ML20154S157

Proposed Rule 10CFR76, Regulation of U Enrichment Facilities. Rule Would Provide Procedures for Safe Handling of UF6

ML20154S157
Person / Time
Site:	Westinghouse
Issue date:	04/18/1988
From:	Chilk S NRC OFFICE OF THE SECRETARY (SECY)
To:
Shared Package
ML20154R836	List: ML20154R832 ML20154S157
References
RULE-PR-76-MISC PR-880418, NUDOCS 8806080400
Download: ML20154S157 (27)

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[7590-01]

NUCLEAR REGULATORY COMMISSION Proposed 10 CFR Part 76 Regulation of Uranium Enrichment Facilities AGENCY: Nuclear Regulatory Comission.

ACTION: Advance notice of proposed rulemaking.

SUMMARY

The Nuclear Regulatory Comission (NRC) is considering the addition of new regulations Title 10 (Part 76) for uranium enrichment facilities. The construction and operation of such facilities currently would be licensed pursuant to the Comission's regulations in 10 CFR Part 50 for other production and utilization facilities, such as nuclear power plants. In this notice, the Commission presents its current analy-sis of the applicabi'iity of the existing regulations, in 10 CFR Part 50, to uranium enrichment facilities and poses questions for the purpose of eliciting comments on whether a separate set of regulations for uranium enrichment licensing is desirable.

The General Design Criteria presented in this notice may be proposed for codification in the new regulation. These criteria may also be modi-fied, depending on comments received in response to this notice, and upon further staff analysis.

DATES: The comment period expires on July 21, 1988 . Comments received after this date will be considered if it is practical to do so, but assurance of consideration cannot be given except as to comments received on or before this date.

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ADDRESSES: Mail comments to: The Secretary of the Commission, U.S.

Nuclear Regulatory Commission, Washington, DC 20555, Attention: Docket-ing and Service Branch.

Deliver comments to: 11555 Rockville Pike (One White Flint North) Rockville, MD, between 7:30 a.m. and 4:15 p.m. Examine copies of comments received at: the NRC Public Document Room, 1717 H Street NW.,

Washington, DC.

FOR FURTHER INFORMATION CONTACT: A. Thomas Clark, Jr. , Of fice of Nuclear Material Safety and Safeguards, U.S. Nuclear Regulatory Commission, Washington, DC 20555, telephone (301)492-0697.

SUPPLEMENTARY INFORMATION:

Background

A uranium enrichment facility is a production facility as defined by Section 11(v) of the Atomic Energy Act of 1954, as amended. The regula-tions which currently govern the Commission's review and evaluation of an applicatior. for a production facility are contaii'.ed in 10 CFR Part 50.

Part 50 provides no specific guidance for licensing uranium enrichment facilities. The NRC staff has never received an application for a uranium enrichment facility. The staff, however, has licensed facilities which process uranium hexafluoride, which is the principal chemical form of mniw used in the gaseous diffusion process and the centrifuge process, the u rrent methods used to produce enriched uranium.

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However, other methods for enriching uranium can be and are being developed. For example, for several years the Department of Energy has fostered the development of an Atomic Vapor Laser Isotope Separation (AVLIS) process for enriching uranium. The commercial use of these methods would also be subject to regulation by the Commission.

On April 7,1986, the Department of Energy (the Department or DOE) published a notice in the Federal Register (51 FR 11811) requesting expressions of interest for participation in the Department's uranium enrichment program. In addition, on February 17, 1987, the Department submitted a report to the Congress on the privatization of DOE's uranium enrichment enterprise. The report was prepared in response to issues raised in Conference Report H.R. 99-1005 (House Joint Resolution 738 Continuing Appropriation, 1987). The letter transmitting the report indi-cated that a core specific recommendation would be made by the Department at the end of March on the restructuring of the enrichment enterprise.

On March 31, 1987, the Department provided further details on the proposed restructuring. The principal component of the restructuring would be a federally chartered enrichnent corporation, which might be subject to regulation by the U.S. Nuclear Regulato.y Commission. The NRC staff has also been meeting with some private companies, all of which are expressing an interest in engaging in uranium enrichment under NRC license and r.9gul ation.

This advance notice of proposed rulemaking is being published to provide the public, the Department, and the prospective regulated industry an opportunity to provide advice and recommendations to the Commission on the subject of uranium enrichment licensing. The NRC staff has developed guidance, provided below, which would form the foundation for a new rule, 3

if initiated. Because rulemaking may take several years, and applications for private enrichment might be imminent, the NRC staff will proceed with the review of applications and issuance of appropriate licenses and permits, on the basis of the current regulations in 10 CFR Part 50 and the guidelines contained in this advance notice subject to any revisions which might be appropriate based on comments received.

