IMC 0309, Reactive Inspection Decision Basis for Reactors
Reactive Inspection Decision Basis for Reactors
- Issued 12-13-23: https://www.nrc.gov/docs/ML2323/ML23234A176.pdf
- Issued 10-28-11: https://www.nrc.gov/docs/ML1118/ML111801157.pdf
Text
NRC INSPECTION MANUAL IRIB
INSPECTION MANUAL CHAPTER 0309
REACTIVE INSPECTION DECISION BASIS FOR POWER REACTORS
0309-01 PURPOSE
01.01 To provide amplifying direction and guidance to the Office of Nuclear Reactor Regulation (NRR) and the regional staff for implementing the requirements prescribed in Management Directive (MD) 8.3, “NRC Incident Investigation Program.”
01.02 To provide a detailed list of deterministic criteria that can be used on their own or in conjunction with a probabilistic risk assessment as a decision basis for implementing Incident Investigation Teams (IITs), Augmented Inspection Teams (AITs), and Special
Inspections (SIs).
01.03 To provide guidance on the use of risk metrics and probabilistic risk assessment to inform the need for a reactive inspection.
01.04 To discuss the availability of various tools to communicate with internal and external stakeholders on event response and assessment.
01.05 To provide a sample format to use when documenting reactive inspection decisions.
0309-02 BACKGROUND
It is the policy of the U.S. Nuclear Regulatory Commission (NRC) to ensure that significant events involving reactor and materials facilities licensed by the NRC are investigated in a timely, objective, systematic, and technically sound manner; that the information pertaining to each event is documented; and that the cause or causes of each event are ascertained. MD 8.3 is the agency-level governing document for this Inspection Manual Chapter (IMC). MD 8.3 includes deterministic and risk criteria for determining the agency’s appropriate event response and delineates office-level responsibilities for significant event responses. A significant event is any radiological, safeguards, or other safety-related event at an NRC-licensed facility that poses an actual or significant potential hazard to public health and safety, property, or the environment.
This IMC also refers to a significant event as an “event” or “incident.” Significant events include initiating events (e.g., complicated reactor trips) and significant degraded conditions. This IMC provides specific roles and responsibilities for the staff involved in the event response process as well as guidance for developing cooperative staff-level relationships among the participating offices. Inspection Procedure (IP) 71153, “Follow Up of Events and Notices of Enforcement Discretion,” is used to gather the information needed to evaluate events and to assess their significance. This information and the directions in this IMC are then used to make reactive inspection decisions. IP 93812, “Special Inspection,” and 93800, “Augmented Inspection Team,” provide implementing directions for reactive inspection responses. NUREG-1303, “Incident Investigation Manual,” details the procedures involved in conducting an IIT.
0309-03 RESPONSIBILITIES
03.01 Operating Experience Branch (IOEB)
IOEB is responsible for the initial NRR follow-up of significant events at power reactors and is the initial NRR point of contact to coordinate event evaluation. IOEB works with the regional offices and inspectors to develop event details. IOEB contacts appropriate technical branches and the project manager (PM) for support to address relevant technical and regulatory issues, including safety significance determinations. If an event or condition warrants headquarters involvement in the reactive inspection decision, IOEB participates in the decision-making process (see section 04.05).
03.02 Probabilistic Risk Assessment Operational Support and Maintenance Branch (APOB)
At the request of IOEB or the regional office, APOB evaluates the risk associated with
significant events at power reactors. The APOB risk analyst should seek a consensus
with the regional Senior Risk Analysts (SRAs) on the event’s risk significance so that
regional and headquarters managers receive consistent risk insights. Differences
between headquarters and regional risk assessments, that could affect the response
decision, should be explained to the decision makers. APOB provides the risk input to
NRR management through IOEB. If an event or condition warrants headquarters
involvement in the reactive inspection decision, APOB participates in the decisionmaking process (see section 04.05).
03.03 Other Technical Branches/NRR
At the request of IOEB, the Division of Operating Reactor Licensing (DORL), or the
regional offices, NRR technical branches provide technical support for resolving issues
identified during follow-up of significant events.
03.04 Division of Operating Reactor Licensing (DORL)
The DORL PM keeps abreast of significant events at assigned power reactor plant(s)
and provides logistical support for regional offices and other NRR staff during the shortterm event response. The PM promptly alerts IOEB to potentially significant events. If an event or condition warrants consideration of an AIT or IIT, the PM provides logistical
support by setting up a conference between headquarters and the regional office (see
section 04.05).
03.05 Regional Staff
The regional staff formulates recommendations to their respective Regional
Administrator (RA) regarding appropriate event response and places a completed
MD 8.3 determination in the Agencywide Documents Access and Management System
(ADAMS) once a decision is finalized. If an event or condition warrants consideration of
an AIT or IIT, staff will participate in the decision-making process (see section 04.05).
When the decision is made to launch a reactive inspection, the staff will develop an
inspection charter and place it in ADAMS.
