 

time. The similar valve was exposed to similar environmental conditions as the first valve. 

The condition is reportable under this criterion if engineering judgment indicates that there 

was a reasonable expectation of preventing fulfillment of the safety function of both 

affected trains. This depends on details such as whether the second valve stem was also 

significantly degraded and, if not, whether any future degradation of the second valve stem 

would have been discovered and corrected, as a result of routine maintenance programs, 

before it could become problematic. 

(3) Overpressure due to Thermal Expansion 

It was determined that a number of liquid-filled and isolated containment penetration lines 

in multiple safety systems were not adequately designed to accommodate the internal 

pressure buildup that could occur because of thermal expansion caused by heatup after a 

design basis accident. The problem existed because the original design failed to consider 

this effect following a postulated accident. 

The condition is reportable under this criterion because there was a reasonable 

expectation of preventing fulfillment of the safety function of multiple trains or channels as 

a result of a single cause. 

(4) Cable Degradation 

One of three component cooling water pumps tripped due to a ground fault on a power 

cable leading to the pump. The likely cause was determined to be moisture permeation 

into the cable insulation over time in a section of cable that was exposed to water. 

The event is reportable under this criterion if engineering judgment indicates that there was 

a reasonable expectation of preventing fulfillment of the safety function of an additional 

train in a different system as a result of the same cause. For example, if cable testing 

indicates that another cable to safety related equipment was likely to fail as a result of the 

same cause the event is reportable. 

(5) Overstressed Valve Yokes 

It was determined that numerous motor operated valve yokes experienced over thrusting 

that exceeded design basis stress levels. The cause was lack of knowledge that resulted 

in inadequate design engineering at the time the designs were performed. 

Some of the motor operated valve yokes, in different systems, were being over stressed 

enough during routine operations that, although they were currently capable of performing 

their specified safety functions, the over stressing would, with the passage of time, render 

them incapable of performing those functions. The condition is reportable under this

NUREG-1022, Rev. 2 84
criterion if engineering judgment indicates there was a reasonable expectation of 

preventing fulfillment of the safety function of trains or channels in two or more different 

systems.1" 

(6) Heat Exchanger Fouling 

Periodic monitoring of heat exchanger performance indicated that two heat exchangers in 

two different systems required cleaning in order to ensure they would remain operable. 

The degree of fouling was within the range of normal expectations upon which the 

monitoring and maintenance procedures were based. 

The event is not reportable under this criterion because there was not a reasonable 

expectation of preventing the fulfillment of the safety function of the heat exchangers. 

(7) Pump Vibration 

Based on increasing vibration trends, identified by routine vibration monitoring, it was 

determined that a pump's bearings required replacement. Other pumps in different 

systems with similar designs and service histories experience similar bearing degradation. 

However, it is expected that the degradation will be detected and corrected before failure 

occurs. 

Such bearing degradation is not reportable under this criterion because it is normal and 

expected. 

3.3 Followup Notification 

This section addresses § 50.72(c), "Followup Notification." These notifications are in addition 

to making the required initial telephone notifications under § 50.72(a) or (b). Reporting under 

this paragraph is intended to provide the NRC with timely notification when an event becomes 

more serious or additional information or new analysis clarify an event. The paragraph also 

authorizes the NRC to maintain a continuous communications channel for acquiring necessary 

followup information. 

§ 50.72(c) § 50.73 

"Followup Notification. With respect to the There is no corresponding 

telephone notifications made under paragraphs (a) requirement in § 50.73. 

and (b) of this section, in addition to making the 

required initial notification, each licensee shall, during 

the course of the event: 

(1) Immediately report 

(i) any further degradation in the level of safety of 

the plant or other worsening plant conditions,

17 Or, alternatively, there was reasonable doubt that the safety function would have been fulfilled if the 

affected trains had been called upon to perform them.

85 NUREG-1022, Rev. 2
Discussion 

These criteria are intended to provide the NRC with timely notification when an event becomes 

more serious or additional information or new analyses clarify an event. They also permit the 

NRC to maintain a continuous communications channel because of the need for continuing 

followup information or because of telecommunications problems. 

With regard to the open, continuous communications channel, licensees have a responsibility 

to provide enough on-shift personnel, knowledgeable about plant operations and emergency 

plan implementation, to enable timely, accurate, and reliable reporting of operating events 

without interfering with plant operation as discussed in the Statement of Considerations for the 

rule and Information Notice 85-80, "Timely Declaration of an Emergency Class, Implementation 

of an Emergency Plan, and Emergency Notifications."

NUREG-1022, Rev. 2

including those that require the declaration of any of 

the Emergency Classes, if such a declaration has not 

been previously made, or 

(ii) any change from one Emergency Class to 

another, or 

(iii) a termination of the Emergency Class. 

(2) Immediately report 

(i) the results of ensuing evaluations or 

assessments of plant conditions, 

(ii) the effectiveness of response or protective 

measures taken, and 

(iii) information related to plant behavior that is not 

understood. 

(3) Maintain an open, continuous communication 

channel with the NRC Operations Center upon 

request by the NRC."

86
4 EMERGENCY NOTIFICATION SYSTEM REPORTING 

This section describes the ENS referenced in 10 CFR 50.72 and provides general and specific 

guidelines for ENS reporting. 

4.1 Emergency Notification System 

The NRC Operations Center is the nucleus of the ENS and has the capability to handle 

emergency communication needs. The NRC's response to both emergencies and non

emergencies is coordinated in this communication center. The key NRC emergency 

communications personnel, the emergency officer (EO), regional duty officer (RDO), and the 

headquarters operations officer (HOO), are trained to notify appropriate NRC personnel and to 

focus appropriate NRC management attention on any significant event. 

(1) ENS Telephones 

Each commercial nuclear power reactor facility has ENS telephones. These telephones 

are located in each licensee's control room, technical support center (TSC), and 

emergency operations facility (EOF). A separate ENS line is installed at EOFs which are 

not onsite. The ENS is part of the Federal Telecommuncations System (FlS). This FS 

ENS replaees the dedicated ENS ring down telephones used previctisly to provide 

reliable, communications pathway for event reporting ETS which is discussed further in 

Section 3.2.13 of this report. 

(2) Health Physics Network Telephones 

The HPN is designed to provide health physics and environmental information to the NRC 

Operations Center in the event of an ongoing emergency. These telephones are installed 

in each licensee's TSC and EOF and, like the ENS, they are part of the FFS-ETS. 

(3) Recording 

The NRC records all conversations with the NRC Operations Center. The tape is saved for 

a month in case there is a public or private inquiry. 

(4) Facsimile Transmission (Fax) 

Licensees occasionally fax an event notification into the NRC Operations Center on a 

commercial telephone line in conjunction with making an ENS notification. However, 

§ 50.72 requires that licensees notify the NRC Operations Center via the ENS; therefore, 

licensees also must make an ENS notification.

87 NUREG-1022, Rev. 2
4.2 General ENS Notification

4.2.1 Timeliness 

The required timing for ENS reporting is spelled out in §§ 50.72(a)(3), (b)(1), (b)(2), (b)(3), 

(c)(1), (c)(2), as "immediate" and "as soon as practical and in all cases within one (or four or 

eight) hour(s)" of the occurrence of an event (depending on its significance and the need for 

prompt NRC action). The intent is to require licensees to make and act on reportability 

decisions in a timely manner so that ENS notifications are made to the NRC as soon as 

practical, keeping in mind the safety of the plant. See Section 2.11 for further discussion of 

reporting timeliness. 

4.2.2 Voluntary Notifications 

Licensees may make voluntary or courtesy ENS notifications about events or conditions in 

which the NRC may be interested. The NRC responds to any voluntary notification of an event 

or condition as its safety significance warrants, regardless of the licensee's classification of the 

reporting requirement. If it is determined later that the event is reportable, the licensee can 

change the ENS notification to a required notification under the appropriate 10 CFR 50.72 

reporting criterion. 

4.2.3 ENS Notification Retraction 

If a licensee makes a 10 CFR 50.72 ENS notification and later determines that the event or 

condition was not reportable, the licensee should call the NRC Operations Center on the ENS 

telephone to retract the notification and explain the rationale for that decision. There is no set 

time limit for ENS telephone retractions. However, since most retractions occur following 

completion of engineering and/or management review, it is expected that retractions would 

occur shortly after such review. A retracted ENS report is retained in the ENS data base, 

along with the retraction. See section 2.8 for further discussion of retractions. 