As noted above, current regulations already provide a framework for the licensing review of production facilities. The initiation of a rulemak-ing to more closely define the substance of NRC review should not hold up the processing to completion of submitted applications.

Uranium Hexafluoride and Public Health and Safety of Uranium Enrichment Although the regulation of uranium enrichment facilities could include any type of technically feasible enrichment process, as a pract-ical matter the two predominant techniques, gaseous diffusion snd gaseous centrifugation, enrich the uranium utilizing the chemical form of uranium hexafluoride. The principal reason for using this form is that the com-pound is a gas at reasonable temperatures and pressures. The release of uranium hexafluoride from process equipment is a more severe chemical (toxicological) hazard than a radiation (radiological) hazard as dis-cussed below.

If uranium hexafluoride is released to the atmosphere it will react exothermally with moisture in the air to produce hydrogen fluoride (HF) and uranyl fluoride (U02 F2 ). Both compounds can be toxic. Hydrogen fluoride is a corrosive acid vapor which can severely damage tissue, i

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especially the moist tissue of the lungs if inhaled in sufficient con-centrations. If uranyl fluoride is inhaled or ingested, it can cause internal injury to the kidneys and sufficient quantities can be lethal.

In order to demonstrate that the chemical hazard of uranium hexa-fluoride reaction products far exceeds that of its radiation hazard one might consider the following example related to just one of the reaction products, uranyl fluoride. If a person inhaled sufficient uranyl fluoride, as a result of being exposed to a plume from released uranium hexafluoride (enriched to six percent U-235), such that there was a 50/50 chance of surviving (50 percent lethality) the chemically toxic effects, that person would receive only about 2.5 rem committed (lifetime) total body dose equivalent or about the maximum amount a radiation worker can receive in one calendar quarter (3 rem). Obviously, even further chem-ical injury could be sustained by the same individual from the hydrogen fluoride produced during the same release of uranium hexafluoride.

Design Guidance Standards Based on Chemical Effects Based on the above discussion the staff will be guided mainly by the cheraical effects of reaction products from uranium hexafluoride in its outlook on design for the protection of the health and safety of the public. The Atomic Energy Act provides authority for the Commission to consider any consequence to the public health and safety inherent in the physical characteristics of licensed source or special nuclear material 5

such as uranium hexafluoride. The staff herein proposes reference values to be used for the evaluation of sites and designs with respect to potential accidents at uranium enrichment facilities. These proposed reference values for UO2 F2 and HF, based on chemical toxicity, are intended to be comparable with the original intent of tne reactor siting criteria in 10 CFR Part 100, i.e. , a whole-body radiation dose guideline value fixed at the point where it is believed th:t clinicclly obsGrvable thr65h01d effects begin to occur. The staff thus proposes using quantities or concentration values which are at the lower range or average threshold level for chemically toxic effects which, if exceeded, could cause transient or permanent injury.

The staff considers that an intake of about 9 mg of uranium is the level at which slight transient kidney injury is expected to occur, and an intake of about 40 mg of uranium is a reasonable estimate of the threshold level at which permanent kidney damage may begin to occur (see 1

NUREG-1140). Therefore, for design purposes the staff is considering the calculated maximum amount that an adult at or beyond the controlled site boundary could inhale, as a result of credible accidents of low probabil-ity to be in the range of 9 to 40 mg. Facilities designed such that maximum effects would not exceed this range should not have a significant adverse effect on the health and safety of the public.

1 Copies of NUREG-1140 may be purchased from the Superintendent of Documents, U.S. Government Printing Office, P. O. Box 37082, Washington, DC 20013-7082. Copies are also available from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161. A copy is also available for public inspection and/or copying at the NRC Public Document Room, 1717 H St., NW., Washir.gton, DC.

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For exposure to HF, levels which cause permanent injury are not clearly defined. Exposure to HF at a concentration of 100 mg/m3 is esti-mated to be unbearable for one minute. HF at 13 mg/m3 would be detect-able by smell and cause possible irritation. Above 26 mg/m3 , HF would cause irritation and possible health effects. Therefore, the staff considers that 26 mg/m3 HF is the maximum concentration that a person at or beyond the controlled site boundary could be exposed for short periods, as a result of credible incidents of low probability. Enrich-ment facilities designed to limit any release to a value below this reference concentration will not have a significant adverse effect on the health and safety of the public.

2Just, R.A., "Report on Toxicological Studies Concerning Exposurcs to UFs and UFs Hydrolysis Products," KID-5573, Rev. 1, July 1984.

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Analysis of the Applicability of 10 CFR Part 50 to Uranium Enrichment The NRC staff has reviewed each section of 10 CFR Part 50 to deter-mine which sections do not apply, which sections will apply, including the nature of their applicability, and those which will apply in part.