03.06 Division of Preparedness and Response/Incident Response Directorate (DPR/IRD)
DPR/IRD is part of the Office of Nuclear Security and Incident Response (NSIR). If an
event or condition warrants consideration of an AIT or IIT, IRD will participate in the
decision-making process (see section 04.05).
The flow of communication among the participating staff organizations and the
decision-making points is depicted in figure 1.
Figure 1: Flow Chart for AIT or IIT Decision-Making
0309-04 REQUIREMENTS
04.01 Initial Event Notification and Follow-up
When NRR is notified of a potentially significant event, or an event with potential generic
implications, IOEB will coordinate initial NRR event follow-up activities, working with the
regional office to understand the significance and generic implications of the event. The
DORL PM is kept informed of the event information and provides logistical support for
further appropriate NRR event follow-up activities. IOEB requests assistance from NRR
technical staff as needed. Regional staff may request technical support from NRR by
contacting IOEB.
04.02 Risk Significance
Power reactor events are evaluated for risk significance when one or more of the
deterministic criteria listed in table 1 are met. In NRR, APOB in coordination with the
responsible regional office promptly evaluates the risk of events or degraded conditions
when the risk estimate conducted by the regional SRA is ≥1E-5 conditional core damage
probability (CCDP) or ≥1E-6 conditional large early release probability (CLERP), or when
requested by the regional staff. In such cases, all currently available event or
degraded-condition-related risk information will be promptly provided to APOB for risk
evaluation. APOB communicates with its regional counterparts (e.g., the regional SRAs)
and IOEB to share pertinent risk information to reach a consensus on the risk
significance of the event or degraded condition. The regional SRAs inform regional
management of the risk significance, and APOB provides the NRR risk input and
uncertainty estimates to NRR management, typically through IOEB. Additionally, the
Office of Nuclear Regulatory Research can provide risk analysis support upon request.
04.03 Risk Measures and Quantitative Criteria for Reactive Inspections
a. Deterministic Screening. The purpose of this deterministic screening is to eliminate the
need to perform a detailed risk assessment for events that are low risk and well
understood. Appropriately managed plant configurations due solely to planned
maintenance under applicable rules and regulations (e.g., Title 10 of the Code of Federal
Regulations (10 CFR) 50.65(a)(4); 10 CFR 50.59, “Changes, tests, and experiments”;
and technical specifications) need not be considered.
Table 1: Reactor Safety Deterministic Screening Criteria for Risk Assessment
Criteria Deterministic Screening Criteria for Risk Assessment
1 Involved operations that exceeded, or were not included in, the design bases of the
facility
2 Involved a major deficiency in design, construction, or operation having potential
generic safety implications
3 Led to a significant loss of integrity of the fuel, the primary coolant pressure
boundary, or the primary containment boundary of a nuclear reactor
4 Led to the loss of a safety function or multiple failures in systems used to mitigate
an actual event
5 Involved possible adverse generic implications
6 Involved significant unexpected system interactions
7 Involved repetitive failures or events involving safety-related equipment or
deficiencies in operations
8 Involved questions or concerns pertaining to licensee operational performance
b. Risk Assessment. Evaluate the risk of significant events or conditions at power reactors
meeting any of the deterministic screening criteria in table 1, as follows: CCDP best
reflects loss of defense in depth due to the event, regardless of whether the cause is
deficient licensee performance. CCDP accounts for actual plant configuration, including
equipment unavailable because of maintenance and testing. IMC 0609, “Significance
Determination Process,” addresses CCDP determination. Although CCDP represents a
fundamentally different concept for events than for degraded conditions that do not
initiate an event, the same guidelines may be applied to both in order to assist
management in its risk-informed decision-making.
The lack of complete event information at the time of the NRC response decision
focuses attention on the uncertainty of influential assumptions and their effect on the risk
significance. IP 71153 discusses inspector inputs to risk analyses that are needed to
understand the risk significance. In determining risk significance of an event, NRC
should assess the potential influence on risk of the following:
• dominant core damage sequence(s)
• level of confidence in failure/unavailability values assumed for the sequence(s)
• influence on the CCDP estimate of contributing factors where the confidence
level is low
Table 2 provides recommended event response thresholds as a function of CCDP. The
overlap of options relative to CCDP levels provides the opportunity to select different
inspection or investigation options on the basis of such factors as uncertainty of the risk
estimate coupled with the deterministic insights. Risk insights should also be used in
considering the number of inspectors, their expertise, and the areas of focus.
Table 2: Event Response as a Function of CCDP
Estimated CCDP
CCDP < 1E-6 1E-6 –> 1E-5 1E-5 –> 1E-4 1E-4 –> 1E-3 CCDP > 1E-3
No Additional Inspection
In addition to core damage risk, NRC should assess whether degraded conditions could
increase the likelihood of a large early release resulting from containment failure or
containment bypass. For events or degraded conditions associated with containment
performance or bypass, the risk of a large early release (e.g., the CLERP) is evaluated,
if practical, in addition to CCDP. Table 3 lists appropriate reactive inspection thresholds
as a function of CLERP.
