9634 Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules

Paperwork Reduction Act

This proposed rule contains no

information collection or recordkeeping

requirements under the Paperwork

Reduction Act of 1980 (44 U.S.C. 3501

et seq.).

List of Subjects in 9 CFR Part 94

Animal diseases, Imports, Livestock,

Meat and meat products, Milk, Poultry

and poultry products, Reporting and

recordkeeping requirements.

Accordingly, 9 CFR part 94 would be

amended as follows:

PART 94—RINDERPEST, FOOT-ANDMOUTH DISEASE, FOWL PEST (FOWL

PLAGUE), VELOGENIC

VISCEROTROPIC NEWCASTLE

DISEASE, AFRICAN SWINE FEVER,

HOG CHOLERA, AND BOVINE

SPONGIFORM ENCEPHALOPATHY:

PROHIBITED AND RESTRICTED

IMPORTATIONS

1. The authority citation for part 94

would continue to read as follows:

Authority: 7 U.S.C. 147a, 150ee, 161, 162,

and 450; 19 U.S.C. 1306; 21 U.S.C. 111, 114a,

134a, 134b, 134c, 134f, 136, and 136a; 31

U.S.C. 9701; 42 U.S.C. 4331, and 4332; 7 CFR

2.17, 2.51, and 371.2(d).

§ 94.0 [Amended]

2. In § 94.0, the definition for Game

birds would be amended by adding ‘‘,

and wild turkeys’’ immediately

following the word ‘‘pheasants’’.

3. In § 94.0, the definition for Poultry

would be amended by removing

‘‘turkeys,’’ immediately following

‘‘Chickens,’’ and adding ‘‘turkeys,’’

immediately following ‘‘pen-raised’’.

Done in Washington, DC, this 13th day of

February 1995.

Lonnie J. King,

Acting Administrator, Animal and Plant

Health Inspection Service.

[FR Doc. 95–4178 Filed 2–17–95; 8:45 am]

BILLING CODE 3410–34–P

NUCLEAR REGULATORY

COMMISSION

10 CFR Chapter I

Issuance of Report on the NRC

Regulatory Agenda

AGENCY: Nuclear Regulatory

Commission.

ACTION: Issuance of NRC Regulatory

Agenda.

SUMMARY: The Nuclear Regulatory

Commission (NRC) has issued the NRC

Regulatory Agenda for the period

covering July through December, of

1994. This agenda provides the public

with information about NRC’s

rulemaking activities. The NRC

Regulatory Agenda is a compilation of

all rules on which the NRC has recently

completed action, or has proposed

action, or is considering action, and of

all petitions for rulemaking that the

NRC has received that are pending

disposition. Issuance of this publication

is consistent with Section 610 of the

Regulatory Flexibility Act.

ADDRESSES: A copy of this report,

designated NRC Regulatory Agenda

(NUREG–0936), Vol. 13, No. 3, is

available for inspection, and copying for

a fee, at the Nuclear Regulatory

Commission’s Public Document Room,

2120 L Street NW. (Lower Level),

Washington, DC.

In addition, the U.S. Government

Printing Office (GPO) sells the NRC

Regulatory Agenda. To purchase it, a

customer may call (202) 512–2249 or

write to the Superintendent of

Documents, U.S. Government Printing

Office, Post Office Box 37082,

Washington, DC 20013–7082.

FOR FURTHER INFORMATION CONTACT:

Michael T. Lesar, Chief, Rules Review

Section, Rules Review and Directives

Branch, Division of Freedom of

Information and Publications Services,

Office of Administration, U.S. Nuclear

Regulatory Commission, Washington,

DC 20555, Telephone: (301) 415–7163,

toll-free number (800) 368–5642.

Dated at Rockville, Maryland, this 1st day

of February 1995.

For the Nuclear Regulation Commission.

Michael T. Lesar,

Acting Chief, Rules Review and Directives

Branch, Division of Freedom of Information

and Publications Services, Office of

Administration.

[FR Doc. 95–4168 Filed 2–17–95; 8:45 am]

BILLING CODE 7590–01–M

10 CFR Part 50

RIN 3150–AF00

Primary Reactor Containment Leakage

Testing for Water-Cooled Power

Reactors

AGENCY: Nuclear Regulatory

Commission.

ACTION: Proposed rule.

SUMMARY: The Nuclear Regulatory

Commission is proposing to amend its

regulations to provide a performancebased option for leakage rate testing of

containments of light-water-cooled

nuclear power plants. This option will

be available for voluntary adoption by

licensees, in lieu of compliance with the

current prescriptive requirements

contained in the current regulation. This

action is aimed at improving the focus

of the regulations by eliminating

prescriptive requirements that are

marginal to safety. The proposed rule

would allow test intervals to be based

on system and component performance,

and provide licensees greater flexibility

for cost-effective implementation

methods of regulatory safety objectives.

DATES: Submit comments by May 8,

1995. Comments received after this date

will be considered if it is practical to do

so, but the Commission is able to assure

consideration only for comments

received on or before this date.

ADDRESSES: Send comments to:

Secretary, U.S. Nuclear Regulatory

Commission, Washington, DC 20555.

ATTN: Docketing and Service Branch.

Hand deliver comments to: 11555

Rockville Pike, Rockville, Maryland,

between 7:45 a.m. and 4:15 p.m. Federal

workdays.

Comments may be submitted

electronically, in either ASCII text or

Wordperfect format (version 5.1 or

later), by calling the NRC Electronic

Bulletin Board on FedWorld. The

bulletin board may be accessed using a

personal computer, a modem, and one

of the commonly available

communications software packages, or

directly via Internet. Background

documents on the rulemaking are also

available for downloading and viewing

on the bulletin board.

If using a personal computer and

modem, the NRC subsystem on

FedWorld can be accessed directly by

dialing the toll free number: 1–800–

303–9672. Communication software

parameters should be set as follows:

Parity to none, data bits to 8, and stop

bits to 1 (N,8,1). Using ANSI or VT–100

terminal emulation, the NRC

rulemaking subsystems can then be

accessed by selecting the ‘‘Rules Menu’’

option from the ‘‘NRC Main Menu.’’ For

further information about options

available for NRC at FedWorld consult

the ‘‘Help/Information Center’’ from the

‘‘NRC Main Menu.’’ Users will find the

‘‘FedWorld Online User’s Guides’’

particularly helpful. Many NRC

subsystems and databases also have a

‘‘Help/Information Center’’ option that

is tailored to the particular subsystem.

The NRC subsystem on FedWorld can

also be accessed by a direct dial phone

number for the main FedWorld BBS:

703–321–8020; Telnet via Internet:

fedworld.gov (192.239.93.3); File

Transfer Protocol (FTP) via Internet:

ftp.fedworld.gov (192.239.92.205); and

World Wide Web using: http://
Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules 9635

1Copies of NUREGs 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

available for inspection and/or copying in the NRC

Public Document Room, 2120 L Street, NW. (Lower

Level), Washington, DC.

www.fedworld.gov (this is the Uniform

Resource Locator (URL)).

If using a method other than the toll

free number to contact FedWorld, then

the NRC subsystem will be accessed

from the main FedWorld menu by

selecting the ‘‘F—Regulatory,

Government Administration and State

Systems,’’ then selecting ‘‘A—

Regulatory Information Mall’’. At that

point, a menu will be displayed that has

an option ‘‘A—U.S. Nuclear Regulatory

Commission’’ that will take you to the

NRC Online main menu. You can also

go directly to the NRC Online area by

typing ‘‘/go nrc’’ at a FedWorld

command line. If you access NRC from

FedWorld’s main menu, then you may

return to FedWorld by selecting the

‘‘Return to FedWorld’’ option from the

NRC Online Main Menu. However, if

you access NRC at FedWorld by using

NRC’s toll-free number, then you will

have full access to all NRC systems, but

you will not have access to the main

FedWorld system. For more information

on NRC bulletin boards call Mr. Arthur

Davis, Systems Integration and

Development Branch, U.S. Nuclear

Regulatory Commission, Washington,

DC 20555, telephone (301) 415–5780; email AXD3@nrc.gov.

Examine comments received, the draft

environmental assessment and findings

of no significant impact, and the draft

regulatory analysis at: The NRC Public

Document Room, 2120 L Street NW.

(Lower Level), Washington, DC; the

PDR’s mailing address is Mail Stop LL–

6, Washington, DC 20555; phone (202)

634–3273; fax (202) 634–3343. Copies of

the documents may be obtained from

the PDR for a fee. These documents may

also be viewed and downloaded

electronically via the Electronic Bulletin

Board established by NRC for this

rulemaking.

The NRC also requests public

comment on Draft NUREG–1493,

‘‘Performance-Based Containment Leak

Test Program.’’ A free single copy of

draft NUREG–1493 may be requested by

written request to the U.S. Nuclear

Regulatory Commission, ATTN:

Distribution Section, Room P1–37,

Washington, DC 20555; fax (301) 504–

2260. Comments on draft NUREG–1493

may be submitted to: Chief, Rules

Review and Directives Branch, Division

of Freedom of Information and

Publication Services, Mail Stop T–6D59,

U.S. Nuclear Regulatory Commission,

Washington, DC 20555. Hand deliver

comments on draft NUREG–1493 to

11545 Rockville Pike, Maryland

between 7:45 a.m. and 4:15 p.m. on

Federal workdays. Comments on draft

NUREG–1493 may be submitted

electronically as indicated above under

the ADDRESSES heading.

