ansi-ans- 14.1

ANSI/ANS-14.1-2004

operation of fastpulse reactors

AN

SI/A

NS-1

4.1-

2004

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ANSI/ANS-14.1-2004

American National StandardOperation of Fast

Pulse Reactors

SecretariatAmerican Nuclear Society

Prepared by theAmerican Nuclear SocietyStandards CommitteeWorking Group ANS-14.1

Published by theAmerican Nuclear Society555 North Kensington AvenueLa Grange Park, Illinois 60526 USA

Approved April 23, 2004by theAmerican National Standards Institute, Inc.



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AmericanNationalStandard

Designation of this document as an American National Standard attests thatthe principles of openness and due process have been followed in the approvalprocedure and that a consensus of those directly and materially affected bythe standard has been achieved.

This standard was developed under procedures of the Standards Committee ofthe American Nuclear Society; these procedures are accredited by the Amer-ican National Standards Institute, Inc., as meeting the criteria for AmericanNational Standards. The consensus committee that approved the standardwas balanced to ensure that competent, concerned, and varied interests havehad an opportunity to participate.

An American National Standard is intended to aid industry, consumers, gov-ernmental agencies, and general interest groups. Its use is entirely voluntary.The existence of an American National Standard, in and of itself, does notpreclude anyone from manufacturing, marketing, purchasing, or using prod-ucts, processes, or procedures not conforming to the standard.

By publication of this standard, the American Nuclear Society does not insureanyone utilizing the standard against liability allegedly arising from or afterits use. The content of this standard ref lects acceptable practice at the time ofits approval and publication. Changes, if any, occurring through developmentsin the state of the art, may be considered at the time that the standard issubjected to periodic review. It may be reaffirmed, revised, or withdrawn atany time in accordance with established procedures. Users of this standardare cautioned to determine the validity of copies in their possession and toestablish that they are of the latest issue.

The American Nuclear Society accepts no responsibility for interpretations ofthis standard made by any individual or by any ad hoc group of individuals.Requests for interpretation should be sent to the Standards Department atSociety Headquarters. Action will be taken to provide appropriate response inaccordance with established procedures that ensure consensus on theinterpretation.

Comments on this standard are encouraged and should be sent to SocietyHeadquarters.

Published by

American Nuclear Society555 North Kensington AvenueLa Grange Park, Illinois 60526 USA

Copyright 2004 by American Nuclear Society. All rights reserved.

Any part of this standard may be quoted. Credit lines should read Extracted fromAmerican National Standard ANSI0ANS-14.1-2004 with permission of the publisher,the American Nuclear Society. Reproduction prohibited under copyright conventionunless written permission is granted by the American Nuclear Society.

Printed in the United States of America



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Foreword ~This foreword is not part of American National Standard Operation of Fast PulseReactors, ANSI0ANS-14.1-2004.

Nuclear devices designed and operated for purposes of research and as sources ofsharp, intense pulses of fission-produced radiation have functioned successfullyfor more than 40 years. In the usual operation, superprompt criticality is estab-lished in a mass of unmoderated fissile metal, radiation is produced, and thenuclear reaction is immediately terminated by characteristics inherent in thefissile material itself. These devices have come to be known as fast pulse reac-tors. This standard provides direction in the use of such specialties so that therisk of damage to personnel and equipment can be controlled. It was prepared byindividuals having extensive and intimate experience in the operation of thistype of reactor.

At the time of the initial publication in 1975, the membership of Subcommittee14 was as follows:

A. De La Paz ~Chair!, White Sands Missile Range

L. M. Bonson, Sandia National LaboratoriesK. Elliott, Albuquerque Operations Office, U.S. Atomic Energy CommissionL. P. Holland, Oak Ridge National LaboratoryA. H. Kazi, Aberdeen Pulse Radiation FacilityR. L. Long, University of New MexicoJ. M. Reuscher, Sandia National LaboratoriesT. F. Wimett, Los Alamos Scientific Laboratory

In 2000, a working group was reestablished to review and update the standard.The standard had been reaffirmed in 1982, 1989, and 2000. The standard neededto be updated to ref lect changes in procedures and to reference associatedstandards. The members of Working Group 14.1 producing the revised standardare as follows:

T. R. Schmidt ~Chair!, Sandia National Laboratories

R. E. Anderson, Los Alamos National LaboratoryJ. W. Bryson, Sandia National LaboratoriesM. J. Burger, Sandia National LaboratoriesA. De La Paz, Vista TechnologiesJ. R. Felty, Science Applications International CorporationT. Michael Flanders, White Sands Missile RangeA. H. Kazi ~Retired!, Aberdeen Pulse Radiation FacilityR. A. Knief, XE CorporationR. L. Long, Nuclear Stewardship, LLCM. Mendonca, U.S. Nuclear Regulatory CommissionD. M. Minnema, National Nuclear Security AdministrationG. A. Schlapper, National Nuclear Security Administration