Table 3: Event Response as a Function of CLERP
Estimated CLERP
CLERP < IE-7 1E-7 –> 1E-6 1E-6 –> 1E-5 1E-5 –> 1E-4 CLERP > 1E-4
No Additional Inspection
If the risk assessment is ≥1E-5 CCDP or ≥1E-6 CLERP, regional management will
promptly contact NRR (IOEB), as coordination with headquarters will be necessary (see
figure 1 and section 04.05).
In some cases, the adequacy of risk assessment models, assumptions, and
uncertainties may make it difficult to numerically quantify risk. In such cases,
recommendations should rely on the deterministic criteria and the NRC’s current
understanding of the event and its causes.
04.04 Deterministic Factors for Reactive Inspections
In addition to the significant events at power reactors discussed in section 04.03, there
are other significant events (related to reactor safety, radiation safety, or safeguards and
security) that may occur at an NRC-licensed facility. The factors that cause these other
types of incidents are not necessarily part of a licensee’s probabilistic risk assessment
(PRA) model, and their risk significance may not be easily quantified. Therefore, the
incidents must be examined using deterministic criteria, considering safety, margin,
defense in depth, and additional factors when deciding on the appropriate level of
reactive inspection. The NRC also considers additional factors such as openness, public
interest, and public safety as appropriate when deciding whether to dispatch an IIT, AIT,
or SI. These additional deterministic criteria are listed in section 04.05 (and in
Enclosure 2). Tables 4, 5, and 6 list these additional deterministic criteria. They are
organized by incident type (reactor safety, radiation safety, safeguards/security) and by
the reactive inspection warranted.
For these criteria, no quantitative risk assessment is required, and meeting any one of
the deterministic criteria is the basis for considering an IIT, AIT, or SI (as specified)
informed by consideration of safety, margin, defense in depth, and additional factors.
Issue Date: 12/14/23 8 0309
Table 4: Reactor Safety Deterministic Criteria
Reactor Safety—Deterministic Criteria
Criteria Consider IIT
1 Led to a site area emergency (MD 8.3)
2 Exceeded a safety limit of the licensee's technical specifications (MD 8.3)
3
Involved circumstances sufficiently complex, unique, or not well enough understood,
or involved safeguards concerns, or involved characteristics the investigation of which
would best serve the needs and interests of the Commission (MD 8.3)
Criteria Consider SI
4 Significant failure to implement the emergency preparedness program during an actual
event, including the failure to classify, notify, or augment onsite personnel
5
Involved significant deficiencies in operational performance which resulted in
degrading, challenging, or disabling a safety system function or resulted in placing the
plant in an unanalyzed condition for which available risk assessment methods do not
provide an adequate or reasonable estimate of risk
Table 5: Radiation Safety Deterministic Criteria
Radiation Safety Deterministic Criteria
Criteria Consider IIT
1
Led to a significant radiological release (levels of radiation or concentrations of
radioactive material in excess of 10 times any applicable limit in the license or
10 times the concentrations specified in 10 CFR Part 20, Appendix B, Table 2, when
averaged over a year) of byproduct, source, or special nuclear material to unrestricted
areas (MD 8.3)
2
Led to a significant occupational exposure or significant exposure to a member of the
public. In both cases, “significant” is defined as five times the applicable regulatory
limit (except for shallow-dose equivalent to the skin or extremities from discrete
radioactive particles) (MD 8.3)
3
Involved the deliberate misuse of byproduct, source, or special nuclear material from
its intended or authorized use, which resulted in the exposure of a significant number
of individuals (MD 8.3)
4 Involved byproduct, source, or special nuclear material, which may have resulted in a
Issue Date: 12/14/23 9 0309
Radiation Safety Deterministic Criteria
5
Involved circumstances sufficiently complex, unique, or not well enough understood,
or involved safeguards concerns, or involved characteristics the investigation of which
would best serve the needs and interests of the Commission (MD 8.3)
Criteria Consider AIT
6
Led to a radiological release of byproduct, source, or special nuclear material to
unrestricted areas that resulted in occupational exposure or exposure to a member of
the public in excess of the applicable regulatory limit (except for shallow-dose
equivalent to the skin or extremities from discrete radioactive particles) (MD 8.3)
7
Involved the deliberate misuse of byproduct, source, or special nuclear material from
its intended or authorized use and had the potential to cause an exposure of greater
than 5 rem to an individual or 500 mrem to an embryo or fetus (MD 8.3)
8
Involved the failure of radioactive material packaging that resulted in external radiation
levels exceeding 10 rads/hr or contamination of the packaging exceeding 1000 times
the applicable limits specified in 10 CFR 71.87 (MD 8.3)
9 Involved the failure of the dam for mill tailings with substantial release of tailings
material and solution off site (MD 8.3)
Criteria Consider SI
10
May have led to an exposure in excess of the applicable regulatory limits, other than
via the radiological release of byproduct, source, or special nuclear material to the
unrestricted area; specifically