4.2.4 ENS Event Notification Worksheet (NRC Form 361) 

The ENS Event Notification Worksheet (NRC Form 361) provides the usual order of questions 

and discussion for easier communication and its use often enables a licensee to prepare 

answers for a more clear and complete notification. A clear ENS notification helps the HOO to 

understand the safety significance of the event. Licensees may obtain an event number and 

notification time from the HOO when the ENS notification is made. If an LER is required, the 

licensee may include this information in the LER to provide a cross reference to the ENS 

notification, making the event easier to trace. 

Licensees should use proper names for systems and components, as well as their 

alphanumeric identifications during ENS notifications. Licensees should avoid using local 

jargon for plant components, areas, operations, and the like so that the HOO can quickly 

understand the situation and have fewer questions. In addition, others not familiar with the 

plant can more readily understand the situation.

NUREG-1022, Rev. 2 88
4.3 Typical ENS Reporting Issues

At the time of an ENS notification, the NRC must independently assess the status of the 

reactor to determine if it is in a safe condition and expected to remain so. The HOO needs to 

understand the safety significance of each event to brief NRC management or initiate an NRC 

response. The HOO will be primarily concerned about the safety significance of the event, the 

current condition of the plant, and the possible near-term effects the event could have on plant 

safety. The HOO will attempt to obtain as complete a description as is available at the time of 

the notification of the event or condition, its causes, and its effects. Depending upon the 

licensee's description of the event, the HOO may be concerned about other related issues. 

The questions that the licensees typically may be asked to discuss do not represent a 

requirement for reporting. These questions are of a nature to allow the HOO information to 

more fully understand the event and its safety significance and are not meant in any way to 

distract the licensee from more important issues. 

The licensee's first responsibility during a transient is to stabilize the plant and keep it safe. 

However, licensees should not delay declaring an emergency class when conditions warrant 

because delaying the declaration can defeat the appropriate response to an emergency. 

Because of the safety significance of a declared emergency, time is of the essence. The NRC 

needs to become aware of the situation as soon as practical to activate the NRC Operations 

Center and the appropriate NRC regional incident response center, as necessary, and to notify 

other Federal agencies. 

The effectiveness of the NRC response during an event depends largely on complete and 

accurate reporting from the licensee. During an emergency, the appropriate regional incident 

response center and the NRC Operations Center become focal points for NRC action. 

Licensee actions during an emergency are monitored by the NRC to ensure that appropriate 

action is being taken to protect the health and safety of the public. When required, the NRC 

supports the licensee with technical analysis and coordinates logistics support. The NRC 

keeps other Federal agencies informed of the status of an incident and provides information to 

the media. In addition, the NRC assesses and, if necessary, confirms the appropriateness of 

actions recommended by the licensee to local and State authorities. 

Information Notice 85-80, "Timely Declaration of an Emergency Class, Implementation of an 

Emergency Plan, and Emergency Notification," dated October 15, 1985, indicates that it is the 

licensee's responsibility to ensure that adequate personnel, knowledge about plant conditions 

and emergency plan implementing procedures, are available on shift to assist the shift 

supervisor to classify an emergency and activate the emergency plan, including making 

appropriate notifications, without interfering with plant operation. When 10 CFR 50.72 was 

published, the NRC made clear its intent in the Statements of Consideration that notifications 

on the ENS to the NRC Operations Center should be made by those knowledgeable of the 

event. If the description of any emergency is to be sufficiently accurate and timely to meet the 

intent of the NRC's regulations, the personnel responsible for notification must be properly 

trained and sufficiently knowledgeable of the event to report it correctly. The NRC did not 

intend that notifications made pursuant to 10 CFR 50.72 would be made by those who did not 

understand the event that they are reporting.

89 NUREG-1022, Rev. 2
ENS reportability evaluations should be concluded and the ENS notification made as soon as 

practical and in all cases within 1, 4 or 8 hours to meet 10 CFR 50.72. The Statement of 

Considerations noted that the 1-hour deadline is necessary if the NRC is to fulfill its 

responsibilities during and following the most serious events occurring at operating nuclear 

power plants without interfering with the operator's ability to deal with an accident or transient 

in the first few critical minutes (48 FR 39041, August 29, 1983).

NUREG-1022, Rev. 2 90
5 LICENSEE EVENT REPORTS

This section discusses the guidelines for preparing and submitting LERs. Section 5.1 

addresses administrative requirements and provides guidelines for submittal; Section 5.2 

addresses the requirements and guidelines for the LER content. Portions of the rule are 

quoted, followed by explanation, if necessary. A copy of the required LER form (NRC Form 

366), LER Text Continuation form (NRC Form 366A), and LER Failure Continuation form (NRC 

Form 366B), are shown at the end of this section. 

5.1 LER Reporting Guidelines 

This section addresses administrative requirements and provides guidelines for submittal. 

Topics addressed include submission of reports, forwarding letters, cancellation of LERs, 

report legibility, reporting exemptions, reports other than LERs that use LER forms, 

supplemental information, revised reports, and general instructions for completing LER forms. 

5.1.1 Submission of LERs 

§ 50.73(d) 

"Submission of reports. Licensee Event Reports must be prepared on Form NRC 366 

and submitted w"thn 30 days of dis.. very of a reportable event or situation to the U.S. 

Nuclear Regulatory Commission, as specified in § 50.4." 

An LER is to be submitted (mailed) within W3-60 days of the discovery date. If a -e-60-day 

period ends on a Saturday, Sunday, or holiday, reports submitted on the first working day 

following the end of the 3e-60 days are acceptable. If a licensee knows that a report will be 

late or needs an additional day or so to complete the report, the situation should be discussed 

with the appropriate NRC regional office. See Section 2.5 for further discussion of discovery 

date. 

5.1.2 LER Forwarding Letter and Cancellations 

The cover letter forwarding an LER to the NRC should be signed by a responsible official. 

There is no prescribed format for the letter. The date the letter is issued and the report date 

should be the same. Licensees are encouraged to include the NRC resident inspector and the 

Institute of Nuclear Power Operations (INPO) in their distribution. Multiple LERs can be 

forwarded by one forwarding letter.

91 NUREG-1022, Rev. 2
Cancellations of LERs submitted should be made by letter. The letter should state that the 

LER is being canceled (i.e., formally withdrawn). The bases for the cancellation should be 

explained so that the staff can understand and review the reasons supporting the 

determination. The notice of cancellation will be filed and stored with the LER and 

acknowledgement made in various automated data systems. The LER will be removed from 

the LER data base. 

5.1.3 Report Legibility

No further explanation is necessary. 

5.1.4 Voluntary LERs 

Indicate information-type LERS (i.e., voluntary LERs) by checking the "Other" block in Item 11 

of the LER form and type "Voluntary Report" in the space immediately below the block. Also 

give a sequential LER number to the voluntary report as noted in Section 5.2.4(5). Because 

not all requirements of § 50.73(b), "Contents," may pertain to some voluntary reports, 

licensees should develop the content of such reports to best present the information 

associated with the situation being reported. 

See Section 2.7 for additional discussion of voluntary LERs. 

5.1.5 Supplemental Information and Revised LERs

This provision authorizes the NRC staff to require the licensee to submit specific supplemental 

information. 

If an LER is incomplete at the time of original submittal or if it contains significant incorrect

NUREG-1022, Rev. 2

§ 50.73(e) 

"The reports and copies that licensees are required to submit to the Commission under the 

provisions of this section must be of sufficient quality to permit legible reproduction and 

micrographic processing."

§ 50.73(c) 

"The Commission may require the licensee to submit specific additional information beyond 

that required by paragraph (b) of this section if the Commission finds that supplemental 

material is necessary for complete understanding of any unusually complex or significant 

event. These requests for supplemental information will be made in writing and the 

licensee shall submit, as specified in § 50.4, the requested information as a supplement to 

the initial LER."

92
information of a technical nature, the licensee should use a revised report to provide the 

additional information or to correct technical errors discovered in the LER. Identify the revision 

to the original LER in the LER number as described in Section 5.2.7 Item (6). 

The revision should be complete and should not contain only supplementary or revised 

information to the previous LER because the revised LER will replace the previous report in 

the computer file. In addition, indicate in the text on the LER form the revised or 

supplementary information by placing a vertical line in the margin. 

