ML20056C356

Forwards Ssar Markups Addressing Questions Raised at 930511 Ge/Nrc Conference Call Re Subsection 3.5.1.1, Internally Generated Missiles (Outside Containment)

ML20056C356
Person / Time
Site:	05200001
Issue date:	05/14/1993
From:	Fox J GENERAL ELECTRIC CO.
To:	Poslusny C Office of Nuclear Reactor Regulation
References
NUDOCS 9305200028
Download: ML20056C356 (5)

Text

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. GE Nuclear Energy

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May 14,1993 Docket No. STN 52-001

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l Chet Poslusny, Senior Project Manager i Standardization Project Directorate l

Associate Directorate for Advanced Reactors and License Renewal Office of the Nuclear Reactor Regulation

Subject:

Submittal Supporting Accelerated ABWR Review Schedule - Clarification of j SSAR Subsection 3.5.1.1

Dear Chet:

Enclosed are SSAR markups addressing the questions raised at the May 11,1993 GE/NRC conference call pertaining to Subsection 3.5.1.1, Internally-Generated Missiles (Outside Containment).

Please provide a copy of this transmittal to Butch Burton. i Sincerely, l

Y Jack Fox Advanced Reactor Programs cc- Gary Ehlert (GE) ,

Norman Fletcher (DOE) l h

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.y Criterion 4 of 10CFR50 Appendix A, General l 3.5 MISSILEPROTECTION l

Design Criteria for Nuclear Power Plants.

The missile protection design basis for l Seismic Category I structures, systems and Potential missiles that have been identified l components is described in this section. A are listed and discussed in later subsections.

l tabulation of safety related structures, systems,

! and components (both inside and outside After a potential missile has been containment), their location, seismic category, identified, its statistical significance is l

and quality group classification is given in determined. A statistically significant missile Table 3.2-1. General arrangement drawings is defined as a missile which could cause showing locations of the structures, systems, and unacceptable plant consequences or violation of components are presented in Section 1.2. the guidelines of 10CFR100.

l Missiles considered are those that could The examination of potential missiles and i l

result from a plant-related failure or incident their consequences is done in the follcwing including failures within and outside of manner to determine statistically significant l containment, erwironmental-generated missiles and missiles:

site-proximity missiles. The structures, shields, and barriers that have been designed to (1) If the probability of occurrence of the ,

withstand missile effects, the possible missile missfle (P3 ) is determined to be less than l

loadings, and the procedures to which each 10' per year, the missile is dismissed l l

barrier has been designed to resist missile from further consideration because it is impact are described in detail. considered not to be statistically si g nifi c a n t. )

3.5.1 Missile Selection and Description (2) If (P 3) is found to be greater than 10 l

per year, it is examined for its probability Components and equipment are designed to have of impacting a design target (P.,).

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• l a low potential for generation of missiles as a

basic safety precaution. In general, the design (3) If the productj of (P3 ) and (P2 ) I' I*

1 that results in reduction of missile-generation than 10 per year, the missile is l

potential promotes the long life and usability of dismissed from further consideration.

a component and is well within permissible limits of accepted codes and standards. (4) If the product of (P ) and (P.,) is 3

greater than 10'7 per year, the misiile is l Seismic Category I structures have been examined for its damage probability (P3). l analyzed and designed to be protected against a If the combined probability (i.e.7P3 x wide spectrum of missiles. For example, failure P2 xP = P4) is less than 10' per of certain rotating or pressurized components of year, tfie missile is dismissed.

l equipment is considered to be of sufficiently high probability and to presumably lead to (5) Finally, measures are taken to design generation of missiles. However, the generation acceptabic protection against missiles with of missiles from other equipment is considered to (P,) greater than 10'# per year to be of low enough probability and is dismissed reduce (P,), (Py ), and/or (P ), so from further consideration. Tornado-generated that (P4) is less than 10'j per 3year.

missiles and' missiles resulting from activities so4 %- releAe ci -

particular to the site are also discussed in this Protection of-enential-structures, systems section. The missile protection criteria to and components is afforced by one or more of the which the plant has been analyzed comply with following practices-351 Amendment 3

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(1) Location of the system or component in an (6) Automatic depressurization system relief f valves; .l individual missile-proof structure; i

(2) Physical separation of redundant systems or (7) Standby diesel generator system; l

i components of the system for the missile CRD scram system (hydraulic and trajectory path or calculated range; (8) l electrical); -

(3) Provision of localized protection shields or i barriers for systems or components; (9) Fuelpoolcoohng and cleanup system; (4) Design of the particular structure or (10) Remote shutdown pancl; j component to withstand the impact of the ,

most damaging missile; (11) Reactor protection system; J i

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(5) Provision of design features on the (12) All containment isolation valves; l

! potential missile source to prevent missile gencration; and/or (13) HVAC emergency chilled water system; l

(14) HVAC systems required during operation of l (6) Orientation of the potential missile source l to prevent unacceptable consequences due to items (1) through (12); and j 1 missile generation.