This analysis is based on the staff's judgment as to technical and proce-dural applicability. The analysis is intended to form a basis for the NRC staff's approach to licensing of uranium enrichment facilities.

A. Those Sections of 10 CFR Part 50 Which Do Not Apply

1. Sections and appendices related only to nuclear reactor licensing:

Sections 50.34a, 50.36a, 50.43, 50.44, 50.46, 50.47, 50.48, 50.49, 50,55a, 50.60, 50.61, 50.62, 50.64, 50.72, 50.73, and 50.109.

Appendices A, C, E, G, H, I, J, K, L, M, N, 0, Q, and R.

2. Sections not applicable for reasons other than 1:

Section Reason 50.11 Exemptions for Federal agencies 50.21 Research and development only Appendix 0 Reserved Appendix F Reprocessing only Appendix P Reserved 8

B. Those Sections of 10 CFR Part 50 Which Apply Completely

1. Sections related to administrative procedures:

Section 50.1 through 50.10, 50.12, 50.13, 50.20 through 50.32, 50.36b, 50.37 through 50.40, 50.41, 50.42, 50.45, 50.50 through 50.53, 50.56, 50.58, 50.59, 50.70, 50.78, 50.80 through 50.110 except 50.109.

2. Appendix B.

C. Those Sections of 10 CFR Part 50 Which Apply Partially

1. Paragraphs (g) and (i) of Section 50.33 do not apply; all other paragraphs apply.

2. Section 50.33a refers to information .equested by the Attorney General for antitrust review. Paragraph (c) is reserved. Paragraphs (a),

l (b), and (d) apply only to nuclear power reactors. Paragraph (e) applies to a uranium enrichment application.

3. Section 50.34, "Contents of Applications; technical information,"

applies in part to a uranium enrichment plant. The extent to which para-graphs of Section 50.34 apply is discussed below:

A. Paragraph (a), Preliminary Safety Analysis Report

! The following paragraphs pertain principally to nuclear power plants: (1), (3)(i), (4), (10), and (11), Replace-ment paragraphs related directly to the intent of these paragraphs should be prepared unless they are only appli-cable to nuclee power plants.

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B. Paragraph (b), Final Safety Analysis Report The following paragraphs pertain principally to nuclear power plants: (1),(2)(i),(4),(6)(v),(6)(vii),and (9). Replacement paragraphs related directly to the intent of these paragraphs should be prepared unless they are only applicable to r.uclear power plants.

C. paragraph (c), Physical Security Plan This paragraph applies in its entirety.

D. Paragraph (d), Safeguards Contingency Plan This paragraph applies in its entirety.

E. Paragraph (e) applies in its entirety.

F. Paragraph (f) does not apply.

G. Paragraph (g) does not apply.

4. Section 50.35 applies, except for paragraph (a)(4)(ii), which refers to nuclear power reactor siting criteria. A replacement paragraph related to siting criteria for a uranium enrichment facility should be prepared.

5. Section 50.36 applies in part to uranium enrichment. The following paragraphs related to nuclear power plants will not apply:

(c)(1)(1)(A) and (c)(1)(ii)(A). Paragraphs (c)(1)(1)(B) and (c)(1)(ii)(B) apply to fuel reprocessing plants, but could equally as well apply to uranium enrichment plants. Paragraph (c)(2) applies to both nuclear power plants and reprocessing plants. This paragraph could 10

apply to uranium enrichment plants in the same manner as it applies to fuel reprocessing plants. All other paragraphs apply to uranium enrich-ment except (c)(7), which is specific to nuclear power plants.

6. Section 50.54, "Conditions of Licenses," applies in part to uranium enrichment. Paragraph (a) applies to nuclear power plants and fuel reprocessing plants, but could be applied to a uranium enrichment plant. The following paragraphs apply to a uranium enrichment plant in their entirety: (b),(c),(d),(e),(f),(g),(h),(i),(1),(n),

(P), (v), (x), (y), (aa) and (cc). The following paragraphs apply only to nuclear power plants: (j),(m),(o),(q),(r),(s), (t),(u),(w),

(z), and (bb). Paragraphs (1-1) and (k) apply to operator licensing and may or may not be applicable to uranium enrichment.

7. Section 50.55, "Conditions of construction permits," applies in part to uranium enrichment. The following paragraphs apply in their entirety to uranium enrichment: (a), (b), (c), and (d). Paragraph (e) applies only to nuclear power plants. Paragraph (f) applies to both nuclear power plants and fuel reprocessing plants (quality assurance) and could apply to a uranium enrichment plant.

8. Section 50.57, "Issuance of operating license," applies in part to uranium enrichment. Paragraphs (a) and (b) apply wholly. Paragraph (c) applies only to nuclear power plants.

9. Section 50.71, "Maintenance of records, making of reports,"

Paragraphs (a) through (d) apply wholly. Paragraph (e) applies to nuclear power plants, but could apply to a uranium enrichment plant.

