ML19340F014
| ML19340F014 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/13/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-3.D.3.4, TASK-TM NUDOCS 8101160494 | |
| Download: ML19340F014 (3) | |
Text
--
TENNESSEE VALLEY AUTHORITY
~
CH ATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II
)
January 13, 1981
,j c'
'u ElT,6 g
[h n
== n 1
in
~7 Director of Nuclear Reactor Regulation p
.o Attention:
W. A. Schwencer, Chief N
Licensing Branch No. 2 i
Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Schwencer:
In the Matter of the Application of.
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 NUREG-0737, Clarification of TMI Action Plan Requirements, item III.D.3.4, requires TVA to submit documentation on control room habitability. The following is the required documentation.
The plant design for Sequoyah ensures that the operators in the control room are adequately protected against the effects of accidental release of toxic and radioactive gases and that Sequoyah can be safely operated or shut down under design basis aooident conditions. Documentation of the j
design and analyses has been submitted as part of Sequoyah Final Safety Analysis Report sections 2.2.1, 2.2.2, 2.2 3, 6.4, and 9.4.1.
Addition-rlly, the chlorine detection system and control room ventilation system are covered by Sequoyah unit 1 technical specifications 3/4 3 3.6 and 3/4 7 7, respectively.
TVA has rwoontly completed updating the habitability evaluation of the main control room utilizing the approach outlined in Regulatory Guide 1.78.
Additional details on this update are enclosed. TVA has concluded that the i main control room habitability is not jeopardized by accidental release of the chemicals considered.
If you have any questions, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, r
Nuclear Regulation and Safety Sworn / aday of Wm -
d subscribed before me i
t 1981 n1 Af
~ Notary Public
- d-My Commission Expires An Equal Opportunity Employer 1 8A 1 b
ENCLOSURE SEQUOYAH NUCLEAR PLANT Item III.D.3 4 - control Room Habitability 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 by 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 the attachment. Major assumptions for this method were Pasquill Stability Class G and adverse wind directions. The second type of accident was 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 78.
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 178.
2.
There are no industrial or military facilities within the 5-mile radius specified in Regulatory Guide 1.78.
3 Hazardous chemicals barged past the site are transported less i
frequently than the minimum frequency of 50 barges per year required for consideration as specified in Regulatory Guide 1 78.
4.
None of the chemicals stored onsite in quantities greater than 100 pounds affect main control room habitability on the rupture of the single largest container.
TVA has concluded that the main control room habitability is not jeopardized by accidental release of the chemicals considered.
I l
i i
i
l ATTACHMENT Item III.D.3.4 CHI 224, A PROGRAM FOR CALCULATING THE EFFECTS OF A HAZARDOUS CHEMICAL RELEASE ON MAIN CONTROL ROOM HABITABILITY Concentration levels of toxic gases within the control room area can be determined by use of the CHI 224 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.
I