If an LER mentions that an engineering study was being conducted, report the results of the 

study in a revised LER only if it would significantly change the reader's perception of the 

course, significance, implications, or consequences of the event or if it results in substantial 

changes in the corrective action planned by the licensee. 

Use revisions only to provide additional or corrected information about a reported event. Do 

not use a revision to report subsequent failures of the same or like component, except as 

permitted in 10 CFR 50.73. Some licensees have incorrectly used revisions to report new 

events that were discovered months after the original event because they were loosely related 

to the original event. These revisions had different event dates and discussed new, although 

similar, events. Report events of this type as new LERs and not as revisions to previous 

LERs. 

5.1.6 Special Reports 

There are a number of requirements in various sections of the technical specifications that 

require reporting of operating experience that is not covered by 10 CFR 50.73. If LER forms 

are used to submit special reports, check the "Other" block in item 11 of the form and type 

"Special Report" in the space immediately below the block. The provisions of § 50.73(b) may 

not be applicable or appropriate in a special report. Develop the content of the report to best 

present the information associated with the situation being reported. In addition, if the LER 

form is used to submit a special report, use a report number from the sequence used for LERs. 

If an event is reportable both under 10 CFR 50.73 and as a special report, check the block in 

Item 11 for the applicable section of 50.73 as well as the "Other" block for a special report. 

The content of the report should depend on the reportable situation. 

5.1.7 Appendix J Reports (Containment Leak Rate Test Reports) 

A licensee must perform containment integrated and local leak rate testing and report the 

results as required by Appendix J to 10 CFR Part 50. When the leak rate test identifies a 10 

CFR 50.73 reportable situation (see Section 3.2.4 or 3.3.1 of this report), submit an LER and 

include the results in an Appendix J report by reference, if desired. The LER should address 

only the reportable situation, not the entire leak rate test. 

5.1.8 10 CFR Part 21 Reports 

10 CFR Part 21, "Reporting of Defects and Noncompliance," as amended during 1991, 

encourages licensees of operating nuclear power plants to reduce duplicate evaluation and

93 NUREG-1022, Rev. 2
reporting effort by evaluating deviations in basic components under the 10 CFR 50.72, 50.73, 

and 73.71 reporting criteria. As indicated in 10 CFR 21.2(c) "For persons licensed to operate a 

nuclear power plant under Part 50 of this chapter, evaluation of potential defects and 

appropriate reporting of defects under §§ 50.72, 50.73. or § 73.71 of this chapter satisfies 

each person's evaluation, notification, and reporting obligation to report defects under this 

part ....." As discussed in the Statement of Considerations for 10 CFR 2118, the only case 

where a defect in a basic component of an operating reactor might be reportable under Part 

21, but not under §§ 50.72, 50.73, or 73.71 would involve Part(s) on the shelf. This type of 

defect, if it does not represent a condition reportable under §§ 50.72 or 50.73, might still 

represent a condition reportable under 10 CFR Part 21. 

For an LER, if the defect meets one of the criteria of 10 CFR 50.73, check the applicable 

paragraph in Item 11 of NRC Form 366 (LER Form). Licensees are also encouraged to check 

the "Other" block and indicate "Part 21" in the space immediately below if the defect in a basic 

component could create a substantial safety hazard. The wording in Item 16 ("Abstract") and 

Item 17 ("Text") should state that the report constitutes a Part 21 notification. If the defect is 

applicable to other facilities at a multi-unit site, a single LER may be used by indicating the 

other involved facilities in Item 8 on the LER Form. 

5.1.9 Section 73.71 Reports 

Submit events or conditions that are reportable under 10 CFR 73.71 using the LER forms with 

the appropriate blocks in Item 11 checked. If the report contains safeguards information as 

defined in 10 CFR 73.21, the LER forms may still be used, but should be appropriately marked 

in accordance with 10 CFR 73.21. Include safeguards and security information only in the 

narrative and not in the abstract. In addition, the text should clearly indicate the information 

that is safeguards or security information. Finally, the requirements of §73.21 (g) must be met 

when transmitting safeguards information. For additional guidelines on 10 CFR 73.71 

reporting, see Regulatory Guide 5.62, Revision 1, "Reporting of Safeguards Events," 

November 1987; NUREG-1304, "Reporting of Safeguards Events," February 1988; and 

Generic Letter 91-03, "Reporting of Safeguards Events," March 6, 1991. 

If the LER contains proprietary information, mark it appropriately in Item 17 (text) on of the LER 

form. Include proprietary information only in the narrative and not in the abstract. In addition, 

indicate clearly in the narrative the information that is proprietary. Finally, the requirements of 

§2.790(b) must be met when transmitting proprietary information. 

5.1.10 Availability of LER Forms 

The NRC will provide LER forms (i.e., NRC Forms 366, 366A, and 366B) free of charge. 

Copies may be obtained by writing to the NRC Records Management Branch, Office of the 

Chief Information Officer, US Nuclear Regulatory Commission, Washington, DC 20555. 

Electronic versions are also available. Licensees are encouraged to use these forms to assist 

the NRC's processing of the reports. 

18 56 FR 36081, July31, 1991.

NUREG-1022, Rev. 2 94
5.2 LER Content Requirements and Preparation Guidance

Licensees are required to prepare an LEl for these events Ic or nditions that meet one ol 

more of the criteria contained in § 56.79(a). Paragraph 50.73(b), "Contents," specifies the 

a nformation that an LEfl should contain with further explanation when appropriate. 

5.2.1 Optical Character Reader 

In 1900, the N•"- decided to use an opti.al chara-ter reader (O-fl) to read LER abstra"ts into 

NflC LER d-ata bases (IE Information Notice No. 86 08, "Liensee Event eport (LE-r) Format 

Modification," February 3, 1986). At that timne, licensees were asked to help reduce the 

nuimber of e!osinurd by the Oefl as a resuilt of incomnpatible print styles by using O)fl

compatible typography fr p.r.. L.s. T herefore, ,ean lmtations nave been p.ae.. on 

the uise of type styles and symbols for the abstract and text of the LIEfs. These limnitations are 

listed below. (See the Inform*ation~ Notice for details.) 

To help reduce the number of errors incurred by the Optical Character Reader (OCR) used to 

read LER contents into NRC data bases, the following practices are suggested. 

It is suggested that output be on typewriter or formed character (letter-quality or near letter

quality) printer (e.g., daisy wheel, laser, ink-jet). 

It is suggested that output have an uneven right margin (i.e., we suggest that you not right 

justify output).

It is suggested that text of the abstract be kept at least 1⁄2-inch inside the border on all sides of 

the area designated for the abstract on the LER form. Text running into the border can 

interfere with scanning the document. 

It is suggested that you do not use underscore, do not use bold print, do not use Italic print 

style, do not end any lines with a hyphen and do not use paragraph indents. Instead, print 

copy single space with a blank line between paragraphs. 

Limitations on the use of symbols in the textual areas: 

"* Spell out the word "degree." 

"* Use </= for "less than or equal to." 

"* Use >/= for "greater than or equal to." 

"* Use +/- for "plus or minus." 

"* Spell out all Greek letters. 

Do not use exponents. A number should either be expressed as a decimal, spelled out, or 

preferably designated in terms of "E" (E field format). For example, 4.2 x 10-6 could be 

expressed as 4.2E-6, 0.0000042, or 4.2 x 10(-6).

95 NUREG-1022, Rev. 2
Define all abbreviations and acronyms in both the text and the abstract and explain all 

component designators the first time they are used (e.g., the emergency service water pump 

1-SW-P-1 A) 

5.2.2 Narrative Description or Text (NRC Form 366A, Item 17) 

(1) General 

§ 50.73(b)(2)(i) 

The LER shall contain: "A clear, specific, narrative description of what occurred so that 

knowledgeable readers conversant with the design of commercial nuclear power plants, but 

not familiar with the details of a particular plant, can understand the complete event." 

There is no prescribed format for the LER text; write the narrative in a format that most clearly 

describes the event. After the narrative is written, however, review the appropriate sections of 

§ 50.73(b) to make sure that applicable subjects have been adequately addressed. It is 

helpful to use headings to improve readability. For example, some LERs employ major 

headings such as event description, safety consequences, corrective actions, and previous 

similar events and subheadings such as initial conditions, dates and times, event classification, 

systems status, event or condition causes, failure modes, method of discovery, component 

information, immediate corrective actions, and actions to prevent recurrence. 