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Existing Regulatory Basis for Applying Safeguards to Enrichment Facilities

1. Section 50.34(c) requires that each applicant for a license to operate a production or utilization facility must include a physical security plan as part of their application.

2. Section 50.78 requires each holder of a construction permit (issued under Par' 50), if requested by the Commission, to submit installation information on Form N-71, permit verification thereof by the International Atomic Energy Agency, and take such other action as may be necessary to implement the US/IAEA Safeguards Agreement, in the manner set forth in Sections 75.6 and 75.11 through 75.14.

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3. Section 73.1(b)(1)(i) states that Part 73 prescribes require-ments for the physical protection of production and utilization facil-ities licensed pursuant to Part 50.

4. The material control and accountability requirements of Sec-tion 70.51(b)(1), (2), (5), and (6), Sections 70.51(c) and 70.51(d) pertain to enrichment facilities.

5. The Material Control and Accountability Reform Rule, as con-tained in Sections 74.51, 74.53, 74.55, 74.57, and 74.59, pertains to facilities authorized to possess five formula kilograms (or more) of strategic special nuclear material, except for reprocessing plants and nuclear reactors licensed pursuant to Part 50. Thus, this rule would apply to an enrichment facility that handles or produces high enriched uranium (but not those limited to low enriched uranium production).

6. Sections 70.51, 70.57, and 70.58 (in their entirety) pertain to any facility authorized to possess special nuclear material to moderste 12

strategic significance, except that nuclear reactors licensed pursuant to Part 50 are exempted from Sections 70.57 and 70.58. Thus, an enrich-ment facility that handles or produces. uranium enriched above 10 percent but less than 20 percent (in the U-235 isotope) would be subject to Sections 70.51, 70.57, and 70.58.

Existing Safeguards Regulations that do not Apply to Enrichment Facilities but could be Applied either by a Condition of License or by Amending 10 CFR Part 74

1. Section 74.31 (i.e., the Low Enriched Uranium Reform Rule) contains material contro and accountability (MC&A) regulations for facilities authorized to possess special nuclear material of low strategic significance, but specifically exempts production and utiliza-tion facilities licensed pursuant to Part 50.

Oraft General Design Criteria for Uranium Enrichment The staff has prepared draft General Design Criteria for uranium enrichment which are intended to apply to any technique used for that purpose. These draft General Design Criteria have been drawn from several sources, including those previously proposed for other types of

fuel cycle facilities and those in use in 10 CFR Part 50 for nuclear power plants. They are intended to provide general guidance as to j topics which must be considered and the overall performance objectives

! related to each criterion. The actual implementation of the general i

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design criteria will be different than in the case of nuclear power plants and will depend upon the specific processes and designs being considered and will be commensurate with the safety function of the specific structures, systems or components related to those designs.

As experience is gained on the application of the criteria, modifica-tions may be deemed approptiate to the criteria. It is also expected that designs to implement the criteria will in most instances not be comparable with that of nuclear power plants. In particular, the confinement criteria might apply to only limited areas of the plant where significant releases could occur which, in turn, could cause exposure in excess of the reference values for toxic effects.

As discussed in a previous section of this notice, the current technologies, using the chemical form uranium hexafluoride, would be of more immediate concern. In this section we provide these draft criteria as based on the NRC staff's current considerations as to potential hazard to the health and safety of the public. We note, in particular, that the draft criteria presented for design for effects of natural phenomena are characterized by return periods. These criteria should be used in conjunction with data provided by competent authorities which relate design variables such as ground acceleration and wind speed to return period.

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General Design Criteria An application for a construction permit for a uranium enrichment facility must include the principal design criteria for the proposed facility. These General Design Criteria estab-lish minimum requirements for the principal design criteria which are commensurate with their safety function. These General Design Criteria may not be complete. Any omissions do not relieve the applicant from the requirement of providing the necessary safaty features in the design of a specific facility.

In addition to satisfying the General Design Criteria, the applicant must:

(1) Design against the loss of confinement capability or other capability which would jeopardize the health and safety of the public where such loss of capability results from any single failure in systems having safety significance; (2) Provide diversity in systems commensurate with their safety function; (3) Minimize the possibility of non-random, concurrent .

failures of important elements in protection systems; (4) Provide design criteria and design bases for resistance of parts of the facility to upper limit accidents and for maximum probable natural phenomena when the conse-quences of such events endanger the health and safety of the public; (5) Provide adequate protection for employees from hazards which could affect their performance of actions required to pro-tect the public from exposure to hazardous materials.

There may be some facilities for which the General Design Criteria are not sufficient and for which additional criteria must be satisfied in the interest of public safety. Also some of the General Design Criteria may not be necessary or appro-priate for a specific facility. For facilities such as these, departures from the General Design Criteria must be identified and justified.