FOR FURTHER INFORMATION CONTACT: Dr.

Moni Dey, Office of Nuclear Regulatory

Research, U.S. Nuclear Regulatory

Commission, Washington, DC 20555,

telephone (301) 415–6443, e-mail

mkd@nrc.gov

SUPPLEMENTARY INFORMATION:

Background

The NRC is proposing to amend 10

CFR part 50, appendix J in an effort to

relax and allow alternatives to those

requirements that are prescriptive and

marginal to safety and yet impose a

significant regulatory burden on

licensees. NRC reactor licensees are

required currently to conduct periodic

primary reactor containment leakage

testing in accordance with 10 CFR part

50, appendix J, ‘‘Primary Reactor

Containment Leakage Testing for WaterCooled Power Reactors.’’ Appendix J is

currently prescriptive in that it specifies

leak test frequencies, pretest

requirements, test methods, and

reporting requirements.

NRC’s Marginal to Safety/Regulatory

Improvement Program

In 1984, the NRC staff initiated a

program to make regulatory

requirements more efficient by

eliminating those with marginal impact

on safety. The NRC’s initiative to

eliminate requirements marginal to

safety recognizes both the dynamic

nature of the regulatory process and that

the importance and safety contribution

of some existing regulatory

requirements may not have been

accurately predicted when adopted or

may have diminished with time. The

availability of new technical

information and methods justify a

review and modification of existing

requirements.

The NRC solicited comments from

industry on specific regulatory

requirements and associated regulatory

positions that needed reevaluation. The

Atomic Industrial Forum conducted a

survey providing most of industry’s

input, published for the NRC as

NUREG/CR–4330 1, ‘‘Review of Light

Water Reactor Regulatory

Requirements,’’ Vol. 1, April 1986. A

list of 45 candidates for potential

regulatory modification were identified.

The NRC’s review of the list selected

Appendix J as one of seven areas

requiring further analysis (NUREG/CR–

4330, Vols. 2 and 3, dated June 1986

and May 1987). The NRC also

conducted a survey of its staff

concerning their expertise in a

particular area, experience in regulation,

and knowledge of regulatory

requirements. The NRC staff survey

identified 54 candidates, a number of

which were previously identified in the

earlier survey. The NRC’s assessment of

this list also selected appendix J as a

potential candidate for modification.

The NRC published in the Federal

Register, for comment, a proposed

revision to appendix J on October 29,

1986 (51 FR 39538) to update

acceptance criteria and test methods

based on experience in applying the

existing requirements and advances in

containment leak testing methods,

resolve interpretive questions, and

reduce the number of exemption

requests. The October 29, 1986,

proposed rule is being withdrawn from

further consideration and a more

comprehensive proposed rule that

accounts for the latest technical

information and regulatory framework is

being proposed.

The NRC’s Marginal-to-Safety

initiative is part of a broader NRC

initiative for regulatory improvement.

Through its Program for Regulatory

Improvement, the NRC has

institutionalized an ongoing effort to

eliminate requirements marginal to

safety and to reduce regulatory burden.

The NRC staff’s plan in SECY–94–090,

dated March 31, 1994, which satisfies

the recent requirement for a periodic

review of existing regulations in

Executive Order 12866 of September 30,

1993, was approved by the Commission

on May 18, 1994. The Regulatory

Improvement Program is aimed at the

fundamental principle adopted by the

Commission that all regulatory burdens

must be justified and that its regulatory

process must be efficient. In practice,

this means the elimination or

modification of requirements where

burdens are not commensurate with

their safety significance. The activities

of the Regulatory Improvement Program

should result in enhanced regulatory

focus in areas that are more safety

significant. As a result, an overall net

increase in safety is expected from the

program.

The Regulatory Improvement Program

will include, whenever feasible and

appropriate, the consideration of

performance-oriented and risk-based

approaches. The program will review

requirements or license conditions that

are identified as a significant burden on
9636 Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules

licensees. If review and analysis find

that the requirements are marginal to

safety, they would be eliminated or

relaxed. By performance-oriented, the

NRC means establishing regulatory

objectives without prescribing the

methods or hardware necessary to

accomplish the objective, and allowing

licensees the flexibility to propose costeffective methods for implementation.

By risk-based, the NRC means

regulatory approaches that use

probability risk analysis (PRA) as the

systematic framework for developing or

modifying requirements.

The present rulemaking is part of this

overall effort and initiative for

eliminating requirements that are

marginal to safety and is guided by the

policies, framework and criteria for the

program.

The NRC published a notice in the

Federal Register on February 4, 1992

(57 FR 4166), presenting its conclusion

that appendix J was a candidate whose

requirements may be relaxed or

eliminated based on cost-benefit

considerations. On the basis of NRC

staff analyses of public comments on the

proposal, the Commission approved and

announced on November 24, 1992 (57

FR 55156) its plans to initiate

rulemaking for developing a

performance-oriented and risk-based

regulation for containment testing

requirements. On January 27, 1993, (58

FR 6196) the NRC staff published a

general framework for developing

performance-oriented and risk-based

regulations and, at a public workshop

on April 27 and 28, 1993, invited

discussions of specific proposals for

modifying containment testing

requirements. Industry and public

comments on the proposals, and other

recommendations and innovative ideas

raised at the public workshop, were

documented in the proceedings of the

workshop (NUREG/CP–0129, September

1993). Specifically, the NRC concluded

that the allowable containment leakage

rate utilized in containment testing may

be increased and other Appendix J

requirements need not be as prescriptive

as the current requirements. To increase

flexibility, the detailed and prescriptive

technical requirements contained in

appendix J regulations could be

improved and replaced with

performance-based requirements and

supporting regulatory guides. The

regulatory guides would allow

alternative approaches, although

compliance with current existing

regulatory requirements would continue

to be acceptable. The performance-based

requirements would reward superior

operating practices.

Performance-Based Regulatory

Approach

In institutionalizing the Regulatory

Improvement program and adopting a

performance-based regulatory approach,

the NRC has formulated the following

framework for revisions to its

regulations:

(1) The new performance-based

regulation will be less prescriptive and

allow licensees flexibility to adopt costeffective methods for implementing the

safety objectives of the original rule.

(2) The regulatory safety objectives

will be derived, to the extent feasible

and practical, from risk considerations

with appropriate consideration of

uncertainties, and will be consistent

with the NRC’s Safety Goals.

(3) Detailed technical methods for

measuring or judging the acceptability

of a licensee’s performance relative to

the regulatory safety objectives will be,

to the extent practical, provided in

industry standards and guidance

documents which are endorsed in NRC

regulatory guides.

(4) The new regulation will be

optional for current licensees so that

licensees can decide to remain in

compliance with current regulations.

(5) The regulation will be supported

by necessary modifications to, or

development of, the full body of

regulatory practice including, for

example, standard review plans,

inspection procedures, guides, and

other regulatory documents.

(6) The new regulation will be

formulated to provide incentives for

innovations leading to improvements in

safety through better design,

construction, operating, or maintenance

practices.

Current Appendix J Requirements

Appendix J to 10 CFR part 50,

‘‘Primary Reactor Containment Leakage

Testing for Water-Cooled Power

Reactors,’’ became effective on March

16, 1973. The regulatory safety objective

of reactor containment design is stated

in 10 CFR part 50, appendix A, ‘‘General

Design Criteria for Nuclear Power

Plants,’’ Criterion No. 16, ‘‘Containment

Design.’’ GDC Criterion 16 mandates

‘‘an essentially leak-tight barrier against

the uncontrolled release of radioactivity

to the environment * * *’’ for

postulated accidents. Appendix J to 10

CFR part 50 implements, in part,

General Design Criterion No. 16 and

specifies containment leakage testing

requirements, including the types of

tests required. For each type of test

required, Appendix J specifies how the

tests should be conducted, the

frequency of testing, and reporting

requirements. Appendix J requires the

following types of containment leak

tests:

(1) Measurement of the containment

integrated leak-rate (Type A tests, often

referred to as ILRTs).

(2) Measurement of the leak-rate

across each pressure-containing or

leakage-limiting boundary for various

primary reactor containment

penetrations (Type B tests).

(3) Measurement of the containment

isolation valves leak-rates (Type C tests).

Type B and C tests are referred to as

local leak-rate tests (LLRTs).

Leak-Tightness Requirements

Compliance with 10 CFR part 50,

appendix J, requirements is determined

by comparing the measured

containment leak-rate with the

maximum allowable leak rate.

Maximum allowable leak-rates are

calculated in accordance with 10 CFR

Part 100, ‘‘Reactor Site Criteria,’’ and are

incorporated into the technical

specifications. Typical allowable leakrates are 0.1 percent of containment

volume per day for pressurized water

reactors (PWRs) and one volume percent

per day for boiling water reactors

(BWRs).

Test Frequency Requirements

Schedules for conducting

containment leak-rate tests are specified

in appendix J for both preoperational

and periodic tests. Periodic leak-rate

tests schedules are as follows:

Type A Tests. (1) After the

preoperational leak-rate test, a set of

three Type A tests must be performed at

approximately equal intervals during

each 10-year service period. The third

test of each set must be conducted when

the plant is shutdown for the 10-year

plant in-service inspection.

