ML19343C480
| ML19343C480 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/17/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737 NUDOCS 8103240341 | |
| Download: ML19343C480 (4) | |
Text
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y TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374C1' 400 Chestnut Street Tower II
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March 17, 1981
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~Mr. Harold R. Denton, Director
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.U.S.: Nuclear Regulatory Commission Washington, DC 20555 4
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Dear Mr. Denton:
In the Matter of the
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. Docket Nos. 50-259 Tennessee Valley Authority.
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50-260 50-296 NUREG-0737, Clarification of TMI-Action Plan Requirements, was
' transmitted to TVA by D. G. Eisenhut's letter dated October 31, 1980, to
- All' Licensees of. Operating Plants and Applicants for Operating Licensees and Holders of. Construction Permits.
TV1. provided an initial response on
-December 23, 1980. As required by NUiti:,G-0737, enclosed is our response to item III.D.3.4, Control Room Habitability Requirements, for the Browns Ferry Nuclear Plant.
Very truly.yours, TENNESSEE VALLEY AUTHORITY s
Nuclear Regulation'and Safety
.Subscribey sworn to before~-
me this //_ dt 7. of hdA/I/1981.
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r EMCLOSURE REspO"SE TO D. G. EISE!!!!UT'S LETTER DATED OCTOBER 31, 1n30, AMD MUREG-0737
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p0ST-TMI REQUI3EMENTS i
BROWNS FERRY NUCLEAR PLANT III.D.3.4 - CONTROL ROOM HABITABILITY (1) Control room mode of operation is discus' sed in section 10.12 of the BFN FSAR.
(2) Control room characteristics are discussed below:
3 (a) Volumeofhabitagilityforunits 1 and 2 is 4996 M and for-unit 3 is 2549 M (b) The control room emergency zones are shown schematically l
in FSAR figures 10.12-2 and 10.12-3.
(c) Control room ventilation system schematic is FSAR figure 10.12-2.
(d) BFN control room is maintained at a positive pressure as described in response to FSAR Question 10.2.
(c) High-efficiency particulate filter and charcoal absorber efficiencies are 99 percent, and 95 percent for elemental iodine, and 90 percent for organte and particulare, respectively.
(f) The closest distance between containment and air intor:es can be calculated frca FSAR figures in section 1.6 (g) Layout of control roon, air intakes, containment, and chemical storage facilities is shown in figures in FSAR section 1.6.
(h) Control room shielding and dose calculations are discussed in FSAR section 14.10.5.
' (i) Upon receipt of control room isolation signal, appropriate dampers are closed and all nonemergency fans are shut down.
(j) TVA' has updated the evaluation of the main control roon during a postulated hazardous chemical release, utilizir.g the guidelines presented in SRP 6.4 and Regulatory Guide 1.78.
See attached summary for results of study.
(k) The 3-unit control room complex is provided with 21 self-contnined breathing apparatus.
(1) The air supply stored in the control room complex is 21 man-hours.
(m)~ An unlimited potable water supply is provided from an offsite source. An emergency food ' supply is not maintained onsite;-however, food can be supplied as needed.
4 (n) Control roon personnel requirements are specified in section 4.0 of the BFN Radiological Energency Plan.
(o) The medical station maintains a 5000-dose supply of potassium iodine.
(3) As noted in response to iten (2)(j), the surrary of TVA's updated evaluation of main control roon habitability is provided in Attachrent A and discusses onsite storage of hazardous cheticals.
(4) As noted in response to iten (2)(j), the surrary of TVA's updated evaluation of nain control roon habitability is provided in Attachrent A and discusses offsite manufacturing storage and transportation facilities of hazardous chemicals.
(5) Technical specifications; based on our analysis, the present technical specifications are sufficient to ensure control roon habitability.
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ATTACl! MENT A BROWNS FERRY NUCLEAR PLANT Item III.D.3.4 - Control Room Habitability - Evaluation The habitability of the main control room was evaluated utilizing the approach outlined in Regulatory Guide 1.78.
Potential hazards resulting from chemicals stored on or near the site or chemicals that are transported to the site by barge, rail, or road were considered.
Two types of accidents were considered. The first is a maximum concentration accident.
This type of accident was evaluated using the computer program CHI 224, as outlined in Attachment B.
Major assumptions for this method were Pasquill Stability Class G and adverse wind ~ directions. The second type of accident wac a maximum concentration-duration accident.
This type of accident assumed a leak from the largest relief valve and was evaluated in accordance with positions C.5 and C.6 of Regulatory Guide 1.i8.
Results of the analysis indicated:
1.
Chemicals shipped by rail and road will not affect main control room habitability since all major roads and rail lines lie outside the 5-mile radius specified in Regulatory Guide 1.78.
2.
Inere are no industrial or military facilities within the 5-mile radius specified in Regislatory Guide 1.78.
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3.
Noac of the chemicals stored onsite in quartitics greater than 100 pounds af fect main control room habitability on tha lupture of the single largest container.
4.
Of the chtmicals barged past the site, only chlorine will affect main control room habitability. The snalysis showed that an accident where more than 5 tons of chlorine is vaporized will cause the concentration ig the control room to exceed the toxicity limit of 45 mg/m.
Although compliance with Regulatory Guides 1.78 and 1.95 is not a licensing requirement for Browns Ferry, in order to meet guidelines in NUREG-0737, TVA is evaluating the need for chlorine detectors to be installed in the main control room intakes.
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s ATTACIFENT B Item III.D.3.4 CllI224, A PROGRAM FOR CALCULATING Tile EFFECTS OF A IIAZARDOUS CilEMICAL RELEASE ON IIAIN CONTROL ROOM llABITABILITY Concentration levels of toxic gases within the control room area can be determined by use of the CIII224 program.
The analytical model utilized in the program is that for the " puff" release accident presented in NRC Regulatory Guide 1.78.
Major assumptions within the wind program include:
(1) " puff" release of the gas being considered at time = 0, (2) wind directed from the accident site toward the plantsite, (3) instantaneous homogenous mixing within the control room, and (4) a Gaussian atmospheric dispersion model. Some of the specialized features include:
(1) branching for Pasquill Stability type, (2) control room isolation considerations, and (3) control building configuration consideration.
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