• occupational exposure in excess of the regulatory limits in 10 CFR 20.1201
• exposure to an embryo/fetus in excess of the regulatory limits in
• exposure to a member of the public in excess of the regulatory limits in
10
May have led to an unplanned occupational exposure in excess of 40 percent of the
applicable regulatory limit (excluding shallow-dose equivalent to the skin or extremities
from discrete radioactive particles)
11 Led to unplanned changes in restricted area dose rates in excess of 20 rem per hour
in an area where personnel were present or which is accessible to personnel
12
Led to unplanned changes in restricted area airborne radioactivity levels in excess of
500 derived air concentration (DAC) in an area where personnel were present or
which is accessible to personnel and where the airborne radioactivity level was not
promptly recognized and/or appropriate actions were not taken in a timely manner
Radiation Safety Deterministic Criteria
13
Led to an uncontrolled, unplanned, or abnormal release of radioactive material to the
unrestricted area
• for which the extent of the offsite contamination is unknown; or,
• that may have resulted in a dose to a member of the public from loss of
radioactive material control in excess of 25 mrem (10 CFR 20.1301(e)); or,
• that may have resulted in an exposure to a member of the public from effluents
in excess of the as low as reasonably achievable (ALARA) guidelines contained
in Appendix I to 10 CFR Part 50
14
Led to a large (typically greater than 100,000 gallons), unplanned release of
radioactive liquid inside the restricted area that has the potential for ground-water, or
offsite, contamination
15
Involved the failure of radioactive material packaging that resulted in external radiation
levels exceeding 5 times the accessible area dose rate limits specified in
10 CFR Part 71, or 50 times the contamination limits specified in 49 CFR Part 173
16
Involved an emergency or non-emergency event or situation, related to the health and
safety of the public or on-site personnel or protection of the environment, for which a
10 CFR 50.72 report has been submitted that is expected to cause significant,
heightened public or government concern
Table 6: Security Deterministic Criteria
Security Deterministic Criteria
Criteria Consider IIT
1
Involved circumstances sufficiently complex, unique, or not well enough understood,
or involved safeguards concerns, or involved characteristics the investigation of which
would best serve the needs and interests of the Commission (MD 8.3)
2 Failure of licensee significant safety equipment or adverse impact on licensee
operations as a result of a safeguards initiated event (e.g., tampering)
3 Actual intrusion into the protected area
Criteria Consider AIT
4 Involved a significant infraction or repeated instances of safeguards infractions that
demonstrate the ineffectiveness of facility security provisions (MD 8.3)
5 Involved repeated instances of inadequate nuclear material control and accounting
provisions to protect against theft or diversions of nuclear material (MD 8.3)
6 Confirmed tampering event involving significant safety or security equipment
7
Substantial failure in the licensee’s intrusion detection or package/personnel search
procedures which results in a significant vulnerability or compromise of plant safety or
security
Criteria Consider SI
8
Involved inadequate nuclear material control and accounting provisions to protect
against theft or diversion, as evidenced by inability to locate an item containing special
nuclear material (such as an irradiated rod, rod piece, pellet, or instrument)
9 Involved a significant safeguards infraction that demonstrates the ineffectiveness of
facility security provisions
10 Confirmation of lost or stolen weapon
11 Unauthorized, actual non-accidental discharge of a weapon within the protected area
12 Substantial failure of the intrusion detection system (not weather related)
13
Failure to the licensee’s package/personnel search procedures which results in
contraband or an unauthorized individual being introduced into the protected area
14
Potential tampering or vandalism event involving significant safety or security
equipment where questions remain regarding licensee performance/response or a
need exists to independently assess the licensee’s conclusion that tampering or
vandalism was not a factor in the condition(s) identified
04.05 Recommendation and Decision
If the review of the event under sections 04.03 and 04.04 yields an SI, the RA will decide
whether to initiate the SI. In this case, regional management may consult with NRR and
NSIR but is not required to do so.
If the review of the event under section 4.03 and 04.04 yields an AIT recommendation or
falls within the SI/AIT overlap region, the regional staff shall promptly contact IOEB and
provide event details. IOEB will direct the DORL PM to coordinate a conference with
representatives from the regional office, DORL, APOB, IOEB, and NSIR/DPR to discuss
whether an SI or AIT is more appropriate. In such cases, the RA, in consultation with the
NRR Office Director and NSIR Office Director, makes the final decision on whether to
If the review of the event under section 4.03 and 04.04 yields an IIT recommendation or
falls within the AIT/IIT overlap region, the Directors of NRR and NSIR will consult with
the RA and provide a recommendation to the Executive Director for Operations (EDO).
In such cases, the EDO, in consultation with the RA, will make the ultimate decision on
whether to proceed with an AIT or IIT.