(2) The performance of Type A tests

must be limited to periods when the

plant facility is nonoperational and

secured in the shutdown condition

under the administrative control and in

accordance with the safety procedures

defined in the license.

(3) If any periodic Type A test fails to

meet the applicable acceptance criteria,

the test schedule applicable to

subsequent Type A tests will be

reviewed and approved by the

Commission. If two consecutive

periodic Type A tests fail to meet the

applicable acceptance criteria, a Type A

test must be performed at each plant

shutdown for refueling or

approximately every 18 months,

whichever occurs first, until two

consecutive Type A tests meet the

acceptance criteria, after which time the

regular retest schedule may be resumed.
Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules 9637

2Severe Accident Risks: An assessment for five

U.S. Nuclear Power Plants, Final Summary Report.’’

NUREG–1150, December 1990. Copies of NUREGs

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 available for

inspection and/or copying in the NRC Public

Document Room, 2120 L Street, NW. (Lower Level),

Washington, DC.

3Performance-Based Containment Leak Test

Program,’’ Draft NUREG–1493, January 1995. A free

single copy of draft-1493 may be requested by those

considering public comment by writing to the U. S.

Nuclear Regulatory Commission, ATTN:

Distribution Section, Room P1–37, Washington, DC

20555. A copy is also available for inspection and/

or copying in the NRC Public Document Room,

2120 L Street, NW. (Lower Level), Washington, DC

20555.

Type B Tests. (1) Except for airlocks,

Type B tests must be performed during

reactor shutdown for refueling, or other

convenient intervals, but in no case at

intervals greater than 2 years. If opened

following a Type A or B test,

containment penetrations subject to

Type B testing must be tested prior to

returning the reactor to an operating

mode requiring containment integrity.

For primary reactor containment

penetrations employing a continuous

leakage monitoring system, Type B tests,

except for tests of airlocks, may be

performed every other reactor shutdown

for refueling but in no case at intervals

greater than 3 years.

(2) Airlocks must be tested prior to

initial fuel loading and at 6-month

intervals thereafter. Airlocks opened

during periods when containment

integrity is not required by the plant’s

technical specifications must be tested

at the end of such periods. Airlocks

opened during periods when

containment integrity is required by the

plant’s technical specifications must be

tested within 3 days after being opened.

For airlock doors opened more

frequently than once every 3 days, the

airlock must be tested at least once

every 3 days during the period of

frequent openings. For airlock doors

having testable seals, testing the seals

fulfills the 3-day test requirement.

Airlock door seal testing must not be

substituted for the 6-month test of the

entire airlock at not less than Pa, the

calculated peak containment pressure

related to the design basis accident.

Type C Tests. Type C tests must be

performed during each reactor

shutdown for refueling but in no case at

intervals greater than 2 years.

There have been two amendments to

this appendix since 1973. The first

amendment published September 22,

1980 (45 FR 62789), modified the Type

B penetration test requirements to

conform to what had become accepted

practice through the granting of

exemptions. The second amendment

published November 15, 1988 (53 FR

45890) incorporated the Mass Point

statistical analysis technique as a

permissible alternative to the Total

Time and Point-to-Point techniques

specified in appendix J.

European Experience

A combination of Type A tests and an

on-line monitoring (OLM) capability is

being actively pursued in Europe,

notably in France and Belgium, and is

currently being considered in Sweden.

OLM is used to identify a ‘‘normal’’

containment pressurization pattern and

to detect deviations from that pattern.

The Belgians conduct a leak test using

OLM during reactor operation after each

cold shutdown longer than 15 days with

the objective of detecting gross leaks.

The objective of the Belgian approach to

Type A testing is to reduce the

frequency and duration of the tests. The

Type A test is conducted at a

containment pressure (Pt) not less than

half of the peak pressure (0.5 Pa). It is

performed once every 10 years.

In France, containment leaktightness

is being continuously monitored during

reactor operation in all of the French

PWR plants using the SEXTEN system.

It is also being evaluated by the Swedes

for their PWR units. Leaks may be

detected during the positive or negative

pressure periods in the containment by

evaluating the air mass balance in the

containment. Type A tests are

conducted at containment peak pressure

(loss-of-coolant accident pressure)

before initial plant startup, during the

first refueling, and thereafter every 10

years unless a degradation in

containment leak-tightness is detected.

In that case, tests are conducted more

frequently.

Further details of European

approaches to containment testing is

provided in Draft NUREG–1493.

Advance Notices for Rulemaking and

Public Comments

Over time, it has become apparent

that variations in plant design and

operation frequently make it difficult to

meet some of the requirements

contained in appendix J because of its

prescriptive nature. Economic and

occupational exposure costs are directly

related to the frequency of containment

testing. Containment integrated leak rate

tests (Type A) preclude any other

reactor maintenance activities and thus

are on the critical path for return to

service from reactor outages. In addition

to the costs of the tests, integrated leak

tests impose the added burden of the

cost of replacement power. Containment

penetration leak tests (Type B and C)

can be conducted during reactor

shutdowns in parallel with other

activities and thus tend to be less costly;

however, the large number of

penetrations impose a significant

burden on the utilities. Additionally,

risk assessments performed to date

indicate that the allowable leak rate

from containments can be increased,

and that control of containment leakage

at the current low rates is not as risk

significant as previously assumed.2 3

Initial NRC Proposal

In August of 1992, the Commission

initiated a rulemaking to modify

appendix J to make it less prescriptive

and more performance-oriented. The

Commission also initiated a plan to

relax the allowable containment leakrate utilized to define performance

standards for containment tests. In the

Federal Register published on January

27, 1993 (58 FR 6196), the NRC

indicated the following potential

modifications to appendix J of 10 CFR

part 50 would be considered:

(1) Increase allowable containment

leak-rates based on Safety Goals and

PRA technology (i.e., define a new

performance standard).

(2) Modify appendix J to be a

performance-based regulation:

A Limit the revised rule to a new

regulatory objective: In order to ensure

the availability of the containment

during postulated accidents, licensees

should either:

(i) Test overall containment leakage at

intervals not longer than every 10 years,

and test pressure-containing or leakagelimiting boundaries and containment

isolation valves on an interval based on

the performance history of the

equipment; or

(ii) Provide on-line (i.e., continuous)

monitoring of containment isolation

status.

B Remove prescriptive requirements

from appendix J and preserve useful

portions as guidance in a NRC

regulatory guide.

C Endorse industry standards on:

(i) Guidance for calculating plantspecific allowable leak-rates based on

new NRC performance standard;

(ii) Guidance on the conduct of

containment tests; and

(iii) Guidance for on-line monitoring

of containment isolation status.
9638 Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules

4 ‘‘Workshop on Program for Elimination of

Requirements Marginal to Safety.’’ NUREG/CP–

0129, September 1994.

D Continue to accept compliance

with the current detailed requirements

in appendix J (i.e., licensees presently in

compliance with Appendix J will not

need to do anything if they do not wish

to change their practice).

A public workshop on the subject was

held by the NRC on April 27 and 28,

1993.4

Public Comments and Issues

Listed below are the categories of

relevant issues identified by the public,

the nuclear industry, and the NRC at the

public workshop and in response to

earlier solicitations for comments on

this rulemaking, and a summary of

interests expressed. Summaries of

individual comments earlier

solicitations were published on

November 1992 (57 FR 55156). The

comments at the public workshop are

documented in NUREG/CP–0129,

September 1993. The comments are

available for inspection in the NRC

Public Document Room.

1. Is there a continuing need for this

regulation?

Most commenters agree that there is a

continuing need for a regulation on

containment leak testing. While some

commenters believe the regulation

should be tightened, most commenters

believe appendix J requirements should

be relaxed. Industry representatives

presented a wealth of data on the cost

and benefits of containment leak testing.

2. Should the NRC replace appendix

J to 10 CFR part 50, ‘‘Primary Reactor

Containment Leak Testing for WaterCooled Power Reactors,’’ with a nonprescriptive, performance-based rule?

One commenter believed that using

conservatism that may far exceed

performance-based regulations is in the

public’s interest. Some misallocation of

resources does exist that could be

corrected, although there may be

varying opinions concerning where they

are. One commenter believed that, from

a public perception viewpoint, there

would be dissatisfaction with changing

to performance-based regulation. It

appears to represent a streamlining or

deregulation of standards. Another view

held that because there is no consistent

regulatory basis, there are

inconsistencies in regulation.

Performance-based regulations would

get rid of these inconsistencies. A move

to performance-based regulations would

uncover marginal requirements.

Performance-based requirements would

depend on the functional importance of

a component and might include

deterministic performance standards for

components. A component that did not

meet the performance standard would

be rejected. Another view was that the

industry can use increased knowledge

about reactors and regulations within

the existing technology to improve the

regulations and reduce risk, without

relying on risk assessments. This

approach might result in earlier

benefits. Industry generally encouraged

the NRC to proceed with its initiative to

decrease the prescriptiveness of its

regulations and adopt more

performance-based approaches.

3. Should the NRC increase allowable

containment leakage rates?

