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U.S. NUCLEAR REGULATORY COMMISSION October 2008

Revision 3 

REGULATORY GUIDE

OFFICE OF NUCLEAR REGULATORY RESEARCH

The NRC issues regulatory guides to describe and make available to the public methods that the NRC staff considers acceptable 

for use in implementing specific parts of the agency’s regulations, techniques that the staff uses in evaluating specific problems 

or postulated accidents, and data that the staff needs in reviewing applications for permits and licenses. Regulatory guides are not 

substitutes for regulations, and compliance with them is not required. Methods and solutions that differ from those set forth in 

regulatory guides will be deemed acceptable if they provide a basis for the findings required for the issuance or continuance of a 

permit or license by the Commission. 

This guide was issued after consideration of comments received from the public. 

Regulatory guides are issued in 10 broad divisions—1, Power Reactors; 2, Research and Test Reactors; 3, Fuels and Materials 

Facilities; 4, Environmental and Siting; 5, Materials and Plant Protection; 6, Products; 7, Transportation; 8, Occupational Health; 

9, Antitrust and Financial Review; and 10, General. 

Electronic copies of this guide and other recently issued guides are available through the NRC’s public Web site under the 

Regulatory Guides document collection of the NRC’s Electronic Reading Room at 

http://www.nrc.gov/reading-rm/doc-collections/ and through the NRC’s Agencywide Documents Access and Management 

System (ADAMS) at http://www.nrc.gov/reading-rm/adams.html, under Accession No. ML082380236.

REGULATORY GUIDE 1.114 

(Draft was issued as DG-1194, dated January 2008) 

GUIDANCE TO OPERATORS AT THE CONTROLS AND 

TO SENIOR OPERATORS IN THE CONTROL ROOM 

OF A NUCLEAR POWER UNIT 

A. INTRODUCTION 

This guide describes a method that the staff of the U.S. Nuclear Regulatory Commission (NRC) 

considers acceptable for use in complying with Commission regulations that require the presence of an 

operator at the controls of a nuclear power unit and the presence of a senior operator in the control room 

from which the nuclear power unit is being operated. In addition, this regulatory guide clarifies and 

provides guidance on the acceptable boundaries of the control room. The “vital area,” as defined in 

Title 10, Section 73.2, “Definitions,” of the Code of Federal Regulation (10 CFR 73.2) and in 

10 CFR 73.55(c), serves as the basis for the “control room vital area” as used in this regulatory guide. 

In accordance with 10 CFR 50.54(k), an operator or senior operator who is licensed pursuant to 

10 CFR Part 55, “Operators’ Licenses,” must be present at the controls at all times during the operation of 

a facility. General Design Criterion 19, “Control Room,” of Appendix A, “General Design Criteria for 

Nuclear Power Plants,” to 10 CFR Part 50, “Domestic Licensing of Production and Utilization Facilities,” 

requires, in part, that a control room be provided from which actions can be taken to operate the nuclear 

power unit safely under normal conditions and to maintain the nuclear power plant in a safe condition 

under accident conditions. As defined in 10 CFR 50.2, “Definitions,” and 10 CFR 55.4, “Definitions,” 

the term “controls,” when used with respect to nuclear reactors, means apparatus and mechanisms, the 

manipulation of which directly affects the reactivity or power level of the reactor. Under 

10 CFR 50.54(m)(2)(iii), when a nuclear power unit is in an operational mode other than cold shutdown 

or refueling, as defined by the unit’s technical specifications, each licensee must have a person possessing 

an active senior operator license for the nuclear power unit present in the control room at all times. In 
Rev. 3 of RG 1.114, Page 2 

addition to this senior operator, a licensed operator or senior operator must be present at the controls at all 

times for each fueled nuclear power unit. 

This regulatory guide contains information collection requirements covered by 10 CFR Part 50, 

10 CFR Part 55, and 10 CFR Part 73 that the Office of Management and Budget (OMB) approved under 

OMB control numbers 3150-0011, 3150-0018, and 3150-0002, respectively. The NRC may neither 

conduct nor sponsor, and a person is not required to respond to, an information request or requirement 

unless the requesting document displays a currently valid OMB control number. 

B. DISCUSSION 

1. Operator at the Controls 

Operating experience has shown that a need exists for guidance on acceptable methods of 

complying with the Commission’s requirement that an operator must be present at the controls of a 

facility. The operator at the controls of a nuclear power unit has many responsibilities including the 

following: 

• adhering to the unit’s technical specifications, plant operating procedures, and NRC 

regulations; 

• reviewing operating data, including data logging and review, to ensure that the unit is 

operating safely; and 

• being able to manually initiate engineered safety features during various transient and 

accident conditions. 

To carry out these and other responsibilities in a timely fashion, the operator at the controls of a 

nuclear power unit must pay attention to the condition of the unit at all times. The operator must be alert 

to ensure that the unit is operating safely and must be able to take action to prevent any progress toward 

an unsafe condition. This is facilitated by control room design and layout in which all controls, 

instrumentation displays, and alarms required for the safe operation, shutdown, and cooldown of the unit 

are readily available to the operator in the control room. 