GENERAL REQUIREMENTS Quality standards and records.

Structures, systems, and components which are determined to have safety significance shall be designed, fabricated, erected, and tested in accordance with the quality assurance criteria set forth in Appendix B to 10 CFR Part 50. Appropriate records of the design, fabrication, erection, and testing of structures, systems, and components which are determined to have safety signficance must be maintained by or under the control of the licensee throughout the life of the facility.

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Protection against environmental conditions.

(a) Structures, systems, and components which are determined to have safety significance shall be designed to withstand the effects of, and be compatible with, the environmental conditions associated with operation, maintenance, shutdown, testing, and accidents.

(b) Structures, systems, and components which are determined to have safety significance shall be protected against dynamic effects, including effects of missiles and discharging fluids, that may result from natural phenomena, accidents at nearby industrial, military, or transportation facilities, equipment failure, and other similar events and conditions both inside and outside the facility.

Protection against fires and explosions.

Structures, systems, and components which are deb nineci to have safety significance must be designed and located so that they can continue to perform their safety functions effectively under credible fire and explosion exposure conditions. Non-combustible and heat resistant materials must be used wherever practical throughout the facility, particularly in locations vital to the control of hazardous materials and to the main-tenance of safety control functions. Explosion and fire detection, alarm, and suppression systems shall be designed and provided with sufficsent capacity and capability to minimize tne adverse effects of fires and explosion on structures, systems, and components which are determined to have safety significance. The design must include provisions to protect against adverse effects that might result from either the operation or the failure of the fire suppression system.

Sharing of structures, systems, and components.

Structures, systems, and components which are determined to have safety significance must not be shared between an enrichment facility and other facilities unless it is shown that such sharing will not impair the capability of the enrichment facility to perform its safety functions, including the ability to return to a safe condition in the event of an accident.

Proximity of sites.

An enrichment facility located near other nuclear facil-ities must be designed to ensure that the cumulative effects of their combined operations will not constitute an j unreasonable risk to the health and safety of the public.

Testing and maintenance of systems and components.

Systems and components that are determined to have safety significance must be designed to permit inspection, maintenance, and testing.

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Emergency capability.

Structures, systems, and components which are determined to have safety significance must be designed for emergencies.

The design must provide for accessibility to the equipment of onsite and available offsite emergency facilities and services such as hospitals, fire and police departments, ambulance service, and other emergency agencies.

DESIGN BASIS FOR NORMAL OPERATION, FOR ACCIDENTS, AND FOR PROTECTION AGAINST NATURAL PHENOMENA Desian.

(a) Enrichment facilities must be designed so that the concentration of hazardous materials at or beyond the boundary of the exclusion area (1) under normal operating conditions, shall be as low as is reasonably achievable, and (2) as the result of design basis accidents including those of low probability, shall not create any undue risk to the health and safety of the public.

(b) The design of the facility must be adequate to provide protection against severe external events that could result in the release of quantities and concentrations of hazardous material which may be of public health and safety significance. The design bases for such events shall take into account their historic frequency and severity in the region of the site and the potential risk to public health and safety, including the inventory of hazardous materials in the facility and the size and the prox'.mity of the population at risk. The type of severe events to t.e considered will vary among sites, however, earthquakes, tornadoes, and floods shall be considered in all cases, as described in paragraphs c, d, and e below.

(c) Historical information concerning the regional seismicity interpreted in light of regional structural geology and site geological conditions shall be used for determining the maximum vibratory ground motion which reasonably could be expected to affect the site during the operatirig life of the facility. Such an earthquake will have a mean return period of the order of 500 years.3 Design earthquakes of shorter return period may be proposed, and shall be justified through considera-tions of the incremental risk to public health and safety relative to the 500 year interval.

3 The return period should be related to vibratory ground motion through the use of seismic risk maps such as Figure CI-2 of "Tentative Provisions for the Development of Seismic Regula-tions for Buildings," Applied Technology Council, ATC 3-06, U.S. Department of Commerce-National Bureau of Standards Special Publication 510, National Science Foundat. ion Publication 78-8. (An update of this map is expected soon.) '

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(d) Historical information concerning the regional and I local incidence and severity of tornadoes shall be used to l establish a site-specific design tenado event. The character-istics of the design tornado shall be determined considering both the tornado frequency for the region in which the facility is located, as well as the frequency of occurrence for a tornado of a given intensity within that region.4 (e) The design basis flood as a minimum shall be the Standard Project Flood as defined and in common use by the Corps of Engineers. The Standard Project Flood is the flood resulting from the most severe flood protection rainfall depth-area-duration relationship and isohyetal pattern of any storm that is considered reasonably characteristic of the region in which the watershed is located. If snow melt may be substan-tial, appropriate amounts shall be included with the flood-producing rainfall. When floods are predominantly caused by snowmelt, the Standard Project Flood shall be based on critical combinations of snow, temperature, and water losses.

