ML20126B177
| ML20126B177 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 10/09/1973 |
| From: | James Shea US ATOMIC ENERGY COMMISSION (AEC) |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 9212210435 | |
| Download: ML20126B177 (3) | |
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UNITED STATES 7
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001 U 1973 Files (Docket No. 50-263)
THRU Dennis L. Ziemann Chi ORB #2, L IVUR ADDITIONAL TARGET ROCK RELIEF / SAFETY VALVES FOR THE HONTICELLO CORE COOLANT SYSTEM (NORTHERN STATES POWER COMPANY)
Representatives of Northern States Power Company (NSP) met with AEC Licensing representatives in Bethesda, Maryland, on September 27, 1973, to discuss NSP plans to replace the four (4) existing spring-
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loaded safety valves on the Monticello steam lines with four (4) additional Target Rock Relief /$afety Valves identical to the four already in service.
(Total of.eight (8) Target Rock Relief Valves.)
The specific purpose of the meeting was to reach agreement on applicable code requiren.ents for the proposed modification, i.e.,
removing the four safety valves and installing four additional safety / relief valves.
NSP stated that the modifications will be accomplished in so far as possible in accordance with the requirements of Section XI of the ASME Boiler and Pressure Vessel Code, through the Summer 1973 Addenda, and consistent with these requirements the une of the design code editions applicable to the construction of the components. The staff indicated that this general approach was acceptable.
NSP displayed a piping isometric drawing that will be used in analyzing stresses in the steam lines and the 10-inch lines-from the relief / safety valves to the torus. New, as well as old, steam relief lines to the torus will-be analyzed. There are no plans to lift relief valves and obtain confirmatory data to demonstrate the calculational adequacy.
Discussion brought out that NSP is considering prompt relief valve l
actuation from a turbine isolation valve signal following turbine trip transient as a further means of reducing the resultant transient peak pressure. Such a change w< 21d provide an even larger margin between peak pressure and the system overpressure design value.of 1375 psig.
l The advantages and disadvantages of retaining the existing safety valves af ter adding the four new safety / relief valvas were.to be described in the proposal currently being prepared by NSP for AEC approval.
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NSP estimated that a proposal to add additional safety / relief valves and a safety analysis of the proposed modification will be submitted to the AEC by November 20, 1973, so that the proposed modifications j
can be completed during the Monticello fuel reload currently scheduled for late February 1974.
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Enclosures List of Attendees cc w/ enclosures L. O. Mayer, NSP Docket Files (50-263)
AEC PDR Local PDR L Reading File RP Reading File RP/TR Assistant Directors RP/TR B1anch Chiefs T. J. Carter, L 0R J. M. llendrie TR J. J. Shea, L 0RB #2 R. Bevan, EP #4 OGC E0 (3)
Reg Attendees ACR0 (16)
R. M. Diggs, L 0RB #2 P. Johnson, RO #111
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LIST OF ATTENDEES _
HEETING WIT 11 NORTilERN STATES POWER COMPANY
_ RELIEF / SAFETY VALVES, SEPTDiBER 27, 1973 i
Northern Staten Power Company Bechtel Power Corporation 4
J. F. Swedberg C 11ogg M. Bjeldanes C.11. Harmsen AEC - Licensing R. Jensen J. J. Shea 1
Ceneral Electric Company R. W. Reid J. P. Knight L. J. Chockie S. Ilou G.11. Scott 1
T. N. Czaplicki l
Nuclear Services Co poration 1
G. Randall 4
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