The regional office will notify the licensee of its intentions once a final decision is made
04.06 Documentation
Enclosure 1 provides a form for regional personnel to use when documenting their
decision whether to pursue a reactive inspection based on evaluation of the deterministic
and risk criteria in section 04.03. Enclosure 2 provides a form for regional personnel to
use when documenting their decision whether to pursue a reactive inspection based on
evaluation of the deterministic criteria in section 04.04. To fully document the basis for
not performing a reactive inspection, both enclosures 1 and 2 should be completed. As
noted in enclosure 2, the regions may customize the form to fit regional protocols, but
the deterministic criteria should not be changed. The form, along with specific
instructions for its completion by regional staff, should be included in regional office
instructions or implementing procedures. Basic guidelines include:
• As appropriate and known, describe the event or degraded conditions, apparent
system interactions, operational responses, impacts on safety and safety functions,
site conditions, and modes of operation in the Brief Description of the Significant
Event or Degraded Condition section. Reference any event notifications received in
response to the event or degraded condition.
• If none of the deterministic criteria were met, provide sufficient detail to justify the
conclusion in the criteria Remarks section as appropriate. Also, state that no
deterministic criteria were met in the Response Decision section of the form.
• If one or more of the deterministic criteria were met, provide sufficient detail to justify
the conclusion in the criteria Remarks section. When applicable under section 04.03,
request an SRA perform a risk assessment and document results in the Conditional
Risk Assessment section of the form.
Issue Date: 12/14/23 13 0309
• Avoid documenting a commitment to perform additional event-related inspection
when the MD 8.3 evaluation determines no additional reactive inspection is
warranted.
• Additional guidance for when it may be appropriate to not perform an MD 8.3
evaluation as well as examples of completed MD 8.3 evaluations are included in
exhibit 1.
After documenting the agency’s reactive inspection decision, its basis, and a sufficient
response for each criterion, place the documented decision in ADAMS and profile using
template “NRR-123: Management Directive (MD) 8.3, Reactive Inspection Evaluation”
(ML18233A547) generally no more than 7 calendar days after the event or discovery of
the degraded condition. Submit the document to the Document Processing Center after
it is either determined that the document is sensitive or, when non-sensitive, coincident
with the publication of the associated inspection report documenting related inspection.
[C1]
04.07 Inspection Charter
The purpose of the charter is to delineate the general scope of the reactive inspection
and to facilitate fact gathering and understanding. Available risk insights and apparent
causal indications should be used to develop the charter’s scope. The charter may
reasonably include an examination of the conditions preceding the event, event
chronology, system responses, human factors, safety culture, equipment performance,
quality assurance, radiological considerations, safeguards considerations, event
precursors, event response, operating experience, and safety or security impacts in
determining the causes of the significant event and in support of appropriate agency
follow-up actions. The charter should assess immediate corrective actions and
compensatory measures taken to address immediate safety or security concerns. The
charter should be consistent with the risk insights and the event’s complexity.
Reactive inspections are focused on fact-gathering and a thorough independent review
of events. When the inspection is complete, the inspector should consider providing
feedback to headquarters on any suggested changes to prevent or reduce the frequency
of the significant events or enhance oversight processes.
The charter should not attempt to assess the adequacy of any longer-term corrective
actions used to improve licensee performance and prevent recurrence of significant
conditions, as these follow-up activities are addressed using supplemental or baseline
inspections. Performing these activities during a reactive inspection may delay prompt
dissemination of the facts and circumstances surrounding the significant event and
impose an unwarranted regulatory burden on licensees.
For SIs and AITs, the inspection charter is generally communicated as an enclosure to a
memorandum from the RA to the leader, with copies provided to the NRR office director,
Office of Public Affairs (OPA), Regional Public Affairs Officer, affected licensee, and
NSIR office director when related to security or emergency planning. The charter may be
modified during a reactive inspection in consultation with management, if the inspection
develops significant new information that warrants review.
04.08 Communications
Communication tools that are available to enhance the effectiveness and efficiency of
the agency’s communications with its stakeholders. The NRC has developed the “Event
Response and Assessment Communications Plan,” which is available in the ADAMS
Main Library internal folder entitled “Communication Plans.”
The communication tools available for event or degraded condition response and
assessment include the following:
• a communications team
• central tracking of controlled correspondence
• a notification sequence for significant regulatory documents
• formalized questions and answers for common and expected significant events for
use by the OPA during initial event response
• a dedicated web page for each event
If it is determined that a communications team is warranted, DORL typically plays the
key NRR role in developing and coordinating the communications team and subsequent
communications activities. Specific communication activity assignments are determined
by the communications team. IOEB, the Regional Offices, and other NRR branches
support such DORL activities, as needed. Communication activities typically continue
beyond the initial phase of investigative response until their goals have been
accomplished.
Reactive inspections may generate high public interest. The RA in consultation with the
OPA, may elect to open a reactive inspection exit meeting to the public. Alternately, the
RA may decide it is more appropriate to have a separate public meeting, press
conference, or both in lieu of a public meeting with the licensee.
04.09 Allegations
If, during the course of evaluating events using this procedure, the inspector(s) suspect
that there might be an element of willfulness or intentional wrongdoing, they will
(1) prepare and submit an allegation receipt form to the appropriate regional office with
the inspector(s) as the concerned individual(s), (2) inform the appropriate regional
manager(s) of the suspicion, and (3) handle the potential willfulness or intentional
wrongdoing in accordance with the allegation process. This should be done regardless
of whether a reactive inspection is conducted.