Explain exactly what happened during the entire event or condition, including how systems, 

components, and operating personnel performed. Do not cover specific hardware problems in 

excessive detail. Describe unique characteristics of a plant as well as other characteristics that 

influenced the event (favorably or unfavorably). Avoid using plant-unique terms and 

abbreviations, or, as a minimum, clearly define them. The audience for LERs is large and 

does not necessarily know the details of each plant. 

Include the root causes, the plant status before the event, and the sequence of occurrences. 

Describe the event from the perspective of the operator (i.e., what the operator saw, did, 

perceived, understood, or misunderstood). Specific information that should be included, as 

appropriate, is described in paragraphs 50.73(b)(2)(ii), (b)(3), (b)(4), and (b)(5) of the rule and 

separately in the following sections. 

If several systems actuate during an event, describe all aspects of the complete event, 

including all actuations sequentially, and those aspects that by themselves would not be 

reportable. For example, if a single component failure (generally not reportable) occurs 

following a reactor scram (reportable), describe the component failure in the narrative of the 

LER for the reactor scram. It is necessary to discuss the performance and status of equipment 

important for defining and understanding what happened and for determining the potential 

implications of the event. 

Paraphrase pertinent sections of the latest submitted safety analysis report (SAR) rather than 

referencing them because not all organizations or individuals have access to SARs. Extensive

NUREG-1022, Rev. 2 96
cross-referencing would be excessively time consuming considering the large number of LERs 

and large number of reviewers that read each LER. Ensure that each applicable component's 

safety-significant effect on the event or condition is clearly and completely described. 

Do not use statements such as "this event is not significant with respect to the health and 

safety of the public" without explaining the basis for the conclusion. 

§ 50.73(b)(2)(ii)(A) 

The narrative description must include: "Plant operating conditions before the event." 

Describe the plant operating conditions such as power level or, if not at power, describe mode, 

temperature, and pressure that existed before the event.

If there were no structures, systems, or components that were inoperable at the start of the 

event and contributed to the event, so state. Otherwise, identify SSCs that were inoperable 

and contributed to the initiation or limited the mitigation of the event. This should include 

alternative mitigating SSCs that are a part of normal or emergency operating procedures that 

were or could have been used to mitigate, reduce the consequences of, or limit the safety 

implications of the event. Include the impact of support systems on mitigating systems that 

could have been used.

For a transient or system actuation event, the event date and time are the date and time the 

event actually occurred. If the event is a discovered condition for which the occurrence date is 

not known, the event date should be specified as the discovery date. However, a discussion 

of the best estimate of the event date and its basis should be provided in the narrative. For 

example, if a design deficiency was identified on March 27, 1997 that involved a component 

installed during refueling in the spring of 1986, and only the discovery date is known with 

certainty, the event date should be specified as the discovery date. A discussion should be 

provided that describes, based on the best information available, the most likely time that the 

design flaw was introduced into the component (e.g., by manufacturer or by plant engineering

NUREG-1022, Rev. 2

§ 50.73(b)(2)(ii)(B) 

The narrative description must include: "Status of structures, components, or systems that 

were inoperable at the start of the event and that contributed to the event."

§ 50.73(b)(2)(ii)(C) 

The narrative description must include: "Dates and approximate times of occurrences."

97
prior to procurement). The length of time that the component was in service should also be 

provided (i.e., when it was installed). 

Discuss both the discovery date and the event date if they differ. If an LER is not submitted 

within 30-60 days from the event date, explain the relationship between the event date, 

discovery date, and report date in the narrative. See Section 2.5 for further discussion of 

discovery date. 

Give dates and approximate times for all major occurrences discussed in the LER (e.g., 

discoveries; immediate corrective actions; systems, components, or trains declared inoperable 

or operable; reactor trip; actuation and termination of equipment operation; and stable 

conditions achieved). In particular, for standby pumps and emergency generators, indicate the 

length of time of operation and any intermittent periods of shutdown or inoperability during the 

event. Include an estimate of the time and date of failure of systems, components, or trains if 

different from the time and date of discovery. A chronology may be used to clarify the timing 

of personnel and equipment actions. 

For equipment that was inoperable at the start of the event, provide an estimate of the time the 

equipment became inoperable and the last time the equipment was demonstrated to be 

capable of performing its safety function. The licensee should provide the basis for this 

conclusion (e.g., a test was successfully run or the equipment was operating). For equipment 

that failed, provide the failure time and the last time the equipment was demonstrated to be 

capable of performing its safety function. The licensee should provide the basis for this 

conclusion (e.g., a test was performed or the equipment was operating). 

Components such as valves and snubbers may be tested over a period of several weeks. 

During this period, a number of inoperable similar components may be discovered.' 9 In such 

cases, similar failures that are reportable and that are discovered during a single test program 

within the 30-60 days of discovery of the first failure may be reported as one LER. For similar 

failures that are reportable under Section 50.73 criteria and that are discovered during a single 

test program or activity, report all failures that occurred within the first 30-60 days of discovery 

of the first failure on one LER. However, the 8e-60-day clock starts when the first reportable 

event is discovered. State in the LER text (and code the information in Items 14 and 15) that a 

supplement to the LER will be submitted when the test is completed. Submit a revision to the 

original LER when the test is completed. Include all the failures, including those reported in 

the original LER, in the revised LER (i.e., the revised LER should stand alone). 

(2) Failures and Errors 

§ 50.73(b)(2)(ii)(D) 

The narrative description must include: "The cause of each component or system failure or 

personnel error, if known." 

19 Note that inoperable similar components might indicate common cause failures of independent trains or 

channels, which are reportable under § 50.73(a)(2)(vii); see Section 3.3.4 for further discussion.

NUREG-1022, Rev. 2 98
Include the root cause(s) identified for each component or system failure (or fault) or personnel 

error. Contributing factors may be discussed as appropriate. For example, a valve stem 

breaking could have been caused by a limit switch that had been improperly adjusted during 

maintenance; in this case, the root cause might be determined to be personnel error and 

additional discussion could focus on the limit switch adjustment. If the personnel error is 

determined to have been caused by deficient procedures or inadequate personnel training, this 

should be explained. 

If the cause of a failure cannot be readily determined and the investigation is continuing, the 

licensee should indicate what additional investigation is planned. A supplemental LER should 

be submitted following the additional investigation if substantial information is identified that 

would significantly change a reader's perception of the course or consequences of the event, 

or if there are substantial changes in the corrective actions planned by the licensee. 

§ 50.73(b)(2)(ii)(E) 

The narrative description must include: "The failure mode, mechanism, and effect of each 

failed component, if known." 

Include the failure mode, mechanism (immediate cause), and effect of each failed component 

in the narrative. The effect of the failure on safety systems and functions should be fully 

described. Identify the specific piece part that failed and the specific trains and systems 

rendered inoperable or degraded. Identify all dependent systems rendered inoperable or 

degraded. Indicate whether redundant trains were operable and available. 

If the equipment is degraded, but not failed, the licensee should describe the degradation and 

its effects and indicate the basis for the conclusion that the equipment would still perform its 

intended function.

NUREG-1022, Rev. 2

§ 50.73(b)(2)(ii)(F) 

The narrative description must include: "The Energy Industry Identification System 

component function identifier and system name of each component or system referred to in 

the LER. 

(1) The Energy Industry Identification System is defined in: IEEE Std 803-1983 (May 

16, 1983) Recommended Practice for Unique Identification in Power 

Plants and Related Facilities--Principles and Definitions. 

(2) IEEE Std 803-1983 has been approved for incorporation by reference by the 

Director of the Federal Register. 

(3) A notice of any changes made to the material incorporated by reference will be 

published in the Federal Register. Copies may be obtained from the Institute of Electrical 

and Electronics Engineers, 345 East 47th Street, New York, NY 10017. IEEE Std 

803-1983 is available for inspection at the NRC's Technical Library, which is located in the

99
Two White Flint North Building, 11545 Rockville Pike, Rockville, Maryland; and at the Office 

of the Federal Register, 1100 L Street, NW, Washington, DC." 

The system name may be either the full name (e.g., reactor coolant system) or the two-letter 

system code (such as AB for the reactor coolant system). However, when the name is long 

(e.g., low-pressure coolant injection system), the system code (e.g., BO) should be used. If 

the full names are used, The Energy Industry Identification System (EIIS) component function 

identifier and/or system identifier (i.e., the two letter code) should be included in parentheses 

following the first reference to a component or system in the narrative. The component 

function identifiers and system identifiers need not be repeated with each subsequent 

reference to the same component or system. 

