Dr. Mario V. Bonaca, Chairman April 29, 2003

Advisory Committee on Reactor Safeguards

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555

SUBJECT: REACTOR OVERSIGHT PROCESS

Dear Dr. Bonaca:

The purpose of this letter is to provide the staff’s response to the March 13, 2003, letter from

the Advisory Committee on Reactor Safeguards (ACRS) clarifying the Committee’s views on

the Reactor Oversight Process (ROP). In addition, this letter provides a status of the staff’s

actions and plans to address the staff requirements memorandum (SRM), dated December 20,

2001, that stated “the staff, with ACRS input, should provide recommendations for resolving, in

a transparent manner, apparent conflicts and discrepancies between aspects of the revised

reactor oversight process that are risk-informed (e.g., the significance determination process)

and those that are performance-based (e.g., the performance indicators).” 

Most of the issues noted by the ACRS in the March 13 letter were discussed at the various

briefings and in written correspondence that we provided to the Committee during the past year

of ROP implementation. As you noted, however, there are still disagreements between the

staff and the ACRS and further discussions are warranted. The staff informed the Commission

of its position and plans to address the December 2001 SRM in SECY-03-0062, “Reactor

Oversight Process Self-Assessment for Calendar Year 2002,” dated April 21, 2003.

The staff agrees that the consolidated list of issues in the March 13 letter should serve as the

basis for further discussion. The staff’s responses to the specific comments in the March 13

letter are provided below to support these discussions.

1. The purpose of the ROP is to assess safety performance so that the agency can take

appropriate action.

The staff agrees with this statement.

2. The ROP is risk-informed because it focuses on performance areas and indicators that

affect safety.

The staff agrees that the ROP inspection and performance indicator programs are

intended to focus on issues affecting safety. The ROP is also risk-informed because it

incorporates risk information into the ROP decision-making process to the extent that

the risk information is available and applicable.
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3. It is incorrect to base thresholds for PIs on risk metrics such as CDF (changes in core

damage frequency) and LERF (changes in large early release frequency). 

See the response to comment 4.

4. The thresholds separating all the performance levels (colors) should be performancebased and determined by expert judgement similar to the selection of the current

green/white thresholds.

The staff understands the Committee’s view that PI color thresholds could have been

based on the degree of deviation from average industry performance (without any

connection to risk metrics). However, to establish a closer tie between agency action

and public health and safety, the ROP was designed to be risk-informed whenever

possible. In addition, performance indicators are not intended to be exact measures of

risk or performance, but simply to be indicative of performance problems that warrant

further attention to assess their root cause and extent of condition. The staff bases the

thresholds for both the PIs and the significance determination processes (SDPs) on the

best available information, including risk information if applicable. Based on experience

to date, the staff believes that the PI thresholds are providing the necessary information

to enable the staff to make informed decisions and take appropriate actions. 

Therefore, the staff does not plan to make any near-term changes to the PI thresholds,

but will continue to monitor and assess these thresholds as part of the ongoing selfassessment activities.

5. The principal role for the SDP is to assign risk characterization to inspection findings -

not to be an evaluation of performance.

The staff agrees that the SDP assigns a significance characterization to inspection

findings, but that not all SDP thresholds are based on risk metrics. A more precise

statement is that the SDP incorporates risk insights to the extent they are available and

applicable. In all cases, the thresholds should achieve a consistent regulatory response

across all cornerstones. Every inspection finding represents deficient performance by

definition; thus the SDP provides a significance evaluation of each performance

deficiency identified.

6. PIs are needed for the cross-cutting issues and their development should be pursued by

the staff.

The staff agrees that it should consider whether further actions are warranted when

substantive cross-cutting issues are identified. Accordingly, the staff has begun to

consider more precise methods for measuring and responding to cross-cutting issues. 

This concern was also identified by the Davis-Besse Lessons Learned Task Force and

the SDP Task Group and is being tracked by the respective action plans.
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7. The Action Matrix should reflect the complementary results of the performance

assessment and the SDP.

The staff agrees with this statement. The Action Matrix does reflect the complementary

results of the performance indicators and inspection findings (using the SDP), and

determines the appropriate staff response based on this consolidation. In fact, an

underlying principle of the ROP is that crossing a PI or inspection finding threshold will

have similar meaning with respect to subsequent NRC action regardless of the

cornerstone or whether it is a PI or an inspection finding.

8. Lack of parity among the thresholds may result in suboptimal allocation of NRC and

licensee resources.

The staff agrees with this statement. The staff conducts mid-cycle reviews, end-of-cycle

(EOC) reviews, EOC summary meetings, the Agency Action Review Meeting (AARM),

and the annual Commission meeting to review agency actions and confirm that they

represent a consistent and appropriate use of NRC resources. As part of the annual

self-assessment and in preparation for the AARM, the staff considers the collection of

greater-than-green findings and PIs and presents the data to the senior managers in

order to reveal any obvious inconsistencies and a lack of parity. In addition, the staff

continually reassesses the thresholds within cornerstones to determine if changes are

warranted based on lessons learned. For instance, based on stakeholder feedback, the

Public Radiation Safety SDP was revised to clarify the appropriate green/white

threshold.

The staff will continue to interact with the ACRS on these issues as the ROP evolves.

 Sincerely,

/RA/

William D. Travers

Executive Director

 for Operations

cc: Chairman Diaz

Commissioner Dicus

Commissioner McGaffigan

Commissioner Merrifield

SECY
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7. The Action Matrix should reflect the complementary results of the performance

assessment and the SDP.

The staff agrees with this statement. The Action Matrix does reflect the complementary

results of the performance indicators and inspection findings (using the SDP), and

determines the appropriate staff response based on this consolidation. In fact, an

underlying principle of the ROP is that crossing a PI or inspection finding threshold will

have similar meaning with respect to subsequent NRC action regardless of the

cornerstone or whether it is a PI or an inspection finding.

8. Lack of parity among the thresholds may result in suboptimal allocation of NRC and

licensee resources.

The staff agrees with this statement. The staff conducts mid-cycle reviews, end-of-cycle

(EOC) reviews, EOC summary meetings, the Agency Action Review Meeting (AARM),

and the annual Commission meeting to review agency actions and confirm that they

represent a consistent and appropriate use of NRC resources. As part of the annual

self-assessment and in preparation for the AARM, the staff considers the collection of

greater-than-green findings and PIs and presents the data to the senior managers in

order to reveal any obvious inconsistencies and a lack of parity. In addition, the staff

continually reassesses the thresholds within cornerstones to determine if changes are

warranted based on lessons learned. For instance, based on stakeholder feedback, the

Public Radiation Safety SDP was revised to clarify the appropriate green/white

threshold.

The staff will continue to interact with the ACRS on these issues as the ROP evolves.

Sincerely,

/RA/

William D. Travers

Executive Director

 for Operations

cc: Chairman Diaz

Commissioner Dicus

Commissioner McGaffigan

Commissioner Merrifield

SECY

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DATE 04/11/03 04/11/03 04/29/03

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