Some commenters believe that the

existing appendix J requirements for

allowable leakage should not be relaxed

and, based on their interpretation of

NUREG/CR–5747, ‘‘Estimate of

Radionuclide Releases Characteristics

into Containment Under Severe

Accident Conditions,’’ suggests that

more stringent leakage limits, not

relaxation of these requirements, is

appropriate. Because the current leakage

rates specified in plant technical

specifications are based on relatively

conservative assumptions, the majority

of commenters believe that a more

realistic representation of loss-ofcoolant accidents should be used to

calculate dose to the public. These

commenters believe that more realistic

accident scenarios would support a

relaxation in the containment leak-rate.

4. Should the NRC decrease Type A,

B, and C test frequencies?

While some commenters had opinions

on proper test frequencies, and most

believed that test frequencies could be

relaxed, overall, the technical

community believed that examination of

the technical data and the objectives of

the test should be used to determine the

appropriate test frequency. One

commenter believed that both increased

and decreased frequencies might be

appropriate. For example, tests might be

increased in frequency for valves that

play a risk-significant role, and test

interval or allowable leak-rate could be

increased for less important

components.

5. Can the new rule and its

implementation yield an equivalent

level of, or only have a marginal impact

on, safety?

Most commenters believe that a move

to performance-based regulations would

uncover marginal requirements. Some

believe that by conserving resources in

areas where safety is not a significant

issue, more resources can be devoted to

more risk-significant areas with a net

increase in the overall safety margin.

6. Can the regulatory/safety objective

(qualitative or quantitative) be

established in an objective manner to

allow a common understanding between

licensees and the NRC on how the

performance or results will be measured

or judged?

Several commenters believe that the

regulatory process should integrate

deterministic, risk-based, and

performance-based regulation and allow

for case-specific evaluation, with a goal

of protecting the health and safety of the

public and at the same time minimizing

the cost to the licensee. Others believe

that the opinions of public interest

groups should also be sought in deriving

safety goals/objectives. Overall, no

comments were presented that would

suggest that a common understanding

could not be achieved on goals and

performance measurements.

7. Can the regulation and

implementation documents be

developed in such a manner that they

can be objectively and consistently

inspected and enforced against?

Several commenters believe that the

regulations should be performancebased and the associated guidance

documents should be prescriptive so

that only the guidance documents not

the regulations will need to be changed

as more information is gained on

compliance issues. Many commenters

believe that PRAs should not be the sole

basis for regulatory decisions due to the

uncertainty in their results; however, if

the results indicate that a particular

requirement has a contribution to risk

significantly below the Safety Goal

thresholds, the PRA information should

be considered sufficient to justify

elimination of the requirement as

marginal to safety.

Proposed Revision

Based on several advance notices for

rulemaking and significant public

comment and discussion, risks and

costs evaluated, and consideration of

which modifications are feasible and

practical at this time, the NRC proposes

two phases for modifications of

requirements to containment leakage

testing. The first phase, for which

modifications are proposed in this

notice, will allow leak-rate testing

intervals to be based on the performance

of the containment system structures

and components. The second phase will

further examine the needed

requirements of the containment

function (i.e. structural and leak-tight

integrity of containment system

structures and components, and

prevention of inadvertent bypass), and

include consideration of the potential of

on-line monitoring of containment
Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules 9639

integrity to verify certain functions.

Solicitation of public comments to

guide this future work is included later

in this notice.

The rule proposed in this notice

would apply to all NRC licensees who

operate light water power reactors. The

proposed rule would allow licensees the

option of continuing to comply with the

current appendix J or to adopt the new

performance-based standards.

The NRC’s analyses are based upon

the insight gained through the use of

probability risk assessment techniques

and the significant data base of

practical, hands-on operating

experience gained since appendix J was

promulgated in 1973. This operating

experience provides hard evidence of

the activities necessary to conduct

appendix J testing, and the costs of

those activities both in monetary terms

and occupational radiation exposure.

The results of the present effort

documented in draft NUREG–1493,

which are based on NUREG–1150,

confirm previous observations of

insensitivity of population risks from

severe reactor accidents to containment

leak-rates.

The current appendix J requirements

have achieved the regulatory criteria of

assuring an essentially leak-tight

boundary between the power reactor

system and the external environment

(GDC Criterion 16). Costs associated

with complying with current appendix

J requirements are estimated to be

$165,000 for a complete battery of Type

B/C tests and $1,890,000 for Type A

tests. Over the average reactor’s

remaining lifetime of 20 years, the

present value of all remaining leak

testing at a five percent discount rate is

about $7 million per reactor. Estimates

of the remaining industry-wide costs of

implementing current appendix J

requirements range from $720 to $1,080

million, approximately 75 percent of

which could be averted with a

performance-based rule.

The present study found that by

allowing requirements with marginal

effect on safety, but which impose a

significant cost on licensees, to remain

in effect is to essentially misallocate a

portion of the NRC’s and the industry’s

resources on activities for which there is

no commensurate return in safety. The

real cost then may be in a missed

opportunity to focus NRC and licensee

efforts to areas where the return in terms

of added public safety is higher.

Specific alternatives for modifying the

current appendix J were identified by

the public in response to the NRC’s

Federal Register notice published on

January 27, 1993 (58 FR 6196). Those

whose characteristics matched the

NRC’s established criteria for the

marginal to safety program were

selected for further review.

Modifications of Initial Proposals

Allowable Leakage Rate

The NRC had initially planned to

establish, by rulemaking, a risk-based

allowable leak-rate commensurate with

its significance to total public risk.

Specific findings from draft NUREG–

1493 on the allowable leakage rate

include:

1. Allowable leakage can be increased

approximately two orders of magnitude

(100–200 fold) with marginal impact on

population dose estimates from reactor

accidents.

2. Calculated mean population risks

are several orders of magnitude below

the NRC’s Safety Goals for all reactors

considered, but the tail of the

distribution can approach Safety Goals.

3. Increases in the allowable leak-rate

is estimated to have a negligible impact

on occupational exposure.

Relaxing the allowable leak-rate is

estimated to reduce future industry

testing costs by $50 to $110 million, a

ten percent decrease in overall leak-rate

testing costs.

A risk-based allowable leakage rate

would be based on an evaluation, using

PRA, of the sensitivity and significance

of containment leakage to risk, and

determining an appropriate containment

leakage limit commensurate with its

significance to the risk to the public and

plant control room operators. However,

this would entail a major change in

policy and restructuring of the current

licensing basis and a more complete

understanding of the uncertainties

associated with the threat of severe

accidents to the containment, and

therefore, the NRC plans to consider a

modification of the performance

standard (allowable leakage level) in the

second phase separate from

modifications of testing requirements.

This modification will be part of a

broader effort to further examine the

risk significance of various attributes of

containment performance, i.e. structural

and leak-tight integrity of containment

system structures and components, and

inadvertent bypass.

On-Line Monitoring (OLM) Systems

Currently, there is no requirement for

OLM systems which monitor the

containment to detect unintentional

breaches of containment integrity.

Studies discussed in draft NUREG–

1493, ‘‘Performance-Based Containment

Leak Test Program,’’ find that, based on

operating experience, OLM would not

significantly reduce the risk to the

public from nuclear plant operation

and, thus, cannot be justified solely on

risk-based considerations. Specific

findings include:

1. Continuous monitoring methods

that exist appear technically capable of

detecting leaks in reactor containments

within 1 day to several weeks. OLM

systems are in use or planned in several

European countries.

2. OLM systems are only capable of

detecting leaks in systems that are open

to the containment atmosphere during

normal operation (approximately ten

percent of the mechanical penetrations).

3. The technical and administrative

objectives of OLM systems and Type A

tests are different.

4. OLM cannot be considered as a

complete replacement for Type A tests

because it cannot challenge the

structural and leak-tight integrity of the

containment system at elevated

pressures.

5. Analysis of the history of operating

experience indicates limited need for,

and benefit of, OLM in the U.S.

Although OLM cannot be justified

solely based on risk considerations, a

plant already possessing such a system

has greater assurance of achieving

certain attributes of containment

integrity. Therefore, OLM systems could

contribute towards an overall leakage

monitoring scheme. Some capability for

on-line monitoring already exists as a

byproduct of specific containment

designs. For example, licensees with

inerted BWR containments, or

subatmospheric PWR containments,

would readily detect gross leakages that

develop during normal operation.

Given that the application of on-line

monitoring is specific to containment

design, and generic application cannot

be justified solely on risk

considerations, the NRC does not

propose a requirement for OLMs.

However, licensees which already have

such a capability (e.g. inerted BWR

containments, and subatmospheric PWR

containments) are encouraged to

propose plant-specific application of

such a capability, including credit for

any added assurance for certain

attributes of containment integrity

provided by such a system compared to

other testing methods. The NRC will

reconsider the role of OLM in the

second phase of modifications in this

area along with the allowable leakage

rate.

Proposed Modification of Type A, B, C

Test Intervals

The NRC proposes at this time, for the

first phase of modifications, to define a

new risk-based regulation by utilizing

the performance history of components
9640 Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules

(containment, penetrations, valves) as

the means to justify an increase in the

testing interval for Type A, B, and C

tests. The revised regulation would

require tests to be conducted on an

interval based on the performance of the

containment structure, penetration or

valves without specifying the interval in

the regulation. Currently, three Type A

tests are conducted in every 10 year

period. Type B (except airlocks, which

are tested more frequently) and C tests

are conducted on a frequency not to

exceed 2 years.