This standard was processed and approved for submittal to ANSI by the Amer-ican Nuclear Societys Research Reactors, Reactor Physics, Radiation Shielding& Computational Methods ~N17! Committee on ANSI0ANS-14.1-2004, Opera-tion of Fast Pulse Reactors. Committee approval of the standard does notnecessarily imply that all committee members voted for its approval. At the timeit approved this standard, the N17 committee had the following members:

T. M. Raby ~Chair!, National Institute of Standards and TechnologyA. Weitzberg ~Vice-Chair!, Scientech, Inc.

R. E. Carter, IndividualD. Cokinos, Brookhaven National LaboratoryB. Dodd, Health Physics SocietyW. A. Holt, American Public Health AssociationW. C. Hopkins, IndividualL. I. Kopp, Individual

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L. B. Marsh, U.S. Nuclear Regulatory Commission~Alt. A. Adams, U.S. Nuclear Regulatory Commission!

J. F. Miller, Institute of Electrical and Electronics Engineers, Inc.J. E. Olhoeft, IndividualW. J. Richards, University of CaliforniaR. Seale, University of ArizonaT. R. Schmidt, Sandia National LaboratoriesA. O. Smetana, Savannah River National LaboratoryE. G. Tourigny, U.S. Department of EnergyD. K. Trubey, IndividualS. H. Weiss, National Institute of Standards and Technology

~Alt. T. J. Myers, National Institute of Standards and Technology!W. L. Whittemore, General Atomics

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Contents Section Page

1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.1 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2 Shall, Should, May . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.3 Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

3 Administrative Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.1 Line Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.2 General Operational Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.3 Experiment Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.4 Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.5 Reactor Operations Staff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.6 Pulse Operations Staff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.7 Maintenance and Experiment Setup Staff . . . . . . . . . . . . . . . . . . . . . . . 23.8 Operations Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.9 Access Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3.10 Emergency Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.11 Radiological Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.12 Annual Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.13 Quality Assurance Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

4 Facility Design Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.1 Reactor Facility Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.2 Physical Barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.3 Public Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.4 Radiation Detection System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.5 Contamination Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.6 Decommissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

5 Reactor Design Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.1 Reactivity Quenching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.2 Safety Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.3 Primary Safety Device Reactivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.4 Interlocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.5 Shroud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.6 Control Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.7 Pulse Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45.8 Pulse Reproducibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

6 Control Design Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.1 Physical Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.2 Manual Scrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.3 Control Element Position Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.4 Loss of Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.5 Measurement Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.6 Personnel Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.7 Reactor Area Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.8 Personnel Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

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7 Operational Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.1 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.2 Reactor Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.3 Reactor Modification0Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.4 Reactivity Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.5 Unexpected Reactor Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.6 Preoperational Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.7 Experiment Inf luence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.8 Equipment Securing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57.9 Initial Critical Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

7.10 Pulse Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

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Operation of Fast Pulse Reactors1 Scope

This standard is for those involved in the de-sign, operation, and review of fast pulse reac-tors. It has been formulated in general termsto be applicable to all current fast pulse reac-tors. This standard does not apply to periodi-cally pulsed reactors or booster assemblies.

2 Definitions

2.1 Limitations

The definitions given below are restrictive forthe purposes of this standard. Other special-ized terms are defined in the Glossary of Termsin Nuclear Science and Technology, @1#1! or havedefinitions accepted by usage.

2.2 Shall, should, may

The word shall is used to denote a require-ment; the word should is used to denote arecommendation; and the word may is usedto denote permission, neither a requirementnor a recommendation. To conform with thisstandard, all operations shall be performed inaccordance with its requirements, but not nec-essarily with its recommendations.