If a component within the scope of the Equipment Performance and Information Exchange 

(EPIX) System is involved, the system and train designation should be consistent with the EIIS 

used in EPIX.

No further explanation is necessary.

No further explanation is necessary.

NUREG-1022, Rev. 2

§ 50.73(b)(2)(ii)(G) 

The narrative description must include the following specific information as appropriate for 

the particular event: "For failures of components with multiple functions, include a list of 

systems or secondary functions that were also affected."

§ 50.73(b)(2)(ii)(H) 

The narrative description must include: "For failure that rendered a train of a safety system 

inoperable, an estimate of the elapsed time from the discovery of the failure until the train 

was returned to service."

§ 50.73(b)(2)(ii)(I) 

The narrative description must include: "The method of discovery of each component or 

system failure or procedural error."

100
Explain how each component failure, system failure, personnel error, or procedural deficiency 

was discovered. Examples include reviewing surveillance procedures or results of surveillance 

tests, pre-startup valve lineup check, performing quarterly maintenance, plant walkdown, etc.

S...uan pe'ormance often influences the outcome of nuclear power plant events. 1 luypan 

error is known to contribute to more than half of the LEfls. The LEfl rule identifies the types of

reao eIven•sl and problems t.•at are beiJlle. to be sig nihi.ant •l and seri• to the Illl5 in its 

effort to identify and resolve threats to public safety. it is designed to provide the information * *%,C%%,CIS 7 ~I*t** ~ 4.~)SU Ai.t 0. SJ.% SA~ioJmI.C Cl q 's%^PA Cj p1q01. *P LI'I ..AU.) 4CMAl 1.tJaLUpFIq I Al R6I

Ull.pJla;.U at cpetip l l. l .• ln..IU.lll Il Iritim n Ierformanc e.

Generally, the criteria of Section 50.73(b)(2)(i) require a clear, specific narrative so that 

knowledgeable readers can understand the complete event. Further, for each human 

performance related root cause, the criteria of Section 50.73(b)(2)(ii)(J) require a description of 

(1) operator actions that aff.eeted the eourse of the event and (2) for each personnel ereror, 

additional specffic information as detailed in the rule. the cause(s) and circumstances. In order 

to support an understanding of human performance issues related to the event, the narrative 

should address the factors discussed below to the extent they apply.

I or example, it an operator error that a•ltetedl thle ecurse of the event was due to a procedur-al problem, indicate the natutre of the procedural problem such asmssn rocedure, procedure 

inadequate du. e to technical deficiency, ete. 

Personnel errors and human perforImance related issu.es may be in the areas of procedures, 

training, eonuiain human engieri0 -anagement, m and stipervision. For example, in 

the area of procedures, errors might be due to msin proedres, procedures which are9 IlC 4 1 : A.~L C J :4 : ~ 1 .I 0IICA i 1 1.1I il IU.L- I A C.4 ý L._ 0 1-i LY &j.I L_ e~V 6. :U AJ~ "II CL1II I"V

NUREG-1022, Rev. 2

§ 50.73(b)(2)(ii)(J) 

The narrative description must include: "For each human performance related root cause, 

the licensee shall discuss the cause(s) and circumstances."

(7Y) wperater aetions tmat attectea tne eaturse ot me event, inewiudng Operator errors, 

procedurai defilgeneies, or both, that •otribiUted to the evet. /4P) PR- 0-h. novennnL .. .I... -Pr ~ Aq-1 -I . ... e all 4.......

I Vfl I '/

LA.JI/ I1.IllLlIJI I, Ia111.il~ ~ L n I• l;;:ll/. U3l VVI Iil.,l I O~ I IO Ol ll•.Ir.JUI LJ,/l; IUl Il.LJI III ll.J IQI~IUI • LU I ~LUlI~.•:ll/.; I L U | I 

true natuire of the event) or a procedural error; 

(H)~ Whether the error was contrary to an approved proeedure, was a direct resuilt of 

an error in an approved procedure, or was associated with an ativity or task that was not 

covered by an approved procedure. 

SAmy unusual eharaeteristies of the work location (e.g., heat, noise) that ddirectl:y 

onributed to the errr and 

qav) The tvne of ijersonnel imvolved (i.e. eontraeter nersonnel utilitv ien

,IJ l(IU~ JI , U l fllILy 11Jl IvI' l I tjpUjJ CI aLuI ,

Ill LI ll. U.41 S.flA 1St LU 1.411 1131 , 1SI I *JI US BILl>)' 151.. LI RCA CAUSLUIL lii CA ICASILJI 14. LCd pi 'dv IC.414. LI CARl I*I I, I ICAVIS

* 1 U &

-- . .• \ . . . . . .7.. . . . .; . . . . . . . 

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I . - -. / r . . • - - Jr'- . . . . .. . . .. . . .

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+ • + LI I I

(• L I lI,.Iw iL I IrL •. •. .. 1Vr• )

II~~~ IIle;..UGA ~~ I. II Lim; Il~ I.I. l(;L"l 1..;~ I kjVUo U I- .lIU;l & lVO, VI tII.4 Cll VU; II"1 U V"llI

.l I .tj,. , •/ ,Jwllll•ý l l ,• I/ ll • Il ,lýl,"Jl (]IU I; 1• •l• V li• 1.(ZlII )lIIJ , I•¥ I•

101
provided inadequate traiig, rasthe result of training (sueh as simulator training -of 

on the-job training) that, wosntpoide an enviromnment eomparable to that in the plant. 

"ommunications error may be due to inadequate, untimely, misunderstood, or missing 

comuiction or due t-o the qujality of the eomnmunication equipment. I lumanm engineering-ý 

iss1Tes ncluede these related to the inteoate or laek thereof between the human and the 

rmachine (such as size, shape, location, function or content of displays, controls, equipmenmt or 

labels) as well as environmental issues suceh as lighting, temperature, noise, radiation and 

work area layout. Management errors might be due to management expeetations, corrective 

actions, root eatse detoerminations, or audits which are inadequate, untimely or missing. in the 

area of suiin, her rors may be the result of a :aek of suprovd trinaidequate suhv inovid 

job staffingd, overteie, sheduling and planning, work practices (such as briefings, logs, work 

packages, teamn work, decision making, and housekeeping) or because of inadequate 

verification, awareness or seil-checking. 

M The cause(s). including any relation to the areas of: 

LCm Procedures, where errors may be due to missing procedures, procedures which are 

inadequate due to technical or human factors deficiencies, or which have not been 

maintained current. 

(j} Training, where errors may be the result of a failure to provide training, having provided 

inadequate training, or as the result of training (such as simulator training or on-the-iob 

training) that does not provide an environment comp~arable to that in the p~lant. 

(c) Communications. where errors may be due to inadequate, untimely, misunderstood, or 

missing communication or be due to the cluality of the communication equipment. 

fd Human-system interface, such as size, shape, location, function or content of displays, 

controls, equipment or labels, as well as environmental issues such as lighting, 

temperature, noise, radiation and work area layout. 

S(e) Supervision and oversight, where errors may be the result of inadequate command and 

control, work control, corrective actions, self-evaluation, staffing, task allocation, 

overtime, or schedule design. 

(f) Fitness for duty, where errors may be due to the influence of any substance legal or 

illegal, or mental or physical impairment, e.g., mental stress, fatigue or illness. 

(g) Work practices such as briefings, logs, work packages, team work, decision making, 

housekeeping, verification, awareness or attention. 

(2 The circumstances, including: 

(a) The personnel involved, whether they are contractor or utility personnel, whether or not 

they are licensed, and the department for which they work. 

(b_ The work activity being performed and whether or not there were any time or situational 

pressures present.

NUREG-1022, Rev. 2 102
The manufacturer and model number (or other identification, such as type, size, or 

manufacture date) also should be given for each component found failed during the course of 

the event. An example of other identification could be (for a pipe rupture) size, schedule, or 

material composition. 

(4) Safety System Responses

The LER should include a discussion of each specific system that actuated or failed to actuate. 

Do not limit the discussion to ESFs. Indicate whether or not the equipment operated 

successfully. For some systems such as HPCI, RCIC, RHR, and AFW, the type of actuation 

may not be obvious. In those cases indicate the specific equipment that actuated or should 

have actuated, by train, compatible with EPIX train definitions (e.g., AFW Train B). Indicate 

the mode of operation such as iniecting into the reactor vessel, recirculation, pressure control,

and any subseauent mode of operation durina the event.