The NRC proposes to base the

frequency of Type A tests (ILRTs) on the

historical performance of the overall

containment system. Specific findings

documented in draft NUREG–1493 that

justify the proposal include:

1. The fraction of leakages detected

only by ILRTs is small, on the order of

a few percent.

2. Reducing the frequency of ILRT

testing from three per 10 years to one

per 10 years leads to a marginal increase

in risk.

3. ILRTs also test the strength of the

containment structure. No alternative to

ILRTs have been identified to provide

assurance that the containment

structure will meet allowable leakage

rates during design-basis accidents.

4. At a frequency of one test per 10

years, industry-wide occupational

exposure would be reduced by 0.087

person-sievert (8.7 person-rem) per year.

Based on specific, detailed analyses of

data from the North Anna and Grand

Gulf plants and data from twenty-two

nuclear plants (see draft NUREG–1493),

performance-based alternatives to

current LLRT methods are feasible with

marginal impact on risk. Specific

findings that justify the proposal

include:

1. Type B and C tests detect a very

large fraction, over 97 percent of

containment leakages.

2. Of the 97%, virtually all leakages

are identified by LLRTs of containment

isolation valves (Type C tests).

3. Based on the detailed evaluation of

the experience of a single 2-unit station,

no correlation of failures with type of

valve or plant service could be found.

4. For the 20 years of remaining

operations, changing the Type B/C test

frequency alone is estimated to reduce

industry-wide occupational exposure by

0.72 person-sievert (72 person-rem) per

year. If 20-year license extension is

assumed, the estimate is 0.75 personsievert (75 person-rem) per year.

Reducing the frequency of ILRTs will

reduce future industry testing costs by

approximately $330 to $660 million if

tests are conducted once per 10 years

versus the current three per ten years.

These savings represent about 65

percent of the remaining costs of current

appendix J requirements. Performancebased LLRT alternatives are estimated to

reduce future industry testing costs by

$40 million to $55 million. These

savings represent about five percent of

the total remaining costs of appendix J

testing.

Therefore, based on the risks and

costs evaluated, and other

considerations discussed above, a

performance-based appendix J which

encompasses the following principles

which differ moderately from those first

described in the Federal Register

(January 27, 1993 58 FR 6197) is

proposed:

General. (1) Make appendix J less

prescriptive and more performanceoriented; (2) Move details of appendix J

tests to a regulatory guide as guidance;

(3) Endorse approved industry guideline

(NEI 94–01) on guidance on the conduct

of containment tests in a regulatory

guide. The methods for testing are

contained in an industry standard

(ANSI/ANS 56.8–1994) which is

referenced in the NEI guideline; (4)

Allow voluntary adoption of the new

regulation, i.e., current detailed

requirements in appendix J will

continue to be acceptable for

compliance with the modified rule.

Leakage Limits. Acknowledge the less

risk-significant nature of allowable

containment leakage (La) but pursue its

modification as a separate action.

Type A Test Interval. (1) Based on the

limited value of integrated leak-rate

tests (ILRTs) in detecting significant

leakages from penetrations and isolation

valves, establish the test interval based

on the performance of the containment

system structure; (2) The performance

criterion of the test will continue to be

the allowable leakage rate (La); (3) The

industry guideline allows extension of

the Type A test interval to once every

10 years based on satisfactory

performance of two previous tests; (4) In

the regulatory guide, the NRC has

included an exception for the extension

of the interval of the general visual

inspection of the containment system,

and limited the interval to three times

every 10 years as is current practice.

Type B & C Test Interval. (1) Allow

local leak-rate test (LLRTs) intervals to

be established based on the experience

history of each component; (2) The

performance criterion for the tests will

continue to be the allowable leakage rate

(La); (3) Specific performance criteria

and factors for establishing extended

test intervals (up to 10 years for Type B

components, and 5 years for Type C

components) are contained in the

regulatory guide and industry guideline.

In the regulatory guide, the NRC has

included an exception to the extension

of Type C test intervals up to 10 years

that is proposed in the NEI industry

guideline, and limited such extensions

to 5-years.

Specific Areas for Public Comment

In its preliminary criteria for

developing performance-based

regulations, the NRC identified three

issues to be addressed by the

rulemaking process as a measure of the

viability of the revised rule. These

issues have been addressed in the

rulemaking package and the NRC is

seeking further public input on them.

1. Can the new rule and its

implementation yield an equivalent

level of, or would it only have a

marginal impact on, safety?

The present study analyzed risks to

the population and to workers from

changes in appendix J requirements.

The results of the present analysis

confirm that population risks from

severe reactor accidents are not

sensitive to containment leak-rates. The

calculated risks are well below the

Safety Goals for all of the reactors

considered even at assumed

containment leak-rates 100-fold above

current requirements. A change in the

allowable leak-rate is estimated to have

a negligible impact on occupational

exposure. Results also show that

relaxing the frequency of Type A, B, and

C tests leads to an increase in overall

reactor risk of approximately two

percent. This increase is considered to

be marginal to safety. Due to limitations

of available plant data, the uncertainties

of the risk impact of extending Type C

test intervals beyond sixty months

needs to be addressed.

Costs associated with complying with

current appendix J requirements are

estimated to be $165,000 for a complete

battery of Type B/C tests, and

$1,890,000 for Type A tests. Over the

average remaining lifetime of 20 years,

the present value of all remaining leak

testing is about $7 million per reactor at

a five percent discount rate. The

estimates of remaining industry-wide

costs to comply with the requirements

of the current appendix J are

approximately $720 to $1,080 million at

a five percent discount rate, over 75

percent of which could be averted with

a risk-based rule.

Based on the results of the present

study, the NRC concludes that its safety

objective for containment integrity can

be maintained while at the same time

reducing the burden on licensees. Thus,

the new rule and its implementation can

yield an equivalent level of, or only

have a marginal impact on, safety.
Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules 9641

2. Can the regulatory/safety objective

(qualitative or quantitative) be

established in an objective manner to

allow a common understanding between

licensees and the NRC on how the

performance or results will be measured

or judged?

Conformance to the new appendix J

requirements will be measured by the

adequacy of the methods for

establishing the frequency of Type A, B

and C testing. It is a fundamental

principle of this rulemaking that

changes to existing leak-test

requirements be based objectively upon

the performance history of components

as analyzed by established methods.

To assist in the common

understanding of new methods of

establishing Type A, B and C test

frequencies between the NRC and power

reactor licensees, the NRC has had

ongoing discussions with licensees.

These discussions included

participation in workshops designed to

elicit a common understanding. From

these efforts, the NRC is proposing to

endorse a guidance document from

industry which specifies acceptable

methods for achieving compliance with

Appendix J.

Further, the NRC proposes to require

that plant technical specifications

provide a general reference to the

regulatory guide or other

implementation document to ensure the

prior review and approval by the NRC

of licensee deviations from approved

methods. This will help maintain a

common understanding in the

implementation of the performancebased rule, and ensure adequate basis

for licensee deviations.

The NRC expects that its activities to

date, the review and endorsement of a

industry guideline in a regulatory guide,

and the general reference of the

regulatory guide in plant technical

specifications, will establish regulatory

safety objectives in an objective manner,

and provide a common understanding

on the measures of compliance.

3. Can the regulation and

implementation documents be

developed in such a manner that they

can be objectively and consistently

inspected and enforced against?

A guidance document developed by

industry and approved for use by the

NRC helps to ensure consistent

interpretation and application of

compliance requirements. As

experience is gained under the new

rule, adjustments may be reasonably

anticipated to the industry’s guidance

document which will be reviewed and

approved by the NRC through the

regulatory guide revision process. The

NRC’s regulatory and inspection

personnel shall be trained in the

interpretation and use of all relevant

implementation documents to assure

consistent enforcement.

In addition to the above, the NRC

solicits comments on the following two

issues.

4. Should the proposed revision be

made even less prescriptive?

The proposed rule is less prescriptive

than existing requirements and provides

licensees with greater flexibility in the

implementation of safety objectives

established by NRC. This action is

proposed based on substantive technical

analyses presented in draft NUREG–

1493. Regulatory positions were

developed by the NRC through insights

from probabilistic risk analyses,

operating data, and deterministic

engineering considerations. The NRC

solicits public comment on whether this

revision should make the rule even less

prescriptive than proposed in this

notice; and if so, how?

Specifically, comments are solicited

on the potential alternative of further

relaxing the test frequency requirements

for the Integrated Leak Rate Tests (ILRT)

by establishing a fixed ten-year interval

based on generic industry data, or

perhaps eliminating the tests beyond the

first pre-operational test. Analyses of

historical test data and risk analyses

presented in draft NUREG–1493

indicate that the ILRT interval could be

extended beyond the proposed ten-year

interval, and perhaps eliminated after

the first pre-operational test with

marginal impact on safety. Leakages

detected by an ILRT are rare and

random, and not generally related to

previous performance at a plant.

However, the NRC considers that a tenyear testing interval, based on

satisfactory previous plant-specific

performance, is appropriate at this time.