2.3 Glossary of terms

control elements: Those reactor fuel or neu-tron ref lection components whose movementincreases or decreases the reactivity of the re-actor. Included are control rods, pulse rod, safetyblock, and ref lectors or equivalent.

fast pulse reactor (also referred to as fastburst reactor): An essentially unmoderatedassembly of fissionable material designed toproduce short-duration, high-intensity pulsesof fission radiation. Also, it may be operated ata steady-state power level.

interlock: A switch, relay, or hardware0softwarecombination that locks in a priority of eventsor that locks out a particular event.

neutron decay interval: The interval of timein the pulse production cycle of the reactor dur-ing which a subcritical configuration is at-tained to allow for decay of delayed neutronprecursors.

reactor area: A region in the vicinity of thereactor where personnel shall not be presentduring a reactor operation.

reactor operating staff: Those personnel, in-cluding reactor supervisor and reactor operatorpersonnel, certified in accordance with proce-dures established by management to carry outoperation of the reactor.

reactor operator: An individual certified tomanipulate the controls of a reactor.

reactor shutdown: The condition where, as aminimum, the safety block or equivalent is inits minimum reactivity position.

reactor supervisor: See senior reactor operator.

safety block: The control element having areactivity worth such that its movement is theprimary mechanical means of shutting downthe operation.

safety device: A mechanism or system de-signed to move a control element to reduce thereactivity of a fast pulse reactor.

scram: The act of shutting down a reactor sud-denly by operation of the reactor safety devices.

senior reactor operator: An individual certi-fied to direct the activities of reactor operators.Such an individual is also a reactor operator.

3 Administrative practices

3.1 Line organization

Management shall assign responsibility andcommensurate authority for safe operation ofthe reactor unambiguously and singularlythrough the line organization.

1!Numbers in brackets refer to corresponding numbers in Section 8, References.

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3.2 General operational restrictions

Written general operational restrictions for thereactor, based on a safety assessment and con-sideration of characteristics including shieldingand confinement, shall be approved by manage-ment and the cognizant regulating authority. Cri-teria for the safety assessment may be derivedfrom the American National Standard Formatand Content for Safety Analysis Reports for Re-search Reactors,ANSI0ANS-15.21-1996 @2#. Cri-teria for operational restrictions may be derivedfrom the American National Standard The De-velopment of Technical Specifications for Re-search Reactors, ANSI0ANS-15.1-1990 @3# .

3.3 Experiment plan

Prior to the start of each experiment, an ex-periment plan shall be reviewed and approvedin accordance with procedures approved bymanagement.

3.4 Training

Reactor operating staff personnel shall betrained to ensure that they are capable of per-forming their assigned work. Continuing train-ing, including periodic reactor operations, shallbe provided to ensure that job proficiency ismaintained. Criteria for personnel qualifica-tions and training may be derived from theAmerican National Standard Selection andTraining of Personnel for Research Reactors,ANSI0ANS-15.4-1988 @4# .

3.5 Reactor operations staff

At least two members of the reactor operatingstaff, one of whom is a reactor supervisor, shallbe present in the reactor facility during opera-tion of the reactor, and one of the two shall bepresent at the control console at all times dur-ing operation of the reactor.

3.6 Pulse operations staff

At least two members of the reactor operatingstaff, one of whom is a reactor supervisor, shallbe present at the reactor control console areaduring pulse rod calibrations, pulse setup, andconduct of the pulse.

3.7 Maintenance and experiment setupstaff

A minimum of two individuals, at least one ofwhom is a member of the reactor operating

staff, shall be present during reactor mainte-nance or experimental setup operations involv-ing access to the reactor. A member of theoperating staff shall be present at the reactorcontrol console while power is provided for move-ment of the control elements. Such mainte-nance or experimental setup operations shallbe approved by a reactor supervisor.

3.8 Operations procedures

Written procedures shall be used for all reactoroperations. Provision shall be made for keepingprocedures current and in compliance with op-erational restrictions.

3.9 Access procedures

Written procedures shall be established for con-trol of access to the reactor area.

3.10 Emergency plan

An emergency plan approved by managementshall be in effect, and emergency equipmentshall be provided. Criteria for an emergencyplan may be derived from the American Na-tional Standard Emergency Planning for Re-search Reactors, ANSI0ANS-15.16-1982 @5# .

3.11 Radiological protection

Radiation monitoring, personnel dosimetry, andcontamination control shall be provided for bothnormal and emergency conditions. Criteria fora radiation protection program may be derivedfrom the American National Standard Radia-tion Protection at Research Reactor Facilities,ANSI0ANS-15.11-1993 @6# .

3.12 Annual review

Knowledgeable personnel, independent of thereactor operating staff, shall review the reac-tors administrative, operational, and safetypractices at least annually. The results of thereview shall be documented.

3.13 Quality assurance plan

Design of the facility, reactor, and control sys-tem, and modifications thereto, shall adhereto a quality assurance plan approved by man-agement. Criteria for a quality assurance planmay be derived from the American NationalStandard Quality Assurance Program Require-ments for Research Reactors, ANSI0ANS-15.8-1995 @7# .