5.2.3 Assessment of Safety Consequences

Give a summary assessment of the actual and potential safety consequences and implications 

of the event, including the basis for submitting the report. Evaluate the event to the extent

NUREG-1022, Rev. 2

§ 50.73(b)(2)(ii)(L) 

The narrative description must include: "The manufacturer and model number (or other 

identification) of each component that failed during the event."

§ 50.73(b)(2)(ii)(K) 

The narrative description must include: "Automatically and manually initiated safety system 

responses."

§ 50.73(b)(3) 

The LER shall contain: "An assessment of the safety consequences and implications of 

the event. This assessment must include: 

(i) The availability of systems or components that could have performed the same 

function as the components and systems that failed during the event, and 

(ii) For events that occurred when the reactor was shutdown, the availability of systems 

or components that are needed to shutdown the reactor and maintain safe shutdown 

conditions, remove residual heat, control the release of radioactive material, or mitigate the 

conseauences of an accident.

103
necessary to fully assess the safety consequences and safety margins associated with the 

event. 

Include an assessment of the event under alternative conditions if the incident would have 

been more severe (e.g., the plant would have been in a condition not analyzed in its latest 

SAR) under reasonable and credible alternative conditions, such as a different operating 

mode. For example, if an event occurred while the plant was at low power and the same event 

could have occurred at full power, which would have resulted in considerably more serious 

consequences, this alternative condition should be assessed and the consequences reported. 

Reasonable and credible alternative conditions may include normal plant operating conditions, 

potential accident conditions, or additional component failures, depending on the event. 

Normal alternative operating conditions and off-normal conditions expected to occur during the 

life of the plant should be considered. The intent of this section is to obtain the result of the 

considerations that are typical in the conduct of routine operations, such as event reviews, not 

to require extraordinary studies. 

For events that occurred when the reactor was shutdown, discuss the availability of systems or 

components that are needed to shutdown the reactor and maintain safe shutdown conditions, 

remove residual heat, control the release of radioactive material, or mitigate the consequences 

of an accident. 

5.2.4 Corrective Actions 

§ 50.73(b)(4) 

The LER shall contain: "A description of any corrective actions planned as a result of the 

event, including those to reduce the probability of similar events occurring in the future." 

Include whether the corrective action was or is planned to be implemented. Discuss repair or 

replacement actions as well as actions that will reduce the probability of a similar event 

occurring in the future. For example, "the pump was repaired and a discussion of the event 

was included in the training lectures." Another example, "although no modification to the 

instrument was deemed necessary, a caution note was placed in the calibration procedure for 

the instrument before the step in which the event was initiated." 

In addition to a description of any corrective actions planned as a result of the event, describe 

corrective actions on similar or related components that were done, or are planned, as a direct 

result of the event. For example, if pump 1 failed during an event and required corrective 

maintenance and that same maintenance also was done on pump 2, so state. 

If a study was conducted, and results are not available within the 30-60-day period, report the 

results of the study in a revised LER if they result in substantial changes in the corrective 

action planned. (See Section 5.1.6 for further discussion of submitting revised LERs.)

NUREG-1022, Rev. 2 104
5.2.5 Previous Occurrences

The term "previous occurrences" should include previous events or conditions that involved the 

same underlying concern or reason as this event, such as the same root cause, failure, or 

sequence of events. For infrequent events such as fires, a rather broad interpretation should 

be used (e.g., all fires and, certainly, all fires in the same building should be considered 

previous occurrences). For more frequent events such as ESF actuations, a narrower 

definition may be used (e.g., only those scrams with the same root cause). The intent of the 

rule is to identify generic or recurring problems. 

The licensee should use engineering judgment to decide how far back in time to go to present 

a reasonably complete picture of the current problem. The intent is to be able to see a pattern 

in recurring events, rather than to get a complete 10- or 20-year history of the system. If the 

event was a high-frequency type of event, 2 years back may be more than sufficient. 

Include the LER number(s), if any, of previous similar events. Previous similar events are not 

necessarily limited to events reported in LERs. If no previous similar events are known, so 

state. If any earlier events, in retrospect, were significant in relation to the subject event, 

discuss why prior corrective action did not prevent recurrence. 

5.2.6 Abstract (NRC Form 366, Item 16) 

§ 50.73(b)(1) 

The LER shall contain: "A brief abstract describing the major occurrences during the 

event, including all component or system failures that contributed to the event and 

significant corrective action taken or planned to prevent recurrence." 

Provide a brief abstract describing the major occurrences during the event, including all actual 

component or system failures that contributed to the event, all relevant operator errors or 

violations of procedures, the root cause(s) of the major occurrence(s), and the corrective 

action taken or planned for each root cause. If space does not permit describing failures, at 

least indicate whether or not failures occurred. Limit the abstract to 1400 characters (including 

spaces), which is approximately 15 lines of single-spaced typewritten text. Do not use EIIS 

component function identifiers or the two-letter codes for system names in the abstract. 

The abstract is generally included in the LER data base to give users a brief description of the

NUREG-1022, Rev. 2

§ 50.73(b)(5) 

The LER shall contain: "Reference to any previous similar events at the same plant that 

are known to the licensee."

105
event to identify events of interest. Therefore, if space permits, provide the numbers of other 

LERs that reference similar events in the abstract. 

As noted in Section 5.1.10, do not include safeQuards, security, or proprietary information in 

the abstract. 

5.2.7 Other Fields on the LER Form 

(1) Facility Name (NRC Form 366, Item 1) 

Enter the name of the facility (e.g., Indian Point, Unit 1) at which the event occurred. If the 

event involved more than one unit at a station, enter the name of the nuclear facility with the 

lowest nuclear unit number (e.g., Three Mile Island, Unit 1). 

(2) Docket Number (NRC Form 366, Item 2) 

Enter the docket number (in 8-digit format) assigned to the unit. For example, the docket 

number for Yankee-Rowe is 05000029. Note the use of zeros in this example. 

(3) Page Number (NRC Form 366, Item 3) 

Enter the total number of pages included (including figures and tables that are attached to Item 

17 Text) in the LER package. For continuation sheets, number the pages consecutively 

beginning with page 2. The LER form, including the abstract and other data is pre-numbered 

on the form as page 1 of . 

(4) Title (NRC Form 366, Item 4) 

The title should include a concise description of the principal problem or issue associated with 

the event, the root cause, the result (why the event was required to be reported), and the link 

between them, if possible. It is often easier to form the title after writing the assessment of the 

event because the information is clearly at hand. 

"Licensee Event Report" should not be used as a title. The title "Reactor Trip" is considered 

inadequate, because the root cause and the link between the root cause and the result are 

missing. The title "Personnel Error Causes Reactor Trip" is considered inadequate because of 

the innumerable ways in which a person could cause a reactor trip. "Technician Inadvertently 

Injected Signal Resulting in a Reactor Trip" would be a better title. 

(5) Event Date (NRC Form 366, Item 5) 

Enter the date on which the event occurred in the eight spaces provided. There are two 

spaces for the month, two for the day, and four for the year, in that order. Use leading zeros in 

the first and third spaces when appropriate. For example, June 1, 1987, would be properly 

entered as 06011987. 

If the date on which the event occurred cannot be clearly defined, use the discovery date. See 

Section 2.11 of this report for further discussion of discovery date.

NUREG-1022, Rev. 2 106
(6) Report Number (NRC Form 366, Item 6)

The LER number consists of three parts: (a) the four digits of the event year (based on event 

date), (b) the sequential report number, and (c) a revision number. The numbering system is 

shown in the diagram below; the event occurred in the year 1991, it was the 45th event of that 

year, and the submittal was the 1st revision to the original LER for that event. 

Event Sequential Revision 

Year Report Number Number 

1991 045 - 01 

Event Year: Enter the four digits. The event year should be based on the event date (Item 4). 

Sequential Report Number: As each reportable event is reported for a unit during the year, it is 

assigned a sequential number. For example, for the 15th and 33rd events to be reported in a 

given year at a given unit, enter 015 and 033, respectively, in the spaces provided. Follow the 

guidelines below to ensure consistency in the sequential numbering of reports. 

"* Each unit should have its own set of sequential report numbers. Units at multi-unit sites 

should not share a set of sequential report numbers. 