It is consistent with current industry

practice for testing of pressure vessels,

and should detect the potential for aging

mechanisms that could affect

containment leaktightness. Historical

test data have not yet shown evidence

of such aging mechanisms but they

might develop late in life where little

data exists. Comments are solicited on

other benefits provided by the ILRT, in

addition to determining the leakage rate,

that would need to be addressed to

justify further relaxations or elimination

of the test. NRC’s current position is

guided by the desire to maintain some

conservatism to address uncertainties

and adopt an evolutionary approach in

the modification of its requirements.

However, the NRC does not wish to

maintain undue conservatism in its

regulations, and therefore, will consider

comments received to determine the

degree of prescriptiveness, and any

further relaxation of the ILRT

requirements included in the final rule.

5. Should the proposed revisions be

made mandatory?

The NRC is considering whether the

proposed rule, which as currently

proposed would provide licensees with

a non-mandatory alternative to their

existing appendix J containment leak

testing program, should instead be

adopted as a mandatory requirement for

all licensees.

The proposed rule is drafted as a nonmandatory alternative to current

appendix J requirements because the

Staff recognized that some licensees

may have technical programs which

they may not wish to modify at this

time, even though a proposed

modification would constitute a

‘‘relaxation’’ from current requirements

or provide other regulatory or economic

benefit. For these reasons, the

Commission earlier approved a Staff

policy whereby any proposed revisions

to existing NRC requirements developed

by the Regulatory Improvement Program

(See SECY–94–090, ‘‘Institutionalization

of Continuing Program for Regulatory

Improvement,’’ March 31, 1994) would

not be mandatory, but would be

proposed as alternatives (options) to

existing requirements which may be

voluntarily adopted by licensees. Given

the history of difficulty and low success

rate for attempts to resolve new safety

issues simultaneously with

improvements to regulatory efficiency,

the Commission also approved a Staff

policy for separating regulatory actions

for new safety issues from those for

improving regulatory efficiency.

Therefore, this proposed rule does not

address any new safety issues beyond

the scope of the current appendix J

requirements and is not aimed at

improving safety.

The NRC is interested in the public’s

view as to whether the proposed rule

should be made mandatory, in light of

the overall long-term reduction in

regulatory burden on licensees and the

marginal impact on safety which would

be entailed in the relaxation (see

previous discussion in ‘‘Proposed

Modification of Type A, B, C Test

Intervals). The NRC is interested in the

public’s views on using the increase in

regulatory efficiency as a potential

rationale for making the proposed rule

mandatory for all licensees. The NRC

also requests public comment on the

underlying policy discussed above that

NRC rulemakings which are not

intended to increase safety, but are only

intended to increase regulatory

efficiency and reduce the regulatory

burden imposed by the NRC’s rules,
9642 Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules

5The Backfit Rule was subsequently amended in

1988 (53 FR 20603, June 6, 1988) in response to a

decision of the U.S. Court of Appeals for the D.C.

Circuit Union of Concerned Scientists et al. v. U.S.

Nuclear Regulatory Commission, 824 F.2d 103)

which remanded the 1985 rule to the NRC because

the rule failed to clearly indicate that costs may not

be a consideration in determining whether there is

adequate protection to the public health and safety.

should be adopted as alternatives to

existing requirements which may be

voluntarily adopted by the regulated

entity.

The NRC recognizes that if the

proposed rule were made mandatory,

that several backfitting issues are raised.

These backfitting concerns are

discussed in more detail in the next

section on the ‘‘Backfit Rule.’’

Backfit Rule

As discussed above, the Commission

is considering whether the proposed

rule, which is currently drafted as

providing licensees with a nonmandatory alternative relaxing the

requirements for and frequency of

containment leakage testing, should be

adopted as a mandatory requirement

(that is, the requirements of the rule

would be imposed on all nuclear power

plant licensees). If the alternative is

made mandatory, the Commission

acknowledges the potential relevance of

the Backfit Rule. The Commission

believes that the Backfit Rule was

intended to constrain the Commission’s

adoption of mandatory relaxations of

Commission requirements, if the

mandated change imposed costs upon

the licensee and that such mandatory

relaxations are ‘‘backfits’’ as defined in

§ 50.109(a)(1). However, the

Commission believes that it has the

authority and basis for ‘‘waiving’’ the

application of the Backfit Rule to the

adoption of this rulemaking. The

Commission requests public comments

on each of these points.

1. The Proposed Rule Constitutes a

‘‘Backfit’’

The current version of the Backfit

Rule, 10 CFR 50.109, was adopted in

substantially its current form in 1985.5

50 FR 38097 (September 20, 1985).

Based upon a review of the rulemaking

record which led to the final 1985 rule,

the Commission’s objective in adopting

the Backfit Rule was to prevent the

imposition of new requirements, not

otherwise needed to assure adequate

protection or compliance, which were of

marginal overall safety benefit or

involved implementation costs which

were out of proportion to the safety

benefits. The SOC explained that under

the new backfitting standard ‘‘the

Commission would not ordinarily

expect that safety improvements would

be required as backfits which result in

an insignificant or small benefit to the

public health and safety or common

defense and security, regardless of the

implementation costs’’ (50 FR at 38102).

Thus, the aim of the Backfit Rule was to

instill into the regulatory process the

need for disciplined analysis of

proposed new requirements and

regulatory initiatives (See generally 50

FR at 38101–38102).

The proposed revision relaxes and

modifies existing requirements where

the Commission believes that the

burdens are not commensurate with

their safety significance. Furthermore,

the proposed rule does not contain any

new requirements to address new safety

issues not addressed in the original

Appendix J rulemaking. However, if

imposed as a mandatory requirement

the proposed rule would mandate

changes in a licensee’s program for

conducting containment leak rate tests,

and would impose short-term costs on

the licensee in order to reduce the longterm regulatory burden. However

desirable such an imposition may be

over the long term, it would nonetheless

constitute a ‘‘backfit’’ as defined in

§ 50.109(a)(1). However, the

Commission requests public comment

on whether the definition of ‘‘backfit’’ in

§ 50.109(a)(1) was intended to

encompass rulemakings of the type

represented by this proposed rule.

2. Waiving the Applicability of the

Backfit Rule

The Commission adopted the Backfit

Rule as a self-imposed limitation on its

rulemaking authority, and under the

appropriate circumstances the

Commission may ‘‘waive’’ its

applicability, subject to the

Administrative Procedure Act’s

requirement in rulemaking for notice

and opportunity for public comment.

The Commission believes that it is

appropriate to ‘‘waive’’ the applicability

of the Backfit Rule to the proposed rule

if its requirements were made

mandatory. The purpose of the rule is to

relax and modify existing containment

leak rate testing requirements where

burdens are not commensurate with

their safety significance. It does not

contain any new requirements to

address new safety issues not addressed

in the original appendix J rulemaking.

The proposed revision would relax

existing marginal-to-safety requirements

in order to reduce regulatory burden on

nuclear power plant licensees and

increase regulatory efficiency. This type

of rulemaking complements the

objectives of the Backfit Rule by

eliminating requirements with little or

no positive impact on safety, but whose

regulatory burden is substantial.

Therefore, if the Commission

determines to impose the proposed

rule’s requirements, the Commission

proposes to ‘‘waive’’ this rule from the

requirements of the Backfit Rule.

The Commission requests public

comment on the proposed rationale for

‘‘waiving’’ the application of the Backfit

Rule to this rulemaking.

Regulatory Guide; Issuance,

Availability

A draft regulatory guide, temporarily

identified by its task number DG–1037,

(on the same subject) ‘‘PerformanceBased Containment Leak-Test Program’’

is also being published for comment.

The regulatory guide endorses an

industry standard which contains

guidance on an acceptable performancebased leak-test program, leakage rate test

methods, procedures, and analyses that

may be used to implement these

requirements and criteria.

This draft guide is being issued to

involve the public in the early stages of

the development of a regulatory position

in this area. It has not received complete

staff review and does not represent an

official NRC staff position.

Public comments are being solicited

on the draft guide. Comments should be

accompanied by supporting data.

Specific comments are solicited on

whether the regulatory guide and the

industry guideline it endorses will

result in a common understanding

between licensees and the NRC on how

performance will be measured and

judged, and can be objectively inspected

against. Written comments may be

submitted to the Rules Review and

Directives Branch, Division of Freedom

of Information and Publications

Services, Office of Administration, U.S.

Nuclear Regulatory Commission,

Washington, DC 20555. Comments will

be most helpful if received by May 8,

1995. Comments on the draft regulatory

guide may be submitted electronically

as indicated elsewhere under the

ADDRESSES heading.

Although a time limit is given for

comments on these drafts, comments

and suggestions in connection with (1)

items for inclusion in guides currently

being developed or (2) improvements in

all published guides are encouraged at

any time.

Regulatory guides are available for

inspection at the Commission’s Public

Document Room, 2120 L Street NW.,

Washington, DC. Requests for single

copies of draft guides (which may be

reproduced and are available free to the

extent of supply) or for placement on an

automatic distribution list for single

copies of future draft guides in specific
Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules 9643

6Copies may be purchased at current rates from

the Superintendent of Documents, U. S.