2. Senior Operator in the Control Room 

A need exists for guidance on acceptable methods of complying with the Commission’s 

requirement in 10 CFR 50.54(m)(2)(iii) that a senior operator must be present in the control room at all 

times when a nuclear power unit is in an operational mode other than cold shutdown or refueling as 

defined by the unit’s technical specifications. A senior operator currently assigned to control room duties 

and within the confines of the control room must be in sight of, or in audible range of, the operator at the 

controls or must be in audible range of the control room annunciators. The technical expertise of both a 

senior operator and a reactor operator is required in the control room because of the differences in their 

training programs and experience. 
Rev. 3 of RG 1.114, Page 3 

The staffing rule requires the continuous presence of a senior operator in the control room to 

ensure the following: 

a. An individual is available who can provide the oversight function of the supervisor and 

improve the probability of correctly detecting abnormal events early enough to mitigate 

potential adverse consequences. 

b. The senior operator in the control room is aware of plant conditions before, and resulting 

from, an abnormal event. This helps ensure that the extra experience, training, and 

knowledge of the senior operator is available to aid in promptly mitigating the event. 

c. The operator at the controls can concentrate on performing the immediate actions 

necessary to mitigate the event rather than having to brief the senior operator about the 

event if the senior operator was absent from the control room when the event occurred. 

C. REGULATORY POSITION 

1. Operator at the Controls 

1.1 The operator at the controls of a nuclear power unit should have an unobstructed view of, and 

access to, the operational control panels, including instrumentation displays and alarms, to initiate 

prompt corrective action when necessary on receipt of any indication (i.e., instrument response or 

alarm) of a changing condition. Operational control panels are control panels that enable the 

operator at the controls to perform required manual safety functions and equipment surveillance 

and to monitor plant conditions under normal and accident conditions. 

1.2 The operator at the controls should not normally leave the area where continuous attention, 

including visual surveillance of annunciators and instrumentation, can be given to reactor 

operating conditions and where the operator has access to the reactor controls. For example, the 

operator should not routinely enter areas behind control panels where he cannot monitor plant 

performance. If the control room design is such that an operator must enter areas behind control 

panels to monitor back panels, either a senior operator or reactor operator assigned to the current 

control room shift must be within view of the control panels during the time that the normally 

assigned operator is monitoring the back panels. The operator at the controls should not, under 

any circumstances, leave the surveillance area (i.e., defined by the administrative procedures 

described in response to Regulatory Position 1.3 below) for any nonemergency reason (e.g., to 

confer with others or for personal reasons) without ensuring that a qualified relief operator is at 

the controls. In an emergency that affects the safety of operations, the operator at the controls 

may momentarily be absent from the defined surveillance area to verify the receipt of an 

annunciator alarm or to initiate corrective action, provided that the operator remains within the 

confines of the control room. 

1.3 Administrative procedures should be established that define and outline (preferably with 

sketches) the specific area within the control room designated as the “surveillance area” where 

the operator at the controls should remain. The procedures should define the surveillance area 

and other areas that the operator at the controls may enter to verify the receipt of an annunciator 

alarm or to initiate corrective action in an emergency that affects the safety of operations. 
Rev. 3 of RG 1.114, Page 4 

1.4 Before assuming responsibility as the operator at the controls, the relief operator should be 

properly briefed on the unit’s status. Administrative procedures should describe what is required 

to ensure the proper transfer of responsibility during the change of shifts or when an operator on 

duty is relieved as operator at the controls during a shift. The procedures should include, as a 

minimum, a definition of proper relief (e.g., what information the operator must pass on to the 

relief operator and that must be acknowledged between the two operators). 

1.5 A single operator should not assume responsibility as the operator at the controls for more than 

one nuclear power unit at the same time. This is one of the minimum requirements in 

10 CFR 50.54(m)(2)(i) for onsite staffing of nuclear power units per shift by licensed operators. 

2. Senior Operator in the Control Room 

2.1 A designated senior operator, as defined in 10 CFR 55.4, should be present in the control room to 

meet the requirements of 10 CFR 50.54(m)(2)(iii). 

2.2 The senior operator in the control room should spend most of the time in that portion of the 

control room where there is direct and prompt access to information on current unit conditions 

and where the senior operator can directly supervise and communicate with the operator or 

operators at the controls. 

2.3 The senior operator should have the flexibility to move periodically for a brief time to other parts 

of the control room, as long as the senior operator is at all times within the control room vital area 

and meets either of the following conditions. 

a. The senior operator can see or hear the reactor operator at the controls. 

b. The senior operator can hear the control room annunciators. 

2.4 Administrative procedures should be established that define and outline (preferably with 

sketches) the specific area within the control room (see Regulatory Position 2.2 above) where the 

senior operator normally should remain while performing designated duties. 

2.5 Before assuming responsibility as the senior operator in the control room, the relief senior 

operator should be properly briefed on the unit’s (or units’) status. Administrative procedures 

should describe what is required to ensure that the proper transfer of responsibilities occurs when 

a senior operator on duty in the control room is relieved of control room responsibility during a 

shift or during a change of shifts. The procedures should include, as a minimum, definitions of 

proper relief (e.g., what information the operator must pass on to the relief operator and that must 

be acknowledged between the two senior operators) and notification to the control room shift 

crew by the senior operator in charge. 

2.6 A single senior operator in the control room should not assume the responsibility for more than 

one control room, but he or she may be responsible for all units operated from a single control 

room. This is one of the minimum requirements in 10 CFR 50.54(m)(2)(i) for onsite staffing of 

nuclear power units per shift by senior operators. 
Rev. 3 of RG 1.114, Page 5 

D. IMPLEMENTATION 

The purpose of this section is to provide information to applicants and licensees regarding the 

NRC’s plans for using this regulatory guide. The NRC does not intend or approve any imposition or 

backfit in connection with its issuance. 

In some cases, applicants or licensees may propose or use a previously established acceptable 

alternative method for complying with specified portions of the NRC’s regulations. Otherwise, the 

methods described in this guide will be used in evaluating compliance with the applicable regulations for 

license applications, license amendment applications, and amendment requests.