(15) Electrical and control systems and wiring l

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The following criteria have been adopted to required for operation of items (1) through l

l l j provide an acceptable design basis for the (14).

1 plant's capability to withstand the statistically The following general criteria are used in ,

, significant missiles reactor building. postulated inside the the design, manufacture, and inspection of  ;

j d equipment: (

I (1) No loss of containment function as a result I of missiles generated internal to (1) All pressurized equipment and sections of

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containment. piping that may periodically become

! isolated under pressure are provided with j pressure relief valves acceptabic under

(2) Reasonable assurance that a safe plant shut-

' down condition can be achieved and ASME Code Section III. The valves ensure

1. that no pressure buildup in equipment or maintained.

piping sections exceeds the design limits (3) Offsite exposure within the 10CFR100 of the materials involved.

j j guidelines for those potential missile damage events resulting in radiation (2) Components and equipment of the various activity release. systems are designed and built to the stan-6.pd -

A dards established by the ASME Code or other

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The systems requiring protection are:

equivalent industrial standard. A strin-l gent quality control program is also en-i forced during manufacture, testing, and in-i (1) Reactor coolant pressure boundary;

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! (2) Residual heat removal system; (3) Volumetric and ultrasonic testing where re-s quired by code coupled with periodic inser-

(3) High pressure core flooder system; vice inspections of materials used in com-ponents and equipment add further assurance j (4) Reactor core isolation cooling system; that any material flaws that could permit j

' the generation of missiles are detected.

(5) Reactor building cooling water system; l

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(4) The failure of nonsafety-related equipment, components, or .

structures whose failure could result in a missile do not

cause the failure of more than one division of safety-related ,

equipment.

l (5) No high energy lines are located near the standby-gas treatment  !

charcoal vaults, the offgas charcoal storage vault. or the spent fuel pool.

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Standard Plant REV.A 3J.1.2.3 Evaluation of Potential Gravitational Missiles Inside Containment Gravitational missiles inside the containment ]

have been considered as follows. ,

Seismic Category I systems, components, and j For local shields and barriers see the response structures are not potential gravitational mis- {

to Question 410.9. site sources. )

l 3.5.1.2 Internally Generated Missiles (Inside Non-Seismic Category I items and systems Containment) inside containment are considered as Follows: l Internal missiles are those resulting from (1) Cable Tray l plant equipment failures within the contain-  !

ment. Potential missile sources from both All cable trays for both Class 1E and non- l rotating equipment and pressurized components are Class IE circuits are seismically supported  !

considered. whether or not a hazard potential is  !

evident. j 3.5.1.2.1 Rotating Equipment (2) Conduit and Non-Safety Pipe By an analysis similar to that in Subsection .

3.5.1.1.1, it is concluded that no items of Non-Class IE conduit is seismically sup-  !

rotating equipment inside the containment have ported if it is identified as a potential j the capability of becoming pr tential missiles. hazard to safety-related equipment. All i All reactor internal pumps are incapable of Nuclear Island non-safety related piping 1 achieving an overspeed condition and the motors that is identified as a potential hazard is and impellers are incapable of escaping the seismically analyzed per Subsection casing and the reactor vessel wall, respectively. 3.7.3.13.

All drywell cooler fans, re designed such (3) . Equipment for Maintenance j that their blades are incapable of leaving the ,

case. All other equipment, such as hoists, that is required during maintenance will either be i 3.5.1.2.2 Pressurized Components removed prior to operation, moved to a '

location where it is not a potential hazard Identification of potential missiles and their to safety- related equipment, or seismically consequences outside containment are specified in restrained to prevent it from becoming a Subsection 3.5.1.1.2. The same conclusions are missile. - See Sub- section 3.5.4.7 for COL drawn for pressurized components inside of con- license information.

talment. For example, the ADS accumulators are moderate energy vessels and are therefore not 3.5.1.3 Turbine Missiles considered a credible missile source. One additional item is fine motion control rod drives See Subsection 3.5.1.1.13.

(FMCRD) under the reactor vessel. The FMCRD mechanisms are not credible missiles. The FMCRD ~ -

housings are designed (Section 4.6) to prevent ,

any significant nuclear transient in the event of a drive housing break.

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I Amendment 3.54 l

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