0309-05 REFERENCES
“Event Response and Assessment Communications Plan,” October 3, 2000 (ML003774969)
IMC 0609, “Significance Determination Process”
IP 71153, “Follow Up of Events and Notices of Enforcement Discretion”
Issue Date: 12/14/23 15 0309
IP 93800, “Augmented Inspection Team”
IP 93812, “Special Inspection”
MD 8.2, “NRC Incident Response Program”
MD 8.3, “NRC Incident Investigation Program”
NUREG-1303, “Incident Investigation Manual”
END
Exhibit 1: Additional Guidance and Examples
Below is a list of events and conditions that generally would not warrant an MD 8.3 evaluation
unless they are exacerbated by other issues that contributed to those events and conditions or
complexities that occurred because of those events and conditions:
1. Uncomplicated reactor trips or scrams (manual or auto).
2. Scaffolding found to have potentially impacted only a single safety related system operation.
3. Safety system instrumentation found out of calibration via periodic testing or surveillance.
4. Inadvertent discharge of Freon, fire water, carbon dioxide or Halon having no adverse
impact on plant operations.
5. Tritium leaks found because of scheduled testing or investigation by the licensee.
6. Loss of spent fuel cooling with little or no pool temperature rise (delta of 15ºF and highest
temp below 140ºF).
7. Balance of plant transients that do not result in a plant trip/scram.
8. Short-term losses of shutdown cooling/decay heat removal which were readily recovered
(Less than 20 percent of Margin to Time to Boil).
9. Isolated surveillance testing failures (not readily known to be repetitive, generic, or common
mode in nature).
10. Loss of secondary containment (BWR).
Examples of MD 8.3 determinations [C2]:
Search ADAMS for Document Type “MD 8.3 Reactive Inspection Evaluation”
Issue Date: 12/14/23 Encl1-1 0309
Enclosure 1: Decision Documentation for Reactive Inspection
(Deterministic and Risk Criteria Analyzed)
Decision Documentation for Reactive Inspection
(Deterministic and Risk Criteria Analyzed)
PLANT: EVENT DATE: EVALUATION DATE:
Brief Description of the Significant Event or Degraded Condition:
Y/N DETERMINISTIC CRITERIA
Involved operations that exceeded, or were not included in, the design bases of the
facility
Remarks:
Involved a major deficiency in design, construction, or operation having potential
generic safety implications
Remarks:
Led to a significant loss of integrity of the fuel, primary coolant pressure boundary, or
primary containment boundary of a nuclear reactor
Remarks:
Led to the loss of a safety function or multiple failures in systems used to mitigate an
actual event
Remarks:
Involved possible adverse generic implications
Remarks:
Involved significant unexpected system interactions
Remarks:
Involved repetitive failures or events involving safety-related equipment or deficiencies
in operations
Remarks:
Involved questions or concerns pertaining to licensee operational performance
Remarks:
Issue Date: 12/14/23 Encl1-2 0309
CONDITIONAL RISK ASSESSMENT
RISK ANALYSIS BY: DATE:
Brief Description of the Basis for the Assessment (may include assumptions, calculations,
references, peer review, or comparison with licensee’s results):
The estimated conditional core damage probability (CCDP) is ___________________ and
places the risk in the range of a _______________ and ____________________ inspection.
Issue Date: 12/14/23 Encl1-3 0309
RESPONSE DECISION
USING THE ABOVE INFORMATION AND OTHER KEY ELEMENTS OF CONSIDERATION
AS APPROPRIATE, DOCUMENT THE RESPONSE DECISION TO THE EVENT OR
CONDITION, AND THE BASIS FOR THAT DECISION
DECISION AND DETAILS OF THE BASIS FOR THE DECISION:
BRANCH CHIEF REVIEW: DATE:
DIVISION DIRECTOR REVIEW: DATE:
ADAMS ACCESSION NUMBER:
EVENT NOTIFICATION REPORT NUMBER (as applicable):
Profiled using template NRR-123 (ML18233A547)
Note: The above tables are provided as examples only. The regions have discretion to modify
these tables in their implementing procedures or office instructions.
Issue Date: 12/14/23 Encl2-1 0309
Enclosure 2: Decision Documentation for Reactive Inspection and Examples
(Deterministic-only Criteria Analyzed)
Decision Documentation for Reactive Inspection
(Deterministic-only Criteria Analyzed)
PLANT: EVENT DATE: EVALUATION DATE:
Brief Description of the Significant Event or Degraded Condition:
REACTOR SAFETY
Y/N IIT Deterministic Criteria
Led to a Site Area Emergency
Remarks:
Exceeded a safety limit of the licensee's technical specifications
Remarks:
Involved circumstances sufficiently complex, unique, or not well enough understood,
or involved safeguards concerns, or involved characteristics the investigation of
which would best serve the needs and interests of the Commission
Remarks:
Y/N SI Deterministic Criteria
Significant failure to implement the emergency preparedness program during an
actual event, including the failure to classify, notify, or augment onsite personnel
Remarks:
Involved significant deficiencies in operational performance which resulted in
degrading, challenging, or disabling a safety system function or resulted in placing
the plant in an unanalyzed condition for which available risk assessment methods
do not provide an adequate or reasonable estimate of risk.