American National Standard ANSI0ANS-14.1-2004



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4 Facility design criteria

4.1 Reactor facility planning

The following shall be considered in planning afast pulse reactor facility:

~1! prevention of accidental criticality or re-activity increases that might result from cred-ible malfunctions;

~2! control of entry into hazardous areas;

~3! convenience, feasibility, and ease of reac-tor system maintenance commensurate withanticipated radiation levels;

~4! prevention of f looding of the reactor;

~5! implementation of emergency response;

~6! limiting neutron activation by using ap-propriate construction materials.

4.2 Physical barriers

Physical barriers shall be provided for protec-tion of operating staff and experimenters fromradiation associated with normal reactor oper-ations and credible accidents.

4.3 Public protection

Provision ~e.g., shielding, fencing, and dis-tance! shall be made for protection of the pub-lic from radiation associated with normal reactoroperations and from credible accidents.

4.4 Radiation detection system

A permanently installed radiation detection sys-tem shall be provided to monitor and indicatethe radiation levels, with appropriate alarms,at selected points throughout the facility.

4.5 Contamination monitoring

Means shall be provided for contamination mon-itoring of personnel exiting the reactor area.

4.6 Decommissioning

Consideration should be given to decommission-ing of the facility during the design phase. Cri-teria for decontamination and decommissioningmay be derived from the American NationalStandard Decommissioning of Research Reac-tors, ANSI0ANS-15.10-1994 @8# .

5 Reactor design criteria

5.1 Reactivity quenching

Inherent prompt reactivity quenching ~e.g., neg-ative temperature coefficient! shall be a funda-mental characteristic of the reactor.

5.2 Safety devices

At least two independent safety devices ~suchas safety block and control elements! shall beprovided. The safety devices shall be fail-safewith respect to loss of electrical power.

5.3 Primary safety device reactivity

The primary safety device ~such as safety blockmovement! shall be capable of shutting downthe reactor under conditions corresponding tothe most reactive experiment arrangement.

5.4 Interlocks

Interlocks shall be provided to prevent

~1! reset of the control system for subsequentoperation of the reactor unless the controlelements are at positions of minimum reac-tivity worth;

~2! insertion of the safety block unless theother control elements are at positions of min-imum reactivity worth, except at the end ofthe neutron decay interval;

~3! insertion of two different types of controlelements simultaneously;

~4! positive reactivity insertion by control ele-ments during the neutron decay interval;

~5! personnel access to the reactor area dur-ing operation.

5.5 Shroud

A shroud to limit the effects of neutron ref lec-tion by experiments should be available andused as deemed appropriate after review of pro-posed experiments.

5.6 Control elements

Control elements shall be provided having areactivity worth sufficient to shut down thereactor with the most reactive experiment ar-rangement, and the most reactive control ele-ment in its most positive reactive position.




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5.7 Pulse element

The pulse element should be designed so thatit reaches its maximum reactivity value at thelimit of its travel.

5.8 Pulse reproducibility

Reproducibility of the effect of the control com-ponents should be such that pulse yield varia-tion is controlled ~typically will not exceed 110%of the expected value!.

6 Control design criteria

6.1 Physical controls

Physical controls shall be provided to pre-vent operation of the reactor by unauthorizedpersonnel.

6.2 Manual scrams

Provisions for manual scram actuation shallexist at the reactor control console and in thosegeneral locations in the reactor area that re-quire the exclusion of personnel prior to reac-tor operation.

6.3 Control element position indicators

Indications of control element positions shallbe provided at the control console.

6.4 Loss of power

Loss of power to any safety device shall initiatea scram.

6.5 Measurement channels

A minimum of two neutron f lux ~power! mea-surement channels and two fuel temperaturemeasurement channels shall be provided; atleast one of each type shall be operating whenthe reactor is not shut down.

6.6 Personnel warning

Automatic means shall be provided to warnpersonnel in and near the reactor area that thereactor is about to be operated.

6.7 Reactor area monitoring

Monitoring of the reactor area by visual and au-dible means should be provided, such as closed-circuit television and intercom from the console.

6.8 Personnel communications

Means of communication shall be provided be-tween personnel at the reactor control consoleand others in the reactor area.

7 Operational practices

7.1 Quality assurance

Formal programs for conduct of operations andquality assurance shall be implemented. Crite-ria for conduct of operations and quality assur-ance may be derived from the American NationalStandard Quality Assurance Program Require-ments for Research Reactors, ANSI0 ANS-15.8-1995 @7# .

7.2 Reactor area

Procedures for ensuring that the reactor areais cleared of all personnel shall be completedprior to the start of each reactor operation.

7.3 Reactor modification/maintenance

Operability of the required reactor systems orsafety devices shall be verified before resump-tion of routine operations following installa-tion, modification, or maintenance.

