ML19246A897
| ML19246A897 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 06/29/1979 |
| From: | Short T OMAHA PUBLIC POWER DISTRICT |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7907090198 | |
| Download: ML19246A897 (4) | |
Text
.
A. ww
.- 4 Omaha Public Power District 1623 HARNEY a
OMAMA. NEBRASKA ( '102 s TELEPHONE 536 4000 AREA CODE 402 June 29, 1979 Director of I!uclear Reactor.7egulation A7.
Mr. Robert n'. Eeid, Chief Operating Reactors Branch Iio. k U. S. :iuclear Regulato.7 Cc ission
~ 'ashington, D. C.
20555 n
Re ferenc e :
Docket :io. 50-265 Gentlenen:
In accordance with Section 3.2.1 of the Fort Calhoun Station fire protection Safety Evaluation Report (SER), issued by the Cornission on August 23, 1976, the Omaha Public Fover District herewith submits five (5) copies of a qualitative report addressing the effects on safety related equipment of rupture of the fire water piping to be installed at the Fort Calhoun Station. This report (attached) includes:
(1) a description of the assumptions to be used to quantitatively evalus.te the effects on safety related systems of fire water piping rupture and (2) design considerations to be employed to citigate the consequences of fire water piping rupture.
A quantitative analysis addressing specific fire water piping vill be submitted to the Commission in Ilovember,1979, when design of the piping referenced in Section 3.1.5 of the SER is completed. The quanti-tative analy0is depends upon the actual physical location of the piping systems in the Fort Calhm un Station auxiliary building. The Co ission is respectfully requested to provide titely rMev of the attached qualitative data in order that the preparation of the quantitative analysis may proceed according to schedule.
Sincerely,
! /
Nf @'[
7. E. Short Assistant General Manager
'"ES /KJM/EJH : j n
- Attach, cc:
LeBoeuf, Lamb, Leiby & MacRae
' 97 1333 :iew Harpshire Avenue, I;. W.
En j
Washington, D. C.
20036 7907000\\%
ATTACHMENT Qualitative Report Effects of Fire Water Pipe Rupture on Safety Related Equipment at the Fort Calhoun Unit I Nuclear Power Station I. The new auxiliary building fire hose system for Fort Calhoun Unit I will operate at ambient temperatum and at a pressure of 125 psig and is, therefore, classified 6c noderate energy piping in Branch Technical Position MEB 3-1.
Piping cracks shall be postulated in the Fort Calhoun Unit 1 auxiliary building fire hose moderate energy fluid system, which during nomal plant conditions, will be either in operation or maintained pressurized '(above atmospheric pressure) under condi-tions whem both of the following are met:
maximum operating temperature is 200 F or less, and maximum operating pressure is 275 psig or less Fluid flow from a crack shall be based on a circular opening of area equal to that of a rectangle one-half pipe diameter in length and one-half pipe wall thickness in width. The flow from the crack shall be assumed to result in an environment that wets all unprc-tected components within the compartment, with consequent flooding in the compartment and communicating compartments.
Flooding effects wili be detemined on the basis of a conservatively esti-
~
mated time period required to effect corrective action.
~
II. Through-wall leakage cracks will be postulated for the Fort Calhoun Unit I auxiliary building fire hose moderate energy piping system in accordance with the following criteria:
1.
Cracks will be postulated at locations that are isolated or physically mmote from essential systems and components.
2.
Cracks will not be postulated in pipes of nominal pipe size of I in. and less.
3.
Cracks wiii De postulatec to occur incivicually, at locations that result in the maximum effects from fluid spraying and flooding.. Only environmental effects that.
develop from these crack! shall be considered.
l'f n
II. (Continued)
Cracks shall be postulated in the fire lines and only environmental effects (flooding, sp,ay, etc.) shall be considered for protection of safety-related components.
The flow frcm a crack is assumed to result in an environment that wets all unprotected components within the compartment, with consequent flooding in the compartment anc comunicating compartment.
III. The following steps shall be taker, duriig piping design and instal-lation to protect =; gainst the effects of pipe cracks:
1.
Essential
- instruments and components shall be sealed or otherwise capable of operating in a wet environment.
2.
Adequate drains, flood barriers, or bulkheads shall be provided to prevent flooding of essential equipment.
3.
Essential
- instruments and comoonents shall be elevated to minimize tne potential for flood damage, as appropriate.
4.
The fire protection piping will be located renote from safety-related equipment to the greatest extent possible.
5.
Whena the piping must be located adjacent to safety-relatec equipment, the piping and its supports will be seismically designed.
6.
Adequate spray shields will be provided where necessary to prevent entrance of spray into existing safety-related electrical panels.
7.
Piping will be routed so as to take maximum advantage of existirg structure, conduits and cable trays to break-up and disperse spray.
' Equipment necessary to safely shut down the plant and maintain it in a safe shutdown condition.
p
?%
ReTerence3 1.
I;R: Standard Eeviev Plcn, Section 3. 6.1, March lo75, entitled " Plant Lesign for Prctection Against Postulated Piping Failures in Fluid Systems Outside Containment", containing 3 ranch Technics.1 Position 120S3 3-1, 2.
IiRC Standard Reviev Plan, Section 3.6.2, March 1975, entitled " Deter-
=ination cf Breat Locations and Dynamic Effects Associated With the Postulated Rupture of Piping", containing 3 ranch Technical Position ICS 3-1.
3 Letter from A. Cie=busso, Deputy Director for Reactor Projects, to I!USCO President, Decenber 1972, requiring consideration of piping syste breat outside the conte.inment.
30
- c, A
M h