ML20071C449
| ML20071C449 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 02/25/1983 |
| From: | Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO. |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| SBN-481, NUDOCS 8303020083 | |
| Download: ML20071C449 (3) | |
Text
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SEABROOK STATION
% ONke:
1671 Worcemer Rood WW, m om Pub 5c Service of New Hampshire (617) - 872 - 8100 February 25, 1983 SBN-481 T.F. B7.1.2 United States Nuclear Regulatory Commission Washington, D. C. 20555 Attention:
Mr. George W. Knighton, Chief Licensing Branch No. 3 Division of Licensing
References:
(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) PSNH Letter, dated April 8, 1982, "Recponse to 460 Series RAIs; (Effluent Treatment Systems Branch)," J. DeVincentis to F. J. Miraglia
Subject:
Open Item Response; (SRP 11.3, RAI 460.27, Meteorological and Effluent Treatment Systems Branch)
Dear Sir:
We have enclosed a revised response to NRC Request for Additional Information 460.27 regarding hydrogen control in the Radioactive Gaseous Waste System cubicles.
The original response to RAI 460.27 was submitted in Reference (b). The enclosed response will be incorporated in OL Application Amendment 49.
Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY J. DeVincentis Project Manager ALL/fsf cc: Atomic Safety and Licensing Board Service List 8303020083 830225 1
PDR ADOCK 05000443 NI A
PDR 1000 Elm St., P.O. Box 330. Monchester, NH 03105. Telephone (603) 669-4000. TWX 7102207595
ASLB SERVICE-LIST l
Philip Ahrens, Esquire i
Assistant Attorney General Department of the Attorney General Augusta, ME 04333 Representative Beverly Hollingworth Coastal Chamber of Commerce 209 Winnacunnet Road Hampton, NH 03842 William S. Jordan, III, Esquire Harmon & Weiss 1725 I Street, N.W.
Suite 506 Washing ton, - DC 20006 E. Tupper Kinder, Esquire Assistant Attorney General Office of the Attorney General 208 State House Annex Concord, NH 03301 Robert A. Backus, Esquire 116 Lowell Street P.O. Box 516 Manchester, NH 03105 Edward J. McDermott, Esquire Sanders and McDermott Professional Association 408 Lafayette Road Hampton, NH 03842 Jo Ann Shotwell, Esquire Assistant Attorney General Environmental Protection Bureau Department of the Attorney General One Ashburton Place, 19th Floor Boston, MA 02108
460.27 3ection-11.3.2.2 states that some cubicles'of~the RGWS will be continuously monitored for H2 and that in the event _ of high H2 concentration:
i a)
The affected components of the process stream will be isolated and/or.the affected component. purged with N 3 2
b)
The affected cubicle.will be ventilated to reduce the H2 concentration; and c)
Unnecessary personnel will be evacuated from the area.-
It" appears that the ventilation to reduce H2 concentration could result in the addition of air in the ventilation systems in the ambient carbon delay bed and the hydrogen surge tank area, thus resulting in a potentially explosive mixture. Another potential source of 02 could be the air conditioning units. ' Provide an analysis to show that the addition of air in these cubicles of the RGWS would not result in a deflagration or an explosive.
RESPONSE
Exhaust ventilation air associated with cubicles within the Waste Processing-Building, servicing the Radioactive Gas Waste System (RGWS) components, is greater than the air supplied. Potential leakage from the RGWS components will be vented along with normal building exhaust air to the atmosphere via Unit 1 plant vent.
In addition, the RGWS operates at a slight positive. pressure. These i
design features preclude the possibility of introducing ventilation air into the RGWS in the event of a leak. In addition, detection of abnormal levels of hydrogen within cubicles servicing the RGWS will call for the isolation of the affected components of the RGWS and/ot the affected component being purged with nitrogen. Normal building ventilation flow will be maintained in the event of abnormal levels of hydrogen within compartments servicing the RGWS. Abnormal levels of hydrogen within the hydrogen surge tank-cubicle will automatically activate an additional purge system of 20,000 SCFM. These normal or additional ventilation air flows will dilute and reduce any hydrogen co..centrations in the affected compartments. This dilution decreases the. possibility of hydrogen deflagration or an i
explosion.
l The RGWS itself has redundant oxygen detection at the inlet of the chillers. An alarm of the trace oxygen analyzers will call for an isolation of the RGWS and identification and repair of the source i
of oxygen introduction.
The above procedures and equipment design are all designed to l
preclude the possibility of deflagration or an explosion.
However, the RGWS has been designed to withstand an internal l
hydrogen explosion.
An analysis of the potential radiological consequences of l
accidental releases from the RGWS is presented in FSAR Chapter 15, Section 15.7.1.
Based on the above, the addition of air into cubicles housing the RGWS ' components will not result in an increase of the potential of l
hydrogen deflagration or an explosion.