ML19276G891

Advises of Position Re Reg Guide 1.140,Revision 0, Design, Testing & Maint Criteria for Normal Ventilation Exhaust Air Filtration & Absorption Units of Light Water Cooled Nuclear Power Plants.

ML19276G891
Person / Time
Site:	North Anna
Issue date:	08/24/1979
From:	Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Parr O Office of Nuclear Reactor Regulation
References
RTR-REGGD-01.140, RTR-REGGD-1.140 674, NUDOCS 7908280558
Download: ML19276G891 (4)

Text

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Vepco ___

At.gast 24, 1979-Mr. Hareld R. Denton, Director Serial'No. 674 Office tf Nuclear Reactor Regulation PSE&C/SNK:adw:mc Attn: Mr. 0. D. Parr, Chief Light Kater Reactors Branch No. 3 DdcketNos.50-44 Division cf Project Management 50-405-U. S. Nuclear Washington,. d. C. Regulatory 20555 Commission ,

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Dear Mr. Denton:

Our letter Serial No. iO39 of February 6,1979, adviseo you of our in-tenticn to infcnn you centineally of comoany positions which are not in accordance witn individ;al Regalatory Guides. This latter advises you of the ccmpany position dn. Regulatcry Caide 1.140, Revision 0, " Design, Test-ing, and Maintenance Critarla for Normal Ventilatten Exhaust System Air filtration and Adsorption Units of Light-Water-Cooled Nuclear Power Plants"'

.for the North Anna 3 and 4 units. .

Corpany Position The North Annt Units 3 and 4 project will comply with the Regulatory Position (paragrapn :) of this guide with the followimg clarifications or cxceptfons:

.l.a - The design of each atr.osphere cleanup system is based on air flex rate and resident time. .

c.3.d - Some filters are upstream ac: css c.3.f - Exception is taken to Section 5.10.3.5 of ANSI N509-1976; ductwork, as a structure, will have a resonant frequency above 25 Hz, but this may not be true for the unsup?orteu ^

plate of sheet section.

c.3.1 - System racistances will be detemined in accordance with Section '5.7.1 of AN51 N509-1976 except that fan inlet and outlet losse will not be calculated in accordance with

'AMCA 201.

Exception is taken to Section 5.7.2 of A'4SI N509-1976; copies of fan rntinds or test reports are not ne.cescary when certi'-

fied on performance curves are furqished.

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• 4 5" "o-v.acm eucTaic Ano powen courAsv ro Mr. Harold R. Denton 2 c.2.f The volumetric airflow of a single filter train in the Auxiliary Building is 64,000 scfm as compared to the recomended value of 30,000 scfm. The recomended volumetric airflow rate of 30,000 scfm is based on a train assembly of 3 HEPA filters high by 10 HEPA fil-ters wide (1000 scfm per filter). 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 HEPA filter assemblies and will have no effect on the testing of the filters as set forth by ANSI N510 stan-dard.

c.2.g North Anna 3 and 4 project complies except alarms are not siesmic Category I.

c.2,h The degree of compliance is subject to the regulatory positions on Regulatory Guides 1.32, 1.89, 1.30, 1.100 and 1.118 and IEEE Standards 279 and 334.

c. 2.. i North Anna 3 and 4 project complies. The present common exhaust filter system s provided with automatic activa-tion of the safeguard area ventilation and filtration following a LOCA of the affected unit. The control room filtration system is manually activated by the control room operator following the depletion of compressed air, which is approximately one hour after the accident.

c.2.j The Auxiliary Building common exhaust filtration system cannot be removed as an intact unit because of its length.

The enclosed common exhaust filtration system is designed to be removed as a minimum number of segmented sections.

Individual filter components will be removed prior to cutting the housing into segmented sections. Cutt.ing the ABCEFS into segmented sections for removal with the indivi-dual components intact exposes the local environment and personnel to unnecessary contamination. In order to minimize operator exposure, each :omponent is packed, shield-ed, and shipped after components are removed and handled in-dividually. Removal of the der.ontaminated housing is com-pieted by cutting into a minimum number of sections which can be packaged, shielded and shipped, minimizing the exposure.

c.3.a No demisters are provided.

c.3.f Some filters are upstream access. Also, refer to c.2.f above.

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vinomia sucTaic AND POWER COMPANY TO Mr. Harold R. Denton 3 c.3.g The control room system which is 1,000 cfm is a non-entry unit.

c.3.h Drains are not provided on the control room filters.

c.3.k When conservative calculations show that the maximum decay heat generation from collected radioiodines 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 ANSI N509-1976 except that fan inlet and outlet losses will not be calculated in accordance with AMCA 201.

Exception is taken to Section 5.7.2 of ANSI N509-1976; copies of fan ratings or test reports are not necessary when certified fan perfonnance curves are furnished.

Exception is taken to balancing techniques defined in Section 5.7.3 of ANSI N509-1976. Displacement criteria following normal industry practice will be used when maximum vibration velocity method imposes unrealistic requirements at certain operating speeds.

Documentation will not be furnished in accordance with Section 5.7.5 where AMCA certification ratings are sub-mitted.

c.3.n Exception is taken to Section 5.10.3.5 of ANSI N509-1976; ductwork, as a structure, will have a resonant 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 ANSI N509-1976 of designing dampers to ANSI B31.1 and to using butterfly valves. Class 8 dampers may be designed and tested to meet the verification of strength and leak-tightness necessary for use in a contaminated air stream.

(Note: This exception does not pertain to containment 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.

Minimum diameter of damper shaft length 24 in, and under shall be h in.; and 3/4 in, for shafts between 25 and 48 in.

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VIRGINE EUCTRIC AND POWER COMPANY TO Mr. Harold R. Denton SHEET NO. 4 c.4.a The design of atmosphere cleanup systems minmizes the time that personnel are exposed to contaminated 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 room 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. per month. However, if field data confirms that it is unnecessary to run the trains 10 hr. per month to reduce the amount of moisture present on the filters, this decision will be reconsidered.

This position will be placed on file and will be included in the Final Safety Analysis Report for these units.

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

Very truly yours,

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Sam C. Brown, Jr.

Senior Vice President-Power Station Engineering and Construction 204} lb