ML20097A773
| ML20097A773 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 08/08/1984 |
| From: | Policastro A ARGONNE NATIONAL LABORATORY |
| To: | Lehr J Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8409130373 | |
| Download: ML20097A773 (2) | |
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.sonw ARGONNE NATIONAL LABORATORY
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August 8, 1984 go.3?
I Mr. John Lehr Environmental and Hydrologic L
Engineering Branch l
Division of Engineering U.S. Nuclear Regulatory Commission Washington, DC 20555 t,
Dear John:
[
This letter provides our cctments on the proposed noise monitoring plan prepared by PECO for the Limerick Plant.
In general, the plan is satisfactory and was aimed at meeting the intent of the ASLB recommendations and our recommendations in the environmental impact statement.
Our discussion below focuses on t,hree issues which require modification or clarification in the l
proposed Noise Monitoring Plan.
(1) There is confusion concerning the definition of audibility.
The plan represents the ASLB ruling correctly as requiring citigative measures if the transformers core tones are audible at the site boundary.
- However, audibility is defined as any positive dB level above masking level for any of the four transformer tone frequencies, 120, 240, 360 and 480 Hz.
PECO states (r. 44, paragraph 1) that mitigative measures will be undertaken if any of those values are greater than 5 dB.
This 5 dB quantity undoubtedly comes from the Ver-Anderson report of Bolt Beranek and Newman, Inc. on transformer tones, but that 5 dB level (above masking) is the threshhold for individual complaints not audibility.
We, therefore, suggest a change in the wording that indicates that mitigative measures will be undertaken if any tonal noise component at the site boundary is simply greater than the masking level for that tone.
(2) A definition of masking level is given in paragraph 2,
- p. 4:
"The masking level is defined as 16 dB above ambient spectrum level."
This 16 dB is und (1961)gubtedly an average over all four tgnal frequencies obtained from Medwin More recent literature (Fidell,1982) updates those figures as follows:
"Medwin, Herman.
" Power Transformer Noise - Prevention and Cure."
General Electric Company Report GET-2968.
Power Transformer Department.
Pittsfield, Massachusetts.
August 1961.
bFidell, Sanford.
" Graphic Method for Predicting Audibility of Noise Sources."
U.S. Air Force Wright Aeronautical Labs Report AFWAL-TR-82-3086.
Wright-Patterson Air Force Base, Ohio.
1982.
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2 August 8, 1984 120'Hz 240 Hz 360 Hz 480 Hz Medsin (1961) 16.5 dB.
16.0 dB 16.0 dB 16.0 dB Fidell (1982) 17.5 dB 17.4 dB 17.8 dB 18.2 dB 1 Note that the ambient' spectrum tlevel is frequency dependent; furthermore, the.
new-1 reference by Fidell provides larger values than those of Medwin.
The
- Fidell figures 'are more accurate and should be used (on a frequency basis)
- ins tead.- - This cha'nge also happens.to favor the Applicant by increasing the masking level computed by about (1.0 + 1.4 + 1.8 +2.2)/4 = 1.6 dB.
(3).We agree-that the one time only nature of the Point Pleasant and Bradshaw ' reservoir ~ noise studies is sufficient' to determine if noise problems will exist.
-The-source-receptor distances are very short at both sites
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.i(r'eceptors -are at the plant-boundary), thereby eliminating any significant effects of. ground l cover or vegetat' ion.
At.the Limerick Plant site itself,.the prese'nce' or not 'of intervening trees may lead to differences worth measuring.
W. etpropose'that the Limerick site' study be done wice, once in winter and once
-in summer.
5 We.have ' enclosed with this letter text modifications to the PECO noise plan fori your consideration.
Please contact me at -(312) 972-5820 or (FTS) 972-5280 if you have any questions or' wish further clarification.
Sincerely,
) b.
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r-2 6%M M -
Dr. Anthony J. Policastro-Environmental Research Division-
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