ML19262C101
| ML19262C101 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 01/24/1980 |
| From: | Vandenburgh D YANKEE ATOMIC ELECTRIC CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| WYR-80-11, NUDOCS 8001280298 | |
| Download: ML19262C101 (5) | |
Text
9 Telephone 617 366 9011 wx 7'O - 3 90 ^ 7 3 9 YANKEE ATOMIC ELECTRIC COMPANY n.3.2.1 WYR 80-11
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W 20 Turnpike Road Westborough, Massachusetts 01581
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January 24, 1980 United States Nuclear Regulatory Commission Washington, D. C.
20555 Attention: Office of Nuclear Reactor Regulation
Reference:
(1) License No. DPR-3 (Docket No. 50-29)
(2) Letter, D. F. Ross, USNRC to Cordell Reed, Chairman, Westinghouse Owners' Group, dated December 27, 1979
Enclosure:
(a) Error Analysis of Subcooling Instrumentation for Yankee Rowe
Dear Sir:
Subject:
Documentation of Errors Associated with Subcooling Instrumentation at Yankee Rowe.
The staff requested, in Reference (2), documentation showing the errors, their source and the method of error analysis employed in establishing the subcooling criterion for ECCS termination. The errors and error analysis associated with the subcooling instrumentation currently being installed at Yankee Rowe are provided in Enclosure A to this letter. The 400F subcooling criteria for ECCS termination at Yankee Rowe is not derived from an error analysis of the subcooling instrumentation, it is based upon achieving a stab 1v. primary condition (without main coolant pumps operating) at 1800 psig rida the secondary system pressure at 935 PSIG (lowest SG safety valve set pressure). Thus, taking into account the error associated with the subcooling temperature instrumentation (+ 130F) delineated in Enclosure A, a primary subcooling condition of greater than 200F is guaranteed.
Currently, the non-LOCA transients and Emergency Operating Instructions are being reviewed by Westinghouse on behalf of the Westinghouse Owners' Group for the purposes of incorporatins a subcooling criterion in the ECCS These activ *ias will be completed and transmitted to termination criteria.
i the NRC by the owners' Group Chairman within the 21 day requirement.
As mentioned above, subcooling instrumentation is currently being installed at Yankee Rowe and will be operable before power operation is resumed.
Since this instrumentation has been shown in Enclosure A to have 1816 164 ooonsoz-w
United States Nuclear Regulatory Commission January 24, 1980 Attention: Office of Nuclear Reactor Regulation Page Two a + 130F subcooling uncertainty, 20 F of actual subcooling is ensured based upon Yankee Rowe's subcooling criterion. Thus, the January, 1981 requirement regarding instrumentation ensuring 200F subcooling requested in Reference 2 will have been met before power operation is resumed.
Finally, the redundancy of emergency power supplies to critical instrumentation is being evaluated under Yankee Rowe's response to IE Bullecin 79-27.
We trust that the above information is satisfactory.
If any questions should arise concerning this matter, please contact us.
Respectfully submitted, YANKEE ATOMIC ELECTRIC COMPANY
@E.N" D. E. Vandenburgh Sr. Vice President WJS/scw Enclosure
Enclosure (Al 1.0 STRUCTURE / SYSTEM /COMPON ENT This analysis applies to the Primary Coolant Saturation Monitor Installation at Yankee Rowe.
2.0 PROBLEM DESCRIPTION This analysis determines an overall error to be factored into the alarm set point evaluations for Combustion Engineerings Subcooled Margin Monitor. The analysis will use the root sum square method. Accuracy data from available vendor data sheets will be used.
3.0 DETAILS OF A?U. LYSIS A.
Errors in indicated pressure.
1.
Equipment Rosemount Pressure Transmitter Model 1152, 0-3000 psig Rosemount Pressure Transmitter Model 1153, 0-3000 psig 2.
Normal Accuracy Calculation a.
Normal Accuracy
+.25% of span = +.25% (3000)
= + 7.5 psig b.
Calibration Equipment Accuracy
+.25% of span = +.25% (3000)
= + 7.5 psig c.
Pressure Transmitter Calibration Accuracy
.25% of span = +.25% (3000)
+
= + 7.5 psig d.
Ambient Temperature Ef fects
+ 1.0%/1000F (Model 1152)
[1.25%/100 F (Model 1153)
This temperature effect accounts for both span and zero adjustment. Assuming that the transmitter is calibrated at X F and the transmitter location will normally be O
X F + 20 F the temperature effect will actually be:
O
+.2%
(Model 1152)
+.25% (3000)
I.25% (Model 1153) = 7 7.5 psig e.