Government Printing Office, Mail Stop SSOP,

Washington, DC 20402–9328 (telephone 202 512–

2249 or 202 512–2171); or from the National

Technical Information Service by writing NTIS at

Port Royal Road, Springfield, VA 22161.

divisions should be made in writing to

the Office of Administration, Printing

and Mail Services Section, U.S. Nuclear

Regulatory Commission, Washington,

DC 20555–0001. Telephone requests

cannot be accommodated. Regulatory

guides are not copyrighted, and

Commission approval is not required to

reproduce them. The draft regulatory

guide may also be viewed and

downloaded electronically via the

Electronic Bulletin Board established by

NRC for this rulemaking.

Implementation

The proposed Option B to Appendix

J specifies that the rule will become

effective 30 days after publication. At

any time thereafter, a licensee or

applicant would notify the NRC of its

desire to perform containment leakage

rate testing according to Option B.

Accompanying this notification, a

licensee would submit proposed

technical specifications changes which

would eliminate those technical

specifications which implement the

current rule and propose a new

technical specification referencing the

NRC regulatory guide or, if the licensee

desires, an alternative implementation

guidance. Implementation must await

staff review and approval of the

licensee’s proposal. The staff anticipates

that a generic communication will be

issued which will provide the

implementation procedure to all power

reactor licensees.

Solicitation of Comments for Future

Revisions

As indicated earlier in this notice, the

NRC plans a second phase of

modifications to requirements for

containment leakage rate testing to

further adopt risk-based methods, and to

broadly examine the type of

performance-based rule needed to

ensure the adequacy of the containment

function. This will include increasing

the allowable leakage rate based on risk

considerations, further examination of

the risk significance of various attributes

of containment performance (structural

and leaktight integrity of containment

structures and components, and

inadvertent bypass), and consideration

of the potential of on-line monitoring of

containment integrity to address certain

attributes. In order to guide this future

effort, the NRC has formulated the

following questions and solicits public

comments on them:

1. Should NRC pursue a fundamental

modification of its regulations in this

area by establishing an allowable

leakage rate based on risk analysis (as

presented in draft NUREG–1493,

Chapter 5), as compared to the current

practice of using deterministic design

basis accidents and dose guidelines

contained in 10 CFR part 100; or should

the NRC modify the allowable leakage

rate within the current licensing basis

by revising source terms and updating

regulatory guides (R.G.s 1.3 and 1.4) 6

for calculating doses to the public?

What are the advantages and

disadvantages of the two approaches?

What are some other considerations

than risk to public, e.g. plant control

room habitability, that might limit the

allowable leakage rate?

2. If the allowable leakage rate is

increased, could on-line monitoring of

containment integrity replace other

current containment tests? Could the

results of the on-line monitoring be used

to establish a new performance basis for

containment integrity involving less

stringent reporting requirements if there

is high assurance there are no large

leakage paths in containment (> 1 in.

diameter).

3. Are there any other regulatory

approaches and technical methods by

which the NRC can adopt a complete

performance and risk basis to its

regulations for containment leaktight

integrity? What are some of the

attributes for performance, and what

risk-based methods can be used to

analyze these attributes?

Finding of No Significant

Environmental Impact: Availability

The Commission has determined

under the National Environmental

Policy Act of 1969, as amended, and the

Commission’s regulations in subpart A

of 10 CFR part 51, that this rule, if

adopted, would not be a major Federal

action significantly affecting the quality

of the human environment, and

therefore an environmental impact

statement is not required. There will be

no radiological environmental impact

offsite, and the occupational exposure

onsite is expected to decrease by about

0.8 person rem per year of plant

operation for plant personnel if

licensees adopt the performance-based

testing scheme provided in the revised

regulation. Alternatives to issuing this

revision of the regulation were

considered and found not acceptable.

Single copies of the environmental

assessment and finding of no significant

impact can be obtained by submitting a

written request to: Dr. Moni Dey, U.S.

Nuclear Regulatory Commission,

Washington, DC 20555.

Paperwork Reduction Act Statement

This proposed rule amends

information collection requirements that

are subject to the Paperwork Reduction

Act of 1980 (44 U.S.C. 3501 et seq.).

This rule has been submitted to the

Office of Management and Budget for

review and approval of the paperwork

requirements.

Because the rule will relax existing

information collection requirements by

providing an option to the existing

requirements, the public burden for this

collection of information is expected to

be reduced by as much as 4583 hours

per year, including the time required for

reviewing instructions, searching

existing data sources, gathering and

maintaining the data needed and

completing and reviewing the collection

of information. Send comments

regarding the estimated burden

reduction or any other aspect of this

collection of information to the

Information and Records Management

Branch, T–6F33, U.S. Nuclear

Regulatory Commission, Washington,

DC 20555–0001; and to the Desk Officer,

Office of Information and Regulatory

Affairs, NEOB–10202, (3150–0011),

Office of Management and Budget,

Washington, DC 20503.

Regulatory Analysis

The Commission has prepared a draft

regulatory analysis on this proposed

regulation. The analysis examines the

costs and benefits of the alternatives

considered by the Commission. The

draft analysis is available for inspection

or copying for a fee in the NRC Public

Document Room, 2120 L Street NW

(Lower Level), Washington, DC; the

PDR’s mailing address is Mail Stop LL–

6, Washington, DC 20555; phone (202)

634–3273; fax (202) 634–3343.

The Commission requests public

comment on the draft analysis.

Comments on the draft analysis may be

submitted to the NRC as indicated

under the ADDRESSES heading.

Regulatory Flexibility Certification

In accordance with the Regulatory

Flexibility Act of 1980, (5 U.S.C.

605(b)), the Commission certifies that

this rule will not, if promulgated, have

a significant economic impact on a

substantial number of small entities.

This proposed rule affects only the

licensing and operation of nuclear

power plants. The companies that own

these plants do not fall within the scope

of the definition of ‘‘small entities’’ set

forth in the Regulatory Flexibility Act or

the Small Business Size Standards set
9644 Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules

7Specific guidance concerning a performancebased leak test program, acceptable leakage rate test

methods, procedures, and analyses that may be

used to implement these requirements and criteria

are provided in draft Regulatory Guide DG–1037,

‘‘Performance-Based Containment System Leakage

Testing.’’

out in regulations issued by the Small

Business Administration in 13 CFR part

121.

Backfit Analysis

This proposed revision to a current

regulation by the inclusion of an option

that may be voluntarily adopted by

licensees, and which relaxes current

requirements, is not considered a backfit

under 10 CFR 50.109(a). Therefore, a

backfit analysis is not necessary.

List of Subjects in 10 CFR Part 50

Antitrust, Classified information,

Criminal penalties, Fire protection,

Incorporation by reference,

Intergovernmental relations, Nuclear

power plants and reactors, Radiation

protection, Reactor siting criteria,

Reporting and recordkeeping

requirements.

For the reasons set out in the

preamble and under the authority of the

Atomic Energy Act of 1954, as amended,

the Energy Reorganization Act of 1974,

as amended, and 5 U.S.C. 553, the NRC

is proposing to adopt the following

amendments to 10 CFR part 50.

PART 50—DOMESTIC LICENSING OF

PRODUCTION AND UTILIZATION

FACILITIES

1. The authority citation for Part 50 is

revised to read as follows:

Authority: Secs. 102, 103, 104, 105, 161,

182, 183, 186, 189, 68 Stat. 936, 937, 938,

948, 953, 954, 955, 956, as amended, sec.

234, 83 Stat. 1244, as amended (42 U.S.C.

2132, 2133, 2134, 2135, 2201, 2232, 2233,

2236, 2239, 2282); secs. 201, as amended,

202, 206, 88 Stat. 1242, as amended, 1244

1246 (42 U.S.C. 5841, 5842, 5846).

Section 50.7 also issued under Pub. L. 95–

601, sec. 10, 92 Stat. 2951, as amended by

Pub. L. 102–486, sec. 2902, 106 Stat. 3123,

(42 U.S.C. 5851). Sections 50.10 also issued

under secs. 101, 185, 68 Stat. 936, 955, as

amended (42 U.S.C. 2131, 2235); sec. 102,

Pub. L. 91–190, 83 Stat. 853 (42 U.S.C. 4332).

Sections 50.13, 50.54(dd), and 50.103 also

issued under sec. 108, 68 Stat. 939, as

amended (42 U.S.C. 2138). Sections 50.23,

50.35, 50.55, and 50.56 also issued under sec.

185, 68 Stat. 955 (42 U.S.C. 2235). Sections

50.33a, 50.55a and Appendix Q also issued

under sec. 102, Pub. L. 91–190, 83 Stat. 853

(42 U.S.C. 4332). Sections 50.34 and 50.54

also issued under sec. 204, 88 Stat. 1245 (42

U.S.C. 5844). Sections 50.58, 50.91, and

50.92 also issued under Pub. L. 97–415, 96

Stat. 2073 (42 U.S.C. 2239). Section 50.78

also issued under sec. 122, 68 Stat. 939 (42

U.S.C. 2152). Sections 50.80–50.81 also

issued under sec. 184, 68 Stat. 954, as

amended (42 U.S.C. 2234). Appendix F also

issued under sec. 187, 68 Stat. 955 (42 U.S.C.

2237).

2. Appendix J to 10 CFR Part 50 is

amended by adding the following

language between the heading and the

Table of Contents and adding the

language for Option B after Section

V.B3.

Appendix J—Primary Reactor

Containment Leakage Testing for

Water-Cooled Power Reactors.