"* The sequential number should begin with 001 for the first event that occurred in each 

calendar year, using leading zeros for sequential numbers less than 100. 

"* For an event common to all units of a multi-unit site, assign the sequential number to the 

lowest numbered nuclear unit. 

If a sequential number was assigned to an event, and it was subsequently determined that 

the event was not reportable, a "hole" in the series of LER numbers would result. The NRC 

would prefer that licensees reuse a sequential number rather than leave holes in the 

sequence. A sequential LER number may be reused even if the event date was later than 

subsequent reports. 

If the licensee chooses not to reuse the number, write a brief letter to the NRC noting that 

"LER number xxx for docket oo5o0oXXX will not be used." 

Revision Number: The revision number of the original LER submitted is 00. The revision 

number for the first revision submitted should be 01. Subsequent revisions should be 

numbered sequentially (i.e., 02, 03, 04). 

(7) Report Date (NRC Form 366, Item 7) 

Enter the date the LER is submitted to the NRC in the eight spaces provided, as described in 

Section 5.2.4(4) above.

107 NUREG-1022, Rev. 2
(8) Other Facilities (NRC Form 366, Item 8)

When a situation is discovered at one unit of a facility that applies to more than the one unit, 

submit a single LER. LER form items 1, 2, 6, 9, and 10 should refer to the unit primarily 

affected, or, if both units were affected approximately equally, to the lowest numbered nuclear 

unit. 

The intent of the requirement is to name the facility in which the primary event occurred, 

whether or not that facility is the lowest numbered of the facilities involved. The automatic use 

of the lowest number should only apply to cases where both units are affected approximately 

equally. Item 8 only should indicate the other unit(s) affected. The abstract and the text 

should describe how the event affected all units. 

Enter the facility name and unit number and docket number (see Sections 5.2.4(1) and 

5.2.4(2) for format) of any other units at that site that were directly affected by the event (e.g., 

the event included shared components, the LER described a tornado that threatened both 

units of a two-unit plant). 

(9) Operating Mode (NRC Form 366, Item 9) 

Enter the operating mode of the unit at the time of the event as defined in the plant's technical 

specifications in the single space provided. For plants that have operating modes such as hot 

shutdown, cold shutdown, and operating, but do not have numerical operating modes (e.g., 

Mode 5), place the letter N in Item 9 and describe the operating mode in the text. 

(10) Power Level (NRC Form 366, Item 10) 

Enter the percent of licensed thermal power at which the reactor was operating when the event 

occurred. For shutdown conditions, enter 000. For all other operating conditions, enter the 

correct numerical value (estimate power level if it is not known precisely), using leading zeros 

as appropriate (e.g., 009 for 9-percent power). Significant deviations in the operating power in 

the balance of plant should be clarified in the text. 

(11) Reporting Reguirements (NRC Form 366, Item 11) 

Check one or more blocks according to the reporting requirements that apply to the event. A 

single event can meet more than one reporting criterion. For example: if as a result of 

sabotage, reportable under §73.71 (b), a safety system failed to function, reportable under 

§ 50.73(a)(2)(v), and the net result was a release of radioactive material in a restricted area 

that exceeded the applicable license limit, reportable under §20.2203(a)(3)(i), prepare a single 

LER and check the three boxes for paragraphs 73.71(b), 50.73(a)(2)(v), and 20.2203(a)(3)(i). 

In addition, an event can be reportable as an LER even if it does not meet any of the criteria of 

10 CFR 50.73. For example, a case of attempted sabotage (§73.71(b)) that does not result in 

any consequences that meet the criteria in 50.73 can be reported using the "Other" block. Use 

the "Other" block if a reporting requirement other than those specified in item 11 was met. 

Specifically describe this other reporting requirement in the space provided below the "Other" 

block and in the abstract and text.

NUREG-1022, Rev. 2 108
(12) Licensee Contact (NRC Form 366, Item 12)

Enter the name, position title, and work telephone number (including area code) of a person 

who can provide additional information and clarification for the event described in the LER. 

(13) Component Failures (NRC Form 366, Item 13) 

Enter the appropriate data for each component failure described in the event. 

A failure is defined as the termination of the ability of a component to perform its required 

function. Unannounced failures are not detected until the next test; announced failures are 

detected by any number of methods at the instant of occurrence. 

If multiple components of the same type failed and all of the information required in Item 13 

(i.e., cause, system, component, etc.) was the same for each component, then only a single 

entry is required in Item 13. Clearly define the number of components that failed in the 

abstract and text. 

The component information elements of this item are discussed below. 

Cause: Enter the cause code as shown below. If more than one cause code is applicable, 

enter the cause code that most closely describes the root cause of the failure. 

Cause 

Code Classification and Definition 

A Personnel Error is assigned to failures attributed to human errors. Classify errors made 

because written procedures were not followed or because personnel did not perform in 

accordance with accepted or approved practice as personnel errors. Do not include 

errors made as a result of following incorrect written procedures in this classification. 

B Design, Manufacturing, Construction/Installation is assigned to failures reasonably 

attributed to design, manufacture, construction, or installation of a system, component, 

or structure. For example, include failures that were traced to defective materials or 

components otherwise unable to meet the specified functional requirements or 

performance specifications in this classification. 

C External Cause is assigned to failures attributed to natural phenomena. A typical 

example would be a failure resulting from a lightning strike, tornado, or flood. Also 

assign this classification to man-made external causes that originate off site (e.g., an 

industrial accident at a nearby industrial facility).

NUREG-1022, Rev. 2

§ 50.73(b)(6) 

The LER shall contain: "The name and telephone number of a person within the licensee's 

organization who is knowledgeable about the event and can provide additional information 

concerning the event and the plant's characteristics."

109
D Defective Procedure is assigned to failures caused by inadequate or incomplete written 

procedures or instructions. 

E Management/Quality Assurance Deficiency is assigned to failures caused by 

inadequate management oversight or management systems (e.g., major breakdowns in 

the licensee's administrative controls, preventive maintenance program, surveillance 

program, or quality assurance controls, inadequate root cause determination, 

inadequate corrective action). 

X Other is assigned to failures for which the proximate cause cannot be identified or 

which cannot be assigned to one of the other classifications. 

System: Enter the two-letter system code from Institute of Electrical and Electronics 

Engineers (IEEE) Standard 805-1984, "IEEE Recommended Practice for System 

Identification in Nuclear Power Plants and Related Facilities," March 27, 1984. Copies 

may be obtained from the Institute of Electrical and Electronics Engineers, 345 East 

47th Street, New York, NY 10017. 

Component: Enter the applicable component code from I EEE Standard 803A-1 983, 

"IEEE Recommended Practice for Unique Identification in Power Plants and Related 

Facilities - Component Function Identifiers." 

Component Manufacturer: Enter the four character alphanumeric reference code. If 

the manufacturer is one used in EPIX, use the manufacturer name as it appears in 

EPIX. 

Reportable to EPIX: Enter a "Y" if the failure is reportable to EPIX and an "N" if it is not 

reportable. 

Include in the LER text and in item 13 of the LER Form any component failure involved 

in the event, not just components within the scope of EPIX or EIIS. 

Failure Continuation Sheet (NRC Form 366B): If more than four failures need to be 

coded, use one or more of the failure continuation sheets (NRC Form 366B). Code the 

entries in Items 1, 2, 3, and 6 of the failure continuation sheet to match entries of these 

items on the initial page of the LER. Complete item 13 in the same manner as item 13 

on the basic LER form. Do not repeat failures coded on the basic LER form on the 

failure continuation sheet. Place any failure continuation sheets after any text 

continuation sheets and include those sheets in the total number of pages for the LER. 

(14) Supplemental Report (NRC Form 366, Item 14) 

Check the "Yes" block if the licensee plans to submit a followup report. For example, if a failed 

component had been returned to the manufacturer for additional testing and the results of the 

test were not yet available when the LER was submitted, a followup report would be submitted.

NUREG-1022, Rev. 2 110
(15) Expected Submission Date of Supplemental Report (NRC Form 366, Item 15) 

Enter the expected date of submission of the supplemental LER, if applicable. See Section 

5.2.4(4) for the proper date format. The expected submission date is a target/planning date; it 

is not a regulatory commitment. 

(16) LER Text Continuation Sheet (NRC Form 366A) 

Use one or more additional text continuation sheets of the LER Form 366A to continue the 

narrative, if necessary. There is no limit on the number of continuation sheets that may be 

included. 