(f) Structures, systems, and components which must with-stand the design basis earthquake to meet the requirements of paragraph (a) shall be designed using a suitable dynamic anal-ysis or a suitable qualification test to demonstrate that they can withstand the seismic and other concurrent loads, except where it can be demonstrated that the use of an equivalent static load method provides adequate censervatism.

(g) Conservative estimates of atmospheric dispersion of ha7ardous material based on local meteorological conditions shall be used to evaluate the impact of normal operations and of design basis accidents to demonstrate compliance with the requirements of paragraph (a).

Confinement barriers and systems.

Confinement systems shall consist of confinement barriers and equipment which control against the release of hazbrdous materials to the environment. The confinement systems which are significant to safety shall be designed to protect against the effects of accidents or external natural phenomena and snall be fabricated, erected, appropriately tested, and main-tained to ensure prevention of abnormal leakage, rapidly propagating failure, or gross rupture during the design life of the facility.

4 The techniques used in "U.S. Tornsdoes, Part 1, 70-Year Statistics, T. Theodore Fujita, the University of Chicago,"

"Historical Extreme Winds for the United States--Atlantic and Gulf of Mexico Coastlines, M.J. Changery, NOAA, May 1982 NUREG/CR-2639," and "Methodology for Estimating Extreme Winds i for Probabilistic Risk Assessments," J. V. Ramsdell, et al.,

l NUREG/CR-4492, PNL-5737, October 1986, to relate return period to design wind speed serve as examples of acceptable techniques.

Mean return periods of 10,000 years are likely to yield satis-factory design wind speeds.

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Compartmentalization of process inventory, when used as a method of reducing the amount of hazardous material capable of ,

being released by any single or local failure of primary con- J tainment, shall be considered in design as a means to effec-tively isolate and contain the process inventory in modular units or states for all reasonable normal or abnormal conditions.

l Ventilation systems.

Ventilation systems required for the confinement of hazardous materials shall be designed and appropriately tested to ensure their operability during normal or abnormal condi-ti or.s . To accomplish this objective, these systems shall be designed to meet the following requirements:

(a) The desired ventilating air flow direction shall be maintained under operating and accident conditions.

(b) The ventilation system shall accommodate changes in operating conditions, such as variations in temperature or pressure, and shall be capable of rafely controlling all off-gases that could be associated witt normal or accident conditions.

(c) The continuity of necessar/ ventilation shall be assured by means of alternate equipment, fail-safe systems, or other provisions.

(d) Provisions shall be made for testing, during normal operations, all component functions having safety significance to the extent necessary to provide reasonable assurance that they will perform their design safety functions.

(e) Ventilation systems shall be designed to permit the continued occupancy of any and all areas where such occupancy is required for normal plant operations, for safe shutdown, and for maintaining the facility in a safe shutdown condition.

Their design shall include protection against the intake and accumulation of hazardous materials. The design shall also permit the timely and safe evacuation of personnel from all l areas, i (f) Ventilation systems shall be designed to confine the hazardous materials during normal operation and to ensure that the release of hazardous materials in the effluent gases is as low as reasonably achievable. Such systems shall also be designed to retain their confinement and separation capability

+o minimize releases resulting from an accident condition.

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PROCESS SAFETY ,

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Protection systems.

1 (a) Protection systems shall be designed (1) to initiate j action that will assure that specified acceptable operating design limits are not exceeded as a result of operational occur-rences and (2) to sense potentially hazardous or accident condi- I tions, and to activate systems and components required to ensure i the safety of operating personnel and the public or to give audible and visual alarm so that action can be taken in a timely manner to ensure such safety. Systems and components shall be activated automatically where this mode is compatible with the safety requirements to be satisfied.

(b) Protection systems shall have reliability and in situ testability. The design of protection systems shall coniider alternate methods at least sufficient to ensure that (1) no single failure results in loss of the protection functions and (2) removal from service of any component does not result in loss of the protection system such that it will operate with acceptable reliability. The protection systems shall be designed to permit the periodic testing of their functions while the plant is in operation to determine competency to perform their intended safety functions.

(c) Protection system shall be designed to fail into a safe state or into a state demonstrated to be acceptable on some other defined basis if conditions such as disconnection of the system, loss of energy or motive power, or adverse environ-ments are experienced.

Instrumentation and control systems.