This appendix includes two options, A and

B, either of which can be chosen for meeting

the requirements of this appendix.

Options A—Prescriptive Requirements

* * * * *

Option B—Performance-Based Requirements

Table of Contents

I. Introduction.

II. Definitions.

III. Performance-based leakage test

requirements.

A. Type A test.

B. Type B and C tests.

IV. Recordkeeping.

V. Implementation.

I. Introduction

One of the conditions required of all

operating licenses for light-water-cooled

power reactors as specified in § 50.54(o) is

that primary reactor containments meet the

leakage rate test requirements in either

Option A or B of this appendix. These test

requirements ensure that (a) leakage through

these containments or systems and

components penetrating these containments

does not exceed allowable leakage rates

specified in the Technical Specifications and

(b) integrity of the containment structure is

maintained during its service life. Option B

of this appendix identifies the performancebased requirements and acceptance criteria

for preoperational and subsequent periodic

leakage rate testing.7

II. Definitions

Acceptance criteria means the performance

standards against which test results are to be

compared for establishing the acceptability of

the containment system as a leakage limiting

boundary.

Containment system means the principal

barrier, after the reactor coolant pressure

boundary, to prevent the release of quantities

of radioactive material that would have a

significant radiological effect on the health of

the public.

Overall integrated leakage rate means the

total leakage rate through all tested leakage

paths, including containment welds, valves,

fittings, and components that penetrate the

containment system.

La (percent/24 hours) means the maximum

allowable leakage rate at pressure Pa as

specified in the Technical Specifications.

Pa (p.s.i.g) means the calculated peak

containment internal pressure related to the

design basis loss-of-coolant accident as

specified in the Technical Specifications.

III. Performance-Based Leakage Test

Requirements

A. Type A Test

Type A tests to measure the containment

system overall integrated leakage rate must

be conducted under conditions representing

design basis loss-of-coolant accident

containment peak pressure. A Type A test

must be conducted (1) after the containment

system has been completed and is ready for

operation and (2) at a periodic interval based

on the historical performance of the overall

containment system as a barrier to fission

product releases to reduce the risk from

reactor accidents. A general visual inspection

of the accessible interior and exterior

surfaces of the containment system for

structural deterioration which may affect the

containment leaktight integrity must be

conducted prior to each test, and at a

periodic interval between tests based on the

performance of the containment system. The

leakage rate must not exceed the allowable

leakage rate (La) with margin as specified in

the Technical Specifications. The test results

must be compared with previous results to

examine the performance history of the

overall containment system to limit leakage.

B. Type B and C Tests

Type B pneumatic tests to detect and

measure local leakage rates across pressure

retaining, leakage limiting boundaries, and

Type C pneumatic tests to measure

containment isolation valve leakage rates,

must be conducted (a) prior to initial

criticality, and (b) periodically thereafter at

intervals based on the safety significance and

historical performance of each boundary and

isolation valve to ensure the integrity of the

overall containment system as a barrier to

fission product release to reduce the risk

from reactor accidents. The performancebased testing program must contain

performance goals and acceptance criteria,

consideration of factors that affect

performance when establishing test intervals,

evaluations of performance of containment

system components, and comparison to

previous test results to examine the

performance history of the overall

containment system to limit leakage. The

tests must demonstrate that (1) the sum of the

leakage rates at accident pressure of Type B

tests, and pathway leakage rates from Type

C tests, is less than the total allowable

leakage rate (La) specified in the Technical

Specification with margin; and (2) the

performance goal for the reliability of the

overall containment system to limit leakage

during reactor accidents is not exceeded.

IV. Recordkeeping

The results of the preoperational and

periodic Type A, B, and C tests must be

documented to show that acceptance criteria

for leakage have been met. The comparison

to previous results of the performance of the

overall containment system and of individual

components within it must be documented to

show that the test intervals established for

the containment system and components

within it are adequate. These records must be

available for inspection at plant sites.

If any Type A, B, or C tests fail to meet

their leakage rate acceptance criteria as
Federal Register / Vol. 60, No. 34 / Tuesday, February 21, 1995 / Proposed Rules 9645

defined in the plant Technical Specifications

those failures must be assessed for

Emergency Notification System reporting

under §§ 50.72(b)(1)(ii) and 50.72(b)(2)(i),

and for a Licensee Event Report under

§§ 50.73(a)(2)(ii).

V. Implementation

A. Applicability

The requirements in either or both Option

B, III.A for Type A tests, and Option B, III.B

for Type B and C tests, may be adopted on

a voluntary basis by an operating nuclear

power reactor licensee as specified in § 50.54

in substitution of the requirements for those

tests contained in Option A of this appendix.

If the requirements for tests in Option B, III.A

or Option B, III.B are implemented, the

recordkeeping requirements in Option B, IV

for these tests must be substituted for the

reporting requirements of these tests

contained in Option A of this appendix.

B. Effective Date

1. Specific exemptions to Option A of this

appendix that have been formally approved

by the AEC or NRC, according to 10 CFR

50.12, are still applicable to Option B of this

appendix if necessary, unless specifically

revoked by the NRC.

2. This amendment to this appendix, by

inclusion of an additional option for meeting

the requirements of the appendix, is effective

(30 days after the publication of the final

rule). At any time hereafter a licensee or

applicant for an operating license can adopt

Option B, or parts thereof, as specified in

Section V.A of this appendix, by submitting

a notification of its implementation plan and

request for revision to technical

specifications to the Director of the Office of

Nuclear Reactor Regulation.

The regulatory guide or other

implementation document used by a

licensee, or applicant for an operating

license, to develop a performance-based

leakage testing program must be included, by

general reference, in the plant’s technical

specifications. The detailed licensee

programs must be available at the plant site

for inspection thereafter. The programs must

contain justification, including supporting

analyses, if they deviate from methods

approved by the Commission and endorsed

in a regulatory guide. The deviations and

their justifications must be described in the

notification provided by the licensee of its

implementation plan and the submittal for

revision of plant technical specifications.

Dated at Rockville, MD, this 14th day of

February, 1995.

For the Nuclear Regulatory Commission.

John C. Hoyle,

Acting Secretary of the Commission.

[FR Doc. 95–4167 Filed 2–17–95; 8:45 am]

BILLING CODE 7590–01–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94–NM–120–AD]

Airworthiness Directives; Boeing

Model 747SP Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Supplemental notice of

proposed rulemaking; reopening of

comment period.

SUMMARY: This document revises an

earlier proposed airworthiness directive

(AD), applicable to certain Boeing

Model 747SP series airplanes, that

would have superseded an existing AD

to require inspections to detect cracks in

the web of the wing front spar, and

modification, if necessary. That

proposal was prompted by a report of

cracking in the web in an area outside

the inspection zone specified in the

existing AD. A crack in the web that is

not detected before it extends outside

the chord footprints can allow fuel

leakage. This action revises the

proposed rule by reducing the

compliance time for inspections of

certain airplanes. The actions specified

by this proposed AD are intended to

prevent fuel leakage onto an engine and

a resultant fire due to cracking in the

web of the wing front spar.

DATES: Comments must be received by

March 7, 1995.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 94–NM–

120–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Comments may be inspected at this

location between 9:00 a.m. and 3:00

p.m., Monday through Friday, except

Federal holidays.

The service information referenced in

the proposed rule may be obtained from

Boeing Commercial Airplane Group,

P.O. Box 3707, Seattle, Washington

98124–2207. This information may be

examined at the FAA, Transport

Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Tim

Backman, Aerospace Engineer, Airframe

Branch, ANM–120S, FAA, Transport

Airplane Directorate, Seattle Aircraft

Certification Office, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056;

telephone (206) 227–2776; fax (206)

227–1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to

participate in the making of the

proposed rule by submitting such

written data, views, or arguments as

they may desire. Communications shall

identify the Rules Docket number and

be submitted in triplicate to the address

specified above. All communications

received on or before the closing date

for comments, specified above, will be

considered before taking action on the

proposed rule. The proposals contained

in this notice may be changed in light

of the comments received.

Comments are specifically invited on

the overall regulatory, economic,

environmental, and energy aspects of

the proposed rule. All comments

submitted will be available, both before

and after the closing date for comments,

in the Rules Docket for examination by

interested persons. A report

summarizing each FAA-public contact

concerned with the substance of this

proposal will be filed in the Rules

Docket.

Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to this notice

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 94–NM–120–AD.’’ The

postcard will be date stamped and

returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this

NPRM by submitting a request to the

FAA, Transport Airplane Directorate,

ANM–103, Attention: Rules Docket No.

94–NM–120–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

A proposal to amend part 39 of the

Federal Aviation Regulations (14 CFR

part 39) to add an airworthiness

directive (AD), applicable to certain

Boeing Model 747SP series airplanes,

was published as a notice of proposed

rulemaking (NPRM) in the Federal

Register on October 28, 1994 (59 FR

54134). That NPRM would have

superseded an existing AD to require

repetitive inspections to detect cracks in

the web of the wing front spar over

engine numbers 2 and 3, and repair, if

necessary. That NPRM was prompted by

a report of cracking in the web in an

area outside the inspection zone

specified in the existing AD. That

condition, if not corrected, could result

in fuel leakage onto an engine and a

resultant fire.