Stability / Drift
}O}b lb6
.25% of span = +.25% (3000)
+
= + 7.5 psig
s f.
Rochester Instrument System I/I isolator Model SC1302 Accuracy +.2% of sp.,n =.2% (3000)
= 6.0 psig Stability /Dri f t +.5%/500F (Control room environment at 700 + 100, therefore stability / drift is +.1%) = +.1% (3000)
= 3 psig Using the root sum square method E r s s = T/5( 7. 5) 2 (3)2
= 18.06 psig (6)2
+
+
Erss =3/5(.25)2
(.2)2
(,1)2 =.6%
+
3.
Maximum Post-Accident Environment Error
+ 2.0% (Model 1152)
+ 5% (3000)
+ 5.0% (Model 1153) =
150 psig 4.
Total Maximum Pressure Instrument Error (ETMAX)
Total Normal Accuracy + Maximum Post-Accident Error = ETMAX 18.06 psig + 150 psig 168.1 psig
=
or
.6% + 5.0%
5.6%
=
B.
Errors in Indicated Temperature 1.
Eouipment Core exit T/C type K RIS T/C Transmitter SCl306 2.
Normal Accuracy Calculation a.
Normal Accuracy 0-5300F+2F
.375% (700)
= +
~
530-7000F +.375 %
2.6 F b.
Calibrated Accuracy
+.5GF c.
RIS T/C Transmitter 1816 167
.2% (700)
+.2% accuracy
=
Stability / Draft
= 1.40
+ 1%/50"F (assuming control room environment changes + 100, stability and draft would be =.2% (700)
+.2%)
= 1.4o Using Root Sun Square Method:
Erss =3/(2.6)2 + (,5)2 + (2)(1.4)2 + = 3.31 F 3.
Maximum Post-Accident Environment Error
+.01% (700)
Error equivalent to 2 junction
=
.10F boxes
=
4.
Total Error for Temperature Indication Add results of 2 and 3 yields + 3.40F C.
Determine Largest Possible T-margin Normal operating temperature is approximately 5500F and assuming highest pressure of system to be 2500 psig (when safety valves open) therefore the following correlations are determined:
A system pressure of 2500 psig (2514.7 psia) corresponds to 669.00F saturation temperature A system temperature of 5500F corresponds to 1045.54 psia saturation pressure, resulting in:
Maximum temperature margin of 119.00F Maximum Pressure Margin of 1469.2 psia = 1483.9 psig D.
Calculation of Subcooling Margin Worst case for calculating margins is when Psys has (+) error and Tsys has (-) error.
Psys 2500 psig could be off +5.6% or 2640 psig = 2657.7 psia Tsys 5500 could be off -3.40F = 546.60F Psys 2657.7 psia Tsat 677.150F Tsys 546.60F Psat 1016.84 psia Resulting T margin + P margins are:
T margin = Tsat - Tsys = 677.15 - 546.60F = 130.550F 1816.168 s
P margin = Psys - Psat = 2657.7 - 1016.84 = 1640.86 psia Adding the CE monitor error of.5% to each margin calculation:
T margin = 130.55(1.005) = 131.20F P margin = 1640.86(1.005) = 1649.06 psia Compare T & P margins with errors to actual T & P margins:
T margin w/ error - T margin actual = 131.2 - 119.0 = 12.20F P margin w/crror - P margin actual = 1649.9 - 1469.2 = 179.8 =
165.1 psig Calculating margins for other possible Psys and Tsys error combinations as above yields the following:
Psys Tsys Tmargin Pmargin
(+) error
(-) error
+12.2oF
+165.1 psig
(+) error
(+) error
+5.4oF
+1397U psTg
(-) error
- F) error
- 4.SoF--
-89 6 IFig ~
i
(-) error F) error
-7190F
~~
7 74~.4~p~sig NOTE: A (+) margin denotes that the indicated margin real margin A (-) margin denotes that the indicated margin real margin 4.0 Conclusion This analysis has shown that the worst case errors for the primary coolant saturation calculation would produce an error of +12.20F for T margin and 165.1 psig for P margin. Therefore, a minimum of 130F T margin (170 psig P margin) must be maintained in order to ensure adequate core cooling conditions.
.