Instrumentation and control systems shall be provided to monitor variables and operating systems that are significant to safety over anticipated ranges for normal operation, for abnormal operation, for accident conditions, and for safe shut-down. These systems shall ensure adequate safety of process and utility service operations in connection with their safety function. The variables and systems that require constant surveillance and control include process systems having safety significance, the overall confinement system, confinement barriers and their associated systems, and other systems that affect the overall safety of the plant. Controls shall be provided to maintain these variables and systems within the prescribed operating ranges under all normal conditions.

Instrumentation and control systems shall be designed to fail into a safe state or to assume a state demonstrated to be acceptable on some other basis if conditions such as dis-connection, loss of energy or motive power, or adverse environments are experienced.

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Separation of protection systems and control systems.

Protection systems shall be separated from control systems to the extent that a change or failure in a control system leaves intact a protection system with acceptable reliability and independence requirements.

Control areas.

A control room or control areas shall be designed to permit occupancy and actions to be taken to operate the plant safely under normal conditions and under abnormal or accident conditions to either operate the plant safely or to shut down the plant and maintain the plant in a safe condition. There shall be an alternate system designed to allow the plant to be put into a safe condition if any one control room or control area is removed from service.

Process systems as primary confinement barriers.

Process components and systems are the primary confinement barrier. The design of each process system shall provide capa-bility for the system to maintain its integrity and operability as necessary to protect the public health and safety. Provi-sions shall be included for the safe handling of anticipated nonroutine process conditions.

Utility Services.

Onsite utility service systems shall be provided when such o'nsite service is necessary for emergency use to protect the health and safety of the public. Onsite utility services shall meet the following criteria:

(a) The design of each utility service system required for emergency conditions shall provide for the meeting of safety demands under normal and abnormal conditions. The design of utility services and distribution systems having safety significance shall include alternate systems to the extent necessary to maintain, with adequate capacity, the ability to perform safety functions assuming a single failure.

(b) Emergency utility services shall be designed to permit testing of their functional operability and capacity, including the full operational sequence of each system for transfer between normal and emergency supply sources, and the operation of associated safety systems.

(c) Provisions shall be made so that, in the event of a loss of the primary electric power source or circuit, reliable i and timely emergency power will be provided to instruments, l

confinement systems, utility service systems, and process I

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systems in amounts sufficient to allow operations to be shut down safely and to be maintained in a safe shutdown condition with all safety devices essential to safe shutdown functioning, NUCi. EAR CRITICALITY SAFETY Safety margins.

The design of process and storage systems shall include demonstrable margins of safety for the nuclear criticality parameters that are commensurate with the uncertainties in the process and storage conditions, in the data and methods used in calculations, and in the nature of the immediate environment under accident conditions. All process and storage systems shall be designed to be maintained subcritical and to ensure that no nuclear criticality accident can occur unless at least two unlikely, independent, and concurrent or sequential changes have occurred in the conditions essential to nuclear critical-ity safety.

Methods of control.

(a) Favorable geometry, in which equipment or systems are suberitical by virtue of neutron leakage under worst credible conditions, is the preferred method of nuclear criticality control.

(b) Where the favorable geometry method of nuclear criticality control is not practical, the use of permanently fixed neutron-absorbing materials (poisons) is the next pre-5 ferred method of control.

(c) Where both the favorable geometry and the permanently fixed neutron-absorbing materials (poisons) methods of nuclear criticality control are not practical, administrative controls of moderation, fissile material concentratione total fissile material, or the use of soluble neutron-absorbing materials (poisons) shall be employed when combined with margins of safety measurements or appropriate analysis and engineared safety features.

Neutron absorbers.

Where solid neutron-absorbing materials (poisons) are used for the prevention of nuclear criticality, the design shall provide for positive means to verify their continued efficacy.

Soluble neutron absorbing materials may be used as a primary nuclear criticality control provided (a) two independent methods are provided to ensure the presence of the required conuentration of neutron absorber and (b) the equipment con-

taining the fissile material is located behind sufficient barriers and shielding to reduce the probability and extent of accidental contamination of the environment and accidental radiation exposure to personnel in the event of a criticality accident.

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F Ancillary criteria for nuclear criticality safety.

(a) Process and storage systems shall be designed to ensure that no mechanisms that could cause segregation of fissile materials can be present in components whose nuclear criticality safety is dependent on the homogeneous distribu-tion of fissile material.

(b) Components whose nuclear criticality safety is dependent on a limiting concentration of fissile material shall be designed so that either (1) mechanisms that could cause critical concentrations of fissile materials are not present or (2) concentration is controlled by positive instrumental means.

(c) Process and storage systems shall be designed to ensure that the transfer of fissile material from safe systems to unsafe systems is not possible as a consequence of any single failure or operating error. ,

(d) Confinement system components shall be designed to ensure that leakage from equipment or from one confinement zone to another confinement Zone cannot result in a condition that wciuld result in nuclear criticality.

(s) The spacing between discrete accumulations of fissile materials shall be controlled so as to maintain a subcritical state.