Remarks:
Issue Date: 12/14/23 Encl2-2 0309
RADIATION SAFETY
Y/N IIT Deterministic Criteria
Led to a significant radiological release (levels of radiation or concentrations of
radioactive material in excess of 10 times any applicable limit in the license or 10
times the concentrations specified in 10 CFR Part 20, Appendix B, Table 2, when
averaged over a year) of byproduct, source, or special nuclear material to
unrestricted areas
Remarks:
Led to a significant occupational exposure or significant exposure to a member of
the public. In both cases, “significant” is defined as five times the applicable
regulatory limit (except for shallow-dose equivalent to the skin or extremities from
discrete radioactive particles)
Remarks:
Involved the deliberate misuse of byproduct, source, or special nuclear material from
its intended or authorized use, which resulted in the exposure of a significant
number of individuals
Remarks:
Involved byproduct, source, or special nuclear material, which may have resulted in
a fatality
Remarks:
Involved circumstances sufficiently complex, unique, or not well enough understood,
or involved safeguards concerns, or involved characteristics the investigation of
which would best serve the needs and interests of the Commission
Remarks:
Y/N AIT Deterministic Criteria
Led to a radiological release of byproduct, source, or special nuclear material to
unrestricted areas that resulted in occupational exposure or exposure to a member
of the public in excess of the applicable regulatory limit (except for shallow-dose
equivalent to the skin or extremities from discrete radioactive particles)
Remarks:
Issue Date: 12/14/23 Encl2-3 0309
Involved the deliberate misuse of byproduct, source, or special nuclear material from
its intended or authorized use and had the potential to cause an exposure of greater
than 5 rem to an individual or 500 mrem to an embryo or fetus
Remarks:
Involved the failure of radioactive material packaging that resulted in external
radiation levels exceeding 10 rads/hr or contamination of the packaging exceeding
1000 times the applicable limits specified in 10 CFR 71.87
Remarks:
Involved the failure of the dam for mill tailings with substantial release of tailings
material and solution off site
Remarks:
Y/N SI Deterministic Criteria
May have led to an exposure in excess of the applicable regulatory limits, other than
via the radiological release of byproduct, source, or special nuclear material to the
unrestricted area; specifically
• occupational exposure in excess of the regulatory limits in 10 CFR 20.1201
• exposure to an embryo/fetus in excess of the regulatory limits in
• exposure to a member of the public in excess of the regulatory limits in
Remarks:
May have led to an unplanned occupational exposure in excess of 40 percent of the
applicable regulatory limit (excluding shallow-dose equivalent to the skin or
extremities from discrete radioactive particles)
Remarks:
Led to unplanned changes in restricted area dose rates in excess of 20 rem per hour
in an area where personnel were present or which is accessible to personnel
Remarks:
Led to unplanned changes in restricted area airborne radioactivity levels in excess of
500 DAC in an area where personnel were present or which is accessible to
personnel and where the airborne radioactivity level was not promptly recognized
and/or appropriate actions were not taken in a timely manner
Remarks:
Issue Date: 12/14/23 Encl2-4 0309
Led to an uncontrolled, unplanned, or abnormal release of radioactive material to the
unrestricted area
• for which the extent of the offsite contamination is unknown; or,
• that may have resulted in a dose to a member of the public from loss of
radioactive material control in excess of 25 mrem (10 CFR 20.1301(e)); or,
• that may have resulted in an exposure to a member of the public from
effluents in excess of the ALARA guidelines contained in Appendix I to
Remarks:
Led to a large (typically greater than 100,000 gallons), unplanned release of
radioactive liquid inside the restricted area that has the potential for ground-water, or
offsite, contamination
Remarks:
Involved the failure of radioactive material packaging that resulted in external
radiation levels exceeding 5 times the accessible area dose rate limits specified in
10 CFR Part 71, or 50 times the contamination limits specified in 49 CFR Part 173
Remarks:
Involved an emergency or non-emergency event or situation, related to the health
and safety of the public or on-site personnel or protection of the environment, for
which a 10 CFR 50.72 report has been submitted that is expected to cause
significant, heightened public or government concern
Remarks:
Issue Date: 12/14/23 Encl2-5 0309
SAFEGUARDS/SECURITY
Y/N IIT Deterministic Criteria
Involved circumstances sufficiently complex, unique, or not well enough understood,
or involved safeguards concerns, or involved characteristics the investigation of
which would best serve the needs and interests of the Commission
Remarks:
Failure of licensee significant safety equipment or adverse impact on licensee
operations as a result of a safeguards initiated event (e.g., tampering).