Drawings, figures, tables, photographs, and other aids may be included with the narrative to 

help readers understand the event. If possible, provide the aids on the LER form (i.e., NRC 

Form 366A). In addition, care should be taken to ensure that drawings and photographs are of 

sufficient quality to permit legible reproduction and micrographic processing. Avoid oversized 

drawings (i.e., larger than 8 1/2 x 11). 

5.2.8 Examples of LER Forms 

Examples of LER forms are provided on the following pages.

ill NUREG-1022, Rev. 2
NRC FORM 366 U.S. NUCLEAR REGULATORY APPROVED BY OMB NO. 3150-0104 EXPIRES MM-YYYY 

(MM-YYYY) COMMISSION Estimated burden per response to comply with this mandatory information collection request: 50 hrs. Reported lessons learned are incorporated into the 

licensing process and fed back to industry. Forward comments regarding burden 

LICENSEE EVENT REPORT (LER) estimatetothe Records Management Branch (T-6 F33), U.S. Nuclear Regulatory Commission, Washington. DC 20555-0001, and to the Paperwork Reduction 

Project (3150-0104), Office of Management and Budget, Washington, DC 20503. 

(See reverse for required number of If an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to 

digits/characters____________each___block) _ respond to, the information collection.I 

ILITYN 05000NIF o 

TITLE (4) 

EVENT DA1EJ (5. LER NUMBER 6 REPORT DATE (1OTHER FACILITIES INVOLVED (8) 

SEQUENTIAL REV MO DAY YEA FACILITY NAME DOCKET NUMBER 

MNUMBER YAYEAR Y NO DAY 05000 

S i i FACILITY NAME DOCKET NUMBER 

II i 05000 

OPERATING 1 THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §:((CCk all that apply) (11) 

MODE (9) J 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 

POWER 1 20.2201 (d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A• 50.73(a)(2)(viii)(Af 

LEVEL (10) _ 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 

20.2203(a)(2)(i) 50.36(c)(1 )(ifA) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 

20.2203(a) (2)(ii) 50.36(c)(1 )(ii)(A) 50.73(a)(2)(iv)LAI 50.73(a)(2)(x) 

20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2) (v).A) 73.71 (a)(4) 

20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71 (a)(5) 

20.2203(a)(2)(v) 50.73(a)(2)(i)(_. 50.73(a)(2)(v)(C) OTHER 

20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(g'2)(v'D) Specify in Abstract below or in NRC Form 366A 

LICENSEE CONTACT FOR THIS LER (12) 

NAME J TELEPHONE NUMBER (Include Area Code) 

COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS EPORT(13) 

CAUSE COMPNEN MANU- REPORTABLE CAS SYTE COPNN MANU- REPORTABLE SYSTEM COMPONENTFACTURER TO EPIX CAUSE SYSTEM COMPONENT FACTURER TO EPIX 

SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED OYA 

YES (If yes, complete EXPECTED SUBMISSION NO SUBMISSION 

DATE). I DATE (15) 

ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16) 

NRC FORM 366 (MM-YYYY)

NUREG-1022, Rev. 2 112
REQUIRED NUMBER OF DIGITS/CHARACTERS 

FOR EACH BLOCK

BLOCK NUMBER OF 

NUMBER DIGITS/CHARACTERS TITLE 

1 UP TO 46 FACILITY NAME 

2 8 TOTAL 

3 IN ADDITION TO 05000 DOCKET NUMBER 

3 VARIES PAGE NUMBER 

4 UP TO 76 TITLE 

8 TOTAL 

5 2 FOR MONTH EVENT DATE 

2 FOR DAY 

4 FOR YEAR 

9 TOTAL 

64 FOR YEAR 3 FOR SEQUENTIAL NUMBER LER NUMBER 

2 FOR REVISION NUMBER 

8 TOTAL 

7 2 FOR MONTH REPORTDATE 

2 FOR DAY 

4 FOR YEAR 

UP TO 18 - FACILITY NAME 

8 8 TOTAL-- DOCKET NUMBER OTHER FACILITIES INVOLVED 

3 IN ADDITION TO 05000 

9 1 OPERATING MODE 

10 3 POWER LEVEL 

11 VARIES 

CHECK ALL BOXES THAT APPLY REQUIREMENTS OF 10 CFR 

12 UP TO 50 FOR NAME LICENSEE CONTACT 14 FOR TELEPHONE LICENSEE__ONTACT 

CAUSE VARIES 

2 FOR SYSTEM 

13 4 FOR COMPONENT EACH COMPONENT FAILURE 

4 FOR MANUFACTURER 

EPIX VARIES 

1 

14 CHECK BOX THAT APPLIES SUPPLEMENTAL REPORT EXPECTED 

8 TOTAL 

15 2 FOR MONTH EXPECTED SUBMISSION DATE 2 FOR DAY _______ ~~4 FOR YEAR____________ ________

113 NUREG-1022, Rev. 2
NRC FORM 366A 

(MM-yyYY)

11 FACILITY NAME(

TEXT (If more space is required, use additional

U.S. NUCLEAR REGULATORY COMMISSION 

LICENSEE EVENT REPORT (LER) 

TEXT CONTINUATION

NRC FORM 366A (MM-YYYY) 

NUREG-1022, Rev. 2 114
NRC FORM 366B U.S. NUCLEAR REGULATORY COMMISSION 

(MM-YYYY) 

LICENSEE EVENT REPORT (LER) 

FAILURE CONTINUATION 

FACILITY NAME (1) DOCKET (2)II LER NUMBER (6) PAGE (3) 

YEAR SEQUENTIAL REVISION 

NUMBER NUMBER 

05000 OF 

COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

SYSTEM C N MANU- I REPORTABLE 

I FACTURER TO EPIX t I 4

*1I I 4

+ 1 4 4

4. 1 4 4.

4. 4 4 .1.

4. 4 4 4.

I CAUSE I SYSTEM ICOMPONENT MANU- REPORTABLE 

FACTURER I TO EPIX

4 1- I 4

+ 4. 1 4

4. 1 4 4.

4 4 4 +

I + 4-

_________ ________ _________ __________ I. JL ________ I. 1. _________ L L

NRC FORM 366B (MM-YYYY)

NUREG-1 022, Rev. 2

CAUSE

115
NRC FORM 335 U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER 

(2-89) (Assigned by NRC, Add Vol., Supp., Rev., 

NRCM 1102. and Addendum Numbers, if any.) 

3201, 3202 BIBLIOGRAPHIC DATA SHEET 

(See instructions on the reverse) NUREG-1022 

2. TITLE AND SUBTITLE Rev. 2 

Event Reporting Guidelines 3. DATE REPORT PUBLISHED 

10 CFR 50.72 and 50.73 3. MONTH DTE RED YEAR 

October 2000 

4. FIN OR GRANT NUMBER 

5. AUTHOR(S) 6. TYPE OF REPORT 

D.P. Allison Regulatory 

7. PERIOD COVERED (inclusive Dates) 

8. PERFORMING ORGANIZATION - NAME AND ADDRESS (If NRC, provide Division, Office or Region, U.S. Nuclear Regulatory Commission, and mailing address; if contractor, 

provide name and mailing address.) 

Division of Regulatory Improvement Programs 

Office of Nuclear Reactor Regulation 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555-0001

9. SPONSORING ORGANIZATION - NAME AND ADDRESS (if NRC, type -Same as above"; if contractor, provide NRC Division, Office or Region, U.S. Nuclear Regulatory Commission, 

and mailing address.)

Same as above.

10. SUPPLEMENTARY NOTES

11. ABSTRACT (200 words orless) 

This revision 2 to NUREG-1 022 revised the event reporting guidelines to: implement amendments to 10 CFR 50.72 and 50.73; 

and incorporate minor revisions to the guidelines for the purpose of clarification.

12. KEY WORDS/DESCRIPTORS (List words or phrases that will assist researchers in locating the report.) 13. AVAILABILITY STATEMENT 

unlimited 

Emergency Notification System unlim ited 

Event Report 14. SECURITY CLASSIFICATION 

Immediate Notification (This Page) 

Licensee Event Report unclassified 

Notification (This Report) 

Report unclassified 

15. NUMBER OF PAGES 

16. PRICE

NRC FORM 335 (2-89)
Federal Recycling Program
UNITED STATES 

NUCLEAR REGULATORY COMMISSION 

WASHINGTON, D.C. 20555-0001