ML19209A679

Advises of Nonconformance to Reg Guide 1.52,Revision 2, Design,Testing & Maint Criteria for Post-Accident Engineered Safety Feature Atmosphere Cleanup Sys...Light Water Cooled Nuclear Power Plants. Pages Reordered

ML19209A679
Person / Time
Site:	North Anna
Issue date:	08/24/1979
From:	Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Harold Denton, Parr O Office of Nuclear Reactor Regulation
Shared Package
ML19209A670	List: ML19209A669 ML19209A677 ML19209A679
References
675, 790524-02, 790524-2, NUDOCS 7910050178
Download: ML19209A679 (4)

Text

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August 24, 1979 Mr. Harold R. Denton, Director Sarial No. 675 Office of fluclear Reactor Regulation PSE1C/SNK:cdw:mc Attn: Mr. O. D. Parr, Chief Light Wa:er Reactors Branch flo. 3 Docket Nos. 50-404 ,

, . .

Division of Project Management 50-405 ,

U. S. Nuclear Regulatory Comission Washington, D. C. 20555 Cear Mr. Denton:

Our letter Serial No. 039 of February 6,1979 advised you of our intention to inform you continually of company positions which are not in accordance with individual Regulatory Guides. This letter advises you of the Company position on Regulatory Guide 1.52, Revision 2, "De-sign, Testing, and Maintenance Criteria for Post Accident Engineered-Safety-Feature Atmosphare Cleanup System Air Filtration and Adsorption Units of Light-Watar-Cooled i;uclaar Power Plants", for the North Anna 3 and 4 Units.

Company Position The engineerad-safety-feature ataosphere cleanup system air filtra-tion and adsorption units for florch Anna 3 and 4 are as follows:

a. Auxiliary Building Coman Exhaust Filtration System c.

• Control Rocm Energency Filtration System The North Anna Units 3 and 4 project will comply with the Regulatory Position (paragraph c) of this Guide with the folicwing clarifications or exceptions:

c.1.c The syste.m are designed based on air flow rate and resident time.

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c.2.b Vepco ccmplies for the control room emergency filter sys tem. The comon exhaust filter system is not pro-tected frc:n missiles generated by natural phenomena.

The top floor of Auxiliary Building is not designed for missile protection.

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P00R~0 Mi m Mr. Harold R. Centon 2 c.2.f The volumetric airflow of a single filter train in the Auxiliary Btillding is 64,000 scfn as compared to -  ?

the racc. mended value of 30,000 scfm. The recomended volumetric airficw rata of 30,000 scfm is based on a train assembly of 3 HEPA filtars hign oy 10 HEPA fil-ters wide (1000 scfm per filtar). Vepco's array in the Auxiliary Building is 4 HEPA filters high by 16 HEPA filters wide, or 1000 scfm per filter. Vepco's.=

design is not detrimental to the maintenance of the .!  ;

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HEPA filter assemblies and will have no effect on the testing of the filters as set forth by ANSI N510 stan-dard.

c.2 9 florth Anna 3 and 4 project ccmplies except alarms are not siasmic Category I.

c.2.h Tha cegree of ccepliance is subject to the regulatory positions on Regulatory Guides 1.32, 1.39, 1.30, 1.100 and 1.11d and IEEE Standards 279 and 334, c.2.i tierth Anna 3 and 4 project complies. Tne present comon exha st filter system is provided with automatic activa-tion of the safeguard area ventilation and filtration follcuing a LCCA of the affected unit. The control room filtruicn system is manually activated by the control rect. cparator following tne deplatica of compressed air, which is approximately one ncur af ter the accident.

c.2.j Th e ',cuxiliary Lailcing ccmon exhaust filtration system cannat be removed as an intact t: nit because of its length.

Tne enclosea ccamen exhaust filtration systea is designed to ' c2 removed as a ,ninimum nu.r.ber of segmented sections.

Incividual filter components will be removed prior to cutting the housing into segmantec sections. Cutting the ABCEF5 into segmented secticns fcr removal with the indivi-cual ccmponents intact exposes the local environment and personnel to unnecessary conta.nination. In order to minimize operator exposure, each component is packed, shield-ed, and shipped aftar components are removed and handled in-cividually. P,emoval of the decontaminated housing is ccm-pleted by cutting into a minimum number of sections which can be packaged, shielded and shipped, minimizing the exposure.

c.3.a Go desisters are proviced, c.3.f Some filters are upstream access. Also, refer to c.2.f above.

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fir. Harold R. Canton c.3 9 The control room system which is 1,000 cfm is a non-entry ~*

unit.

c.3.h Drains are nct provided on the control room filters.

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c.3.k When conservative calculations show that the naximum

. decay heat generation frcra collected radiciodines is insufficient to raise the carbon bed temperature above ,

2500F with no system airflow, small capacity ESF -.

atmosphere cleanup systems may be designed without an air bleed cooling mechanism..

c.3.1 System resistances will be determined in accordance with Section 5.7.1 of MSI N509-1976 except that fan inlet and outlet losses will not be calculated in accordance with MCA 201.

Exception is taken to Section 5.7.2 of MlSI il509-1976; copies of fan ratings or test repot ts are not nacessary when certified fan performance curves are furnished.

Exception is taken to balancing techniques defined in Section 5.7.3 of MSI ti509-1976. Displacement criteria following normal industry practice will be used when raximum vibration velocity r.ethod imposes unrealistic requirements at certain operating speeds.

Cocu ,entation will not be furnished in accordance with Sectica 5.7.5 where AMCA certification ratings are sub-mittad.

c.3.n Exception is taken to Section 5.10.3.5 of MSI (1509-1976; ductwork, as a structure, will have a rasonant frequency above 25 Hz, but this may not be true for the unsupported plate of sheet sections.

c.3.p Exception is taken to the provisions of Section 5.9 of MSI N509-1976 of designing dampers to A1SI B31.1 and to .

using butterfly valves. Class 8 dampers may be designed

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and tested to meet the verification of strength and leak-- ,

tightness necessary for use in a contaminated air stream. ,

(flote: This exception does not pertain to contain=ent.

penetrations.)

In addition, exceptions are taken to the following:

Class B leakage rates shall be determined for one damper or each type instead of every damper.

Tilnimum diameter of damper shaft length 24 in, and under shall be 6 in.; and 3/4 in, for shaf ts between 25 and 48 in.

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!'r. Harold P,. Denton 4 c.4.a The d .ign of at:aosphere cleanup systems mincizes '

the time that personnel are exposed ta contaninated components. The guidelines specified in this para-graph are considered to be general guides, and full compliance is not necessary.

c.4.b The dimensions do not allow 3 feet between banks.

Mounting frames in the control roca filters are less -

than three feet apart. All filter assemblies are provided with adequate working space to permit the maintenance personnel to replace the filters.

c.4.d ESF atmosphere cleanup systems are run a minimum of 10 hr. par month. Hcwever, if field data confirms that it is unnecessary to run the trains 10 hr. per month to reduce the amount of noisture present on the filters, this decision will be reconsidered.

This position will be placed en file and will be included in the Final Safety Analysis F.eport for these units.

We would be pleased to discuss this position with you at your conven-iance. Should you wish to meet with us to discuss this position, or if you have any questians please contact us.

Very truly yours,

.Origiral Signed by yl. C. SPENCER San C. Drown, Jr.

Senior Vice President-Power Station Engineering and Construction I

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