Remarks:
Actual intrusion into the protected area
Remarks:
Y/N AIT Deterministic Criteria
Involved a significant infraction or repeated instances of safeguards infractions that
demonstrate the ineffectiveness of facility security provisions
Remarks:
Involved repeated instances of inadequate nuclear material control and accounting
provisions to protect against theft or diversions of nuclear material
Remarks:
Confirmed tampering event involving significant safety or security equipment
Remarks:
Substantial failure in the licensee’s intrusion detection or package/personnel search
procedures which results in a significant vulnerability or compromise of plant safety
or security
Remarks:
Issue Date: 12/14/23 Encl2-6 0309
Y/N SI Deterministic Criteria
Involved inadequate nuclear material control and accounting provisions to protect
against theft or diversion, as evidenced by inability to locate an item containing
special nuclear material (such as an irradiated rod, rod piece, pellet, or instrument)
Remarks:
Involved a significant safeguards infraction that demonstrates the ineffectiveness of
facility security provisions
Remarks:
Confirmation of lost or stolen weapon
Remarks:
Unauthorized, actual non-accidental discharge of a weapon within the protected
area
Remarks:
Substantial failure of the intrusion detection system (not weather related)
Remarks:
Failure to the licensee’s package/personnel search procedures which results in
contraband or an unauthorized individual being introduced into the protected area
Remarks:
Potential tampering or vandalism event involving significant safety or security
equipment where questions remain regarding licensee performance/response or a
need exists to independently assess the licensee’s conclusion that tampering or
vandalism was not a factor in the condition(s) identified
Remarks:
Issue Date: 12/14/23 Encl2-7 0309
RESPONSE DECISION
USING THE ABOVE INFORMATION AND OTHER KEY ELEMENTS OF CONSIDERATION
AS APPROPRIATE, DOCUMENT THE RESPONSE DECISION TO THE EVENT OR
CONDITION, AND THE BASIS FOR THAT DECISION
DECISION AND DETAILS OF THE BASIS FOR THE DECISION:
BRANCH CHIEF REVIEW: DATE:
DIVISION DIRECTOR REVIEW: DATE:
ADAMS ACCESSION NUMBER:
EVENT NOTIFICATION REPORT NUMBER (as applicable):
Profiled using template NRR-123 (ML18233A547 (non-public))
Note: The above tables are provided as examples only. The regions have discretion to modify
these tables in their implementing procedures or office instructions.
Issue Date: 12/14/23 Att1-1 0309
Attachment 1: Revision History for IMC 0309
Commitment
Tracking
Number
Accession
Number
Issue Date
Change Notice
Description of Change Description of
Training /
Knowledge
Management
Required and
Completion
Date
Comment Resolution
and Closed
Feedback Form
Accession Number
(Pre-Decisional, NonPublic Information)
11/05/03
CN 03-036
Initial Issue. Provides guidance for implementing
Management Directive 8.3, "NRC Incident Investigation
Program," at operating power reactors.
N/A N/A
N/A 09/12/06 Revision history reviewed for the last four years. N/A N/A
N/A ML070860410
04/04/07
CN 07-012
IMC 0309 is revised to provide deterministic criteria for
performing reactive inspections in areas such as reactor
safety, radiation safety, and safeguards/security.
Deterministic and risk-informed decision criteria from MD 8.3
are included in IMC 0309. Enclosures 1 and 2 are added to
provide a sample format for documenting reactive inspection
decisions.
None ML070860416
N/A ML072550088
01/10/08
CN 08-002
Defines the SI/AIT risk overlap region as the basis for region
interaction with NRR, and NSIR in determining the level of
event response. Provides deterministic criteria for events
involving potential tampering with safety or security related
equipment.
None ML073370664
N/A ML082820075
03/23/09
CN 09-010
Enclosures 1 and 2 when deciding not to perform a reactive
inspection. Delete 2 IIT deterministic criteria that are
redundant with MD 8.10.
None ML082820096
N/A ML092790408
02/02/10
CN 10-004
Added guidance on holding public meetings and established
a mailbox for MD 8.3 evaluations and reactive inspection
charters.
Issue Date: 12/14/23 Att1-2 0309
Commitment
Tracking
Number
Accession
Number
Issue Date
Change Notice
Description of Change Description of
Training /
Knowledge
Management
Required and
Completion
Date
Comment Resolution
and Closed
Feedback Form
Accession Number
(Pre-Decisional, NonPublic Information)
N/A ML111801157
10/28/11
CN 11-023
Added additional deterministic criteria to cover significant
operational performance issues where risk assessment tools
do not provide reasonable estimates of risk (FF 0309-1650).
Added vandalism to the deterministic criteria for security (FF
0309-1414) and expanded the scope of the consideration to
events involving safety and security significance for security
events (FF 0309-1616).
C1 & C2 ML23234A176
12/14/23
Added a 7-day time requirement for completing MD 8.3
evaluations. Implemented OIG-23-A-06 audit
(ML23130A375) recommendations 1 and 2 as accepted by
management in (ML23157A268 non-public) to publicly share
non-sensitive reactive inspection decisions [C1] and to
provide examples [C2]. Added guidance for charter
development and allegations. Reorganized and reformatted.
None ML23277A255
None