4 (f) A criticality monitoring system shall be maintained '

in each area where special nuclear material is handled, used, or stored which will energize clearly audible alarm signals if accidental criticality occurs.

RADIOLOGICAL PROTECTION ,

Exposure control Radiation protection systems must be provided for all areas and operations where onsite personnel may be exposed to radiation or airborne radioactive materials. Structures, systems, and components for which operation, maintenance, and required inspections may involve occupational exposure must be designed, fabricated, located, shielded, controlled, and tested so as to control external and internal radiation exposures to personnel. The design must include means to:

(a) Prevent the accumulation of radioactive material in those systera requiring access; i (b) Decontaminate those systems to which access is -

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(c) Control access to areas of potential contamination or radiation; (d) Measure and control contamination of areas requiring access; (e) Minimize the time required to perform work in the vicinity of radioact es components; for example, by providing suffi:ient space for ease of operation and designing equipment for ease of repair and replacement; and (f) Shield personnel from radiation exposure.

Radiological alarm systems Radiological alarm systems must be provided in accessible work areas as appropriate to warn operating personnel of radiation and airborne radioactive material concentrations above a given setpoint and of concentrations of radioactive material in effluents above control limits. Radiation alarm systems must be designed with provisions for calibration and testing their operability.

Effluent and direct radiation monitorina (a) As appropriate affluent systas inust be provided.

Means for measuring the amount of radionuclides in effluents during normal operations and under accident conditions must be provided for these systems. A means of measuring the flow of the diluting medium, either air or water, must also be provided.

(b) Areas containing radioactive materials must be provided with systems for measuring the direct radiation levels in and around these areas.

l Effluent control Facilities must be designed to provide means to limit levels as low as is reasonably achievable the release of radioactive materials in effluents during normal operations; and control the release of radioactive materials under accident conditions.

Decommissioning The facility must be designed so as to facilitate decommissioning. Provisions must be made to facilitate i

decontamination of structures and equipment, and facilitate the l

removal of radioactive wastes and contaminated materials at the time the facility is permanently decommissioned.

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Review Plan Topics for NRC Staff The Commission has taken into account the information contained in the previous paragraphs in this notice, the information guidance set forth in Regulatory Guide 3.2.5, "Standard Format and Content of Safety Analysis Reports for Uranium Enrichment Facilities," and experience gained in previous evaluations of other types of fuel cycle facilities in order to determine the individual topics for its review and evaluation of the safety of a uranium enrichment facility. These topics are as follows: seismology, geology, hydrology, meteorology, site location factors, structural analysis, mechanical equipment analysis, criticality prevention, fire / explosion prevention and protection, ventilation system analysi % identificatinn ed shtring of structurc:, cycte::, and ccep -

nents important to safety, radioactive waste treatment, packaging, and disposal, radiation protection, chemical safety, accident analysis and emergency planning, decontamination and decommissioning, management organization and quality assurance, technical specifications, human factors, operator licensing, safeguarding special nuclear material, and the protection of classified information. It is expected that each of these topics will be addressed separately in any safety evaluation report prepared by the staff for a uranium enrichment facility.

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Questions Related to the Regulation of Uranium Enrichment Facilities In light of the previous discussion, the U.S. Nuclear Regulatory Commission is particularly interested in receiving comments concerning the following:

1. Are the siting criteria set forth in the General Design Criteria apprapriate and complete for uranium enrichment facilities?

2. Are there factors related to protection of the environment and the public other than the chemical toxicity of the reaction products of uranium hexafluoride, that are not taken into account in the. bounding conditions in the General Design Criteria?

3 Should the criteris cf ,^.ppandix 3 to 10 CFR P4rt 50, "Qualit,y Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants,"

be applied in its present form to uranium enrichment facilities?

4. What activities should be performed by a licensed operator and what requirements should apply?

5. Should the technical specification categories applicable to fuel reprocessing plants, as set forth in 10 CFR 50.36, be applied to uranium enrichment facilities?

6. Considering the discussion in this notict concerning the health effects to persons by the uptake of uranium, what value of uranium mass should be used for a basis of design calculation comparable to the twenty-five rem whole body value used for guidance in 10 CFR Part 100?

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List of Subjects for Proposed 10 CFR Part 76 Classified information, Hazardous substances, Penalty, Radiation protection, Reporting and recordkeeping requirements, Security measures, Source material, Special nuclear material, Uranium.

The authority citation for this document is: Sec. 161, 68 Stat. 948, as amended (42 U.S.C. 2201); see. 201, 88 Stat. 1242, as amended (42 U.S.C. 5841).

Dated at Rockville, MD this 18th day of April 1988.

For the Nuclear Regulatory Commission.

')

k-. T Eamuel J. Cr ,

3ecretary o the Commission.

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