7.4 Reactivity monitoring

The effects of reactivity changes shall be ob-served and be consistent with reactor operat-ing staff expectations. Unless a scram iswarranted, deviations shall be evaluated be-fore proceeding further.

7.5 Unexpected reactor behavior

Any unexpected behavior of the reactor or itsassociated equipment shall be evaluated. Thereactor shall be placed in a safe condition, androutine operations shall be suspended until thecause of the unexpected behavior has beeninvestigated.

7.6 Preoperational checks

Operability of the required number of safetydevices and monitoring systems shall be estab-lished prior to starting operations each day.

7.7 Experiment influence

Consideration of the inf luence of an experi-ment on reactivity and the calibration of con-trol elements shall be guided by prior experimentinformation or calculation, or both.




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7.8 Equipment securing

Equipment shall be secured to prevent inadver-tent movement of an experiment, or its compo-nents, during the pulse sequence or the pulseitself.

7.9 Initial critical operations

The following tasks shall be performed as partof the initial critical operation conducted fol-lowing the first assembly of the reactor fuel atthe facility site. These tasks shall be conductedin accordance with formally approved writtenprocedures:

~1! verification that the facility and reactordesign criteria have been met ~e.g., shieldingeffectiveness, inherent prompt reactivityquenching!;

~2! visual and mechanical check of the reac-tor fuel assembly;

~3! determination of the rate of shutdownassociated with safety block movement;

~4! detailed calibration of the control ele-ments including a check of the reproducibil-ity of the reactivity effects of cycling thecontrol elements;

~5! calibration of the pulse element with suf-ficient detail to govern adjustment to thedesired worth, as applicable;

~6! calibration of the instrumentation usedto make incremental reactivity adjustmentssuch as those required to compensate for re-activity effects of peripheral experimentalequipment;

~7! calibration of channels required for oper-ations ~e.g., temperature, neutron!;

~8! Items 7.9~2! through 7.9~7! above shouldbe performed at least annually.

7.10 Pulse production

The pulse production cycle shall consist of

~1! a reference reactivity check at delayedcritical or by means of a controlled positiveperiod;

~2! adjustment of the control and0or pulse ele-ment positions, taking into account the reac-tor fuel temperature and the effects of theexperimental arrangement on the reactivityworth of the pulse element so that actuation

of the pulse element will give the desired re-activity. This latter adjustment may be part ofa procedure to determine the reactivity worthof the pulse element using a subprompt criti-cal positive period measurement;

~3! removal of reactivity to start the neutrondecay interval for reducing the neutron pop-ulation in the core;

~4! small adjustment in reactivity by controlelement movement to compensate for a tem-perature variation during the neutron decayinterval if required;

~5! readdition of the reactivity removed instep 7.10~3!;

~6! activation of the pulse element followedby automatic scram;

~7! a check to ensure that all control ele-ments have reverted to safe shutdowncondition.

8 References

@1# H. ALTER and ANS STANDARDS SUB-COMMITTEE ON NUCLEAR TERMINOL-OGY AND UNITS ~ANS-9!, Glossary ofTerms in Nuclear Science and Technology,American Nuclear Society, La Grange Park,Illinois ~1986!.

@2# American National Standard, Format andContent for Safety Analysis Reports forResearch Reactors, ANSI0ANS-15.21-1996,American Nuclear Society, La Grange Park,Illinois.

@3# American National Standard, The Devel-opment of Technical Specifications for Re-search Reactors, ANSI0ANS-15.1-1990;R1999, American Nuclear Society, LaGrange Park, Illinois.

@4# American National Standard, Selection andTraining of Personnel for Research Reac-tors, ANSI0ANS-15.4-1988; R1999, Amer-ican Nuclear Society, La Grange Park,Illinois.

@5# American National Standard, EmergencyPlanning for Research Reactors, ANSI0ANS-15.16-1982; R2000, American Nu-clear Society, La Grange Park, Illinois.




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@6# American National Standard, RadiationProtection at Research Reactor Facilities,ANSI0ANS-15.11-1993; R2004, AmericanNuclear Society, La Grange Park, Illinois.

@7# American National Standard, Quality As-surance Program Requirements for Re-search Reactors, ANSI0ANS-15.8-1995,American Nuclear Society, La Grange Park,Illinois.

@8# American National Standard, Decommis-sioning of Research Reactors, ANSI0ANS-15.10-1994, American Nuclear Society, LaGrange Park, Illinois.

NOTE: When any American National Standardreferred to in this document is superseded by arevision approved by the American NationalStandards Institute, Inc., the revision shallapply.




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