ML20054H928
| ML20054H928 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 06/15/1982 |
| From: | Kay J YANKEE ATOMIC ELECTRIC CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-15-16, TASK-RR FYR-82-63, NUDOCS 8206250211 | |
| Download: ML20054H928 (3) | |
Text
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YANKEE ATOMIC ELECTRIC COOPANY
" * " * ' -a'oo ST-
,Ya}ux.,N 1671 Worcester Road, Framingham, Massachusetts 01701 es June 15, 1982 FYR 82-63 2.C.2.1 United States Nuclear Regulatory Commission Washington, D. C.
20555 Attention:
Mr. Dennis M. Crutchfield, Chief Operating Feactors Branch #5 Division of Licensing
References:
(a) License No. DPR-3 (Docket No. 50-29)
(b) USNRC Letter to YAEC, dated March 25, 1982
Subject:
Additional Information for SEP Topic XV-16
Dear Sir:
The attached information has been prepared in response to Feference (b).
This information provides clarification for the assumptions used to assess SEP Topic XV-16, Failure of Small Lines Carrying Primary Coolant Outside Containment.
If you have any questions, please contact us.
Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY J. A. Kay Senior Engineer - Licensing JAK/ tan 8206250211 820615 PDR ADOCK 05000029 P
YANKEE ATOMIC SEP TOPIC XV-16 1.
NRC Concern Yankee's evaluation states, "... operators would be signaled as soon as the leakage exceeded the makeup capability of a single charging pump."
State what the signal would be, how the operators would identify the line, and how the line would be isolated. Specify the location of the isolation valves.
YAEC Response When the makeup capability of a single charging pump is exceeded, an alarm signals the start of the remaining two charging pumps (auto start in standby). These pumps start on decreasing pressurizer level.
The charging and letdown lines are enclosed and shielded within the radioactive pipe chase leading to the Primary Aux 11ary Building. Line identification would be either by personnel investigation or by area radiation monitors. These lines would be isolated by securing the charging pump, check valves in the charging lines (CH-V-611, 611A), or by the following letdown line valves operated from the Control Room:
Valve I.D.
Location CH-MOV-525 Vapor container Vari-orifice Vapor container CH-MOV-527 Vapor container LCV-222 PAB valve room 2.
NRC Concern Discuss the basis for the flow rate assumed, as compared to the flow rate that would be calculated by the method recommended in Standard Feview Plan 15.6.2:
" amount of primary coolant released is conservatively estimated by assuming critical flow at the small line break location with the reactor coolant fluid enthalpy corresponding to normal reactor operating conditions."
YAEC Response The flow rate used in our analysis conservatively calculated assuming maximum 3 pump charging flow of 99 gpm.
This flow is assumed to occur for 30 minutes before termination (i.e., resultant spill = 2970 gal).
Normally, only one charging pump is in operation (i.e., during normal operation the vari-orifice is set at 20 gpm), with the remaining two pumps in auto-standby. As soon as the capacity exceeds one pump, the operator is alerted by alarm (auto-start of the 2 pumps) to investigate the situation.
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3.
NFC Concern i
Give the inner diameter and length (from reactor to outside of containment) of the instrument line for which the break was evaluated, and the basis for the 10 gpm leak assumed.
YAEC Response The 3/8 " instrument tubing has an inner diameter of 0.305."
The length of tubing from containment to the instrument is approximately 60 feet.
The flow rate from this line has been recalculated to be 21 gpm based on
.a 2200 psi differential pressure with single phase water flow.
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