ML20093J091
| ML20093J091 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 02/07/1984 |
| From: | STONE & WEBSTER ENGINEERING CORP. |
| To: | |
| Shared Package | |
| ML19269A632 | List: |
| References | |
| CSD-2-84-13, NUDOCS 8410160491 | |
| Download: ML20093J091 (7) | |
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3 CSD-2-34-13 February 7, 1984 STONE % WEBSTER
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.s TESTING OF LAN 7075-3 pH RECEIVER AND ELECTRODE PTS. AMPLIFIER AND ERIDIAN pH ELECTRODE FOR PASS APPLICATIONS l
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I CSD-2-84-13 February 7, 1984 StM MRY AND CONCLUSION This report gives testing results of an L&N 7075-3 pH Receiver and Electrode Preamplifier and Meredian pH Electrode for use in post-accident sample systems (PASS).
The testing protocol involved setting up the system with two buffers followed by standardizing the system with 7.00 buffer.
Buffers covering 1.00 to 13.00 were used to tett the system for accuracy.
PWR simulated reactor coolant and sump water with matrix fission products were used to verify system performance.
The NRC gives a pH range for PASS applications of 1.0-13.0 (1).
The accuracy requirement is ! 0.3 pH unit between pH 5.0 and 9.0 and f 0.5 pH unit for other ranges (2).
This testing shows that the L&N system meets this requirement.
(1) Reg. Guide 1.97, Revision 2 (2) NUREG 0737 (Section II.B.3, Evaluation Criteria Guidelines)
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CSD-2-84-13 February 7,1984 MATERIALS USED IN TESTING 1
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The L&N Meredian general purpose combination pH electrode (No. 117489) was connected ta (the ;L&N 7075-3 pH Receiver and Electrode Preamplifier., Because a.tsmperature compensator was not used, a M
720.5 ohm resistor was connected between terminals "TM" and "TA" on the preamplifier unit.
The electrode was mounted in an L8N 7775 Meredian Insertion-T);pe Electrode Mounting.
s The following conc,ercial buffers were used in the test:
M Ingredients Fisher No.
Lot No.
1.00 KC1 + hcl So-B-140' 735878-18 HOCOC H C00K+ hcl So-B-97 '
735442-24 3.00 54 5.00 HOCOC H C00K+NaOH So-B-102 735444-24 64 7.00 KH P0 +NaOH So-B-109 733683-24 2 4 9.00 H 80 + kcl +NaOH So-B-114 734920-24 3 3 11.00 NaOH+Glycoco11+ Nacl So-B-142 735447-24 r
- A pH 13 buffer was not commercially available, but was prepared in the NUS laboratories.
The pH 13 buffer was 660 mL 0.2M sodium hydroxide, 250 mL 0.2M potassium chloride diluted to 1000 mL. -
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CSD-2-84-13 February 7, 1984 TESTING IETHOD The pH electrode was soaked in water for nearly two days before testing.
The L&N system was buffered with the pH 3.00 buffer using the " Standardize" control.
When the electrode was removed from a solution; the " Standardize" control was pulled out to place the system in " Standby" to ensure that the electrode would not become polarized. The L&N system was then buffered with the pH 11.00' buffer, but the " Span or Slope Adjust" (R41) was used for this adjustment.-
The pH 7.00 buffer was then used, and the instrument was set with the " Standardize" control if required.
All readings were taken under static conditions.
Table 1 gives testing results for the buffers.
After the first test on January 31, the meter read low for the pH 11.00 and 13.00 buffers.
This indicates a possible need to reset the isopotential point, which cannot be easily adjusted with the L&N meter.
All subsequent measurements were made after using the pH 5.00 and 9.00 or 3.00 and 11.00 buffers to initially set up the system, followed by a final adjustment with the pH 7.00 buffer.
Since the measurements were made at 25 t 100, no temperature corrections to the measured values.were necessary.
As a control, three laboratory pH meters were used:
Orion 701, Orion 901, and Fisher Accumet 750.
These meters were set up using the pH 5.00 and 11.00 buffers.
The test continued over a four day period using the buffers.
PWR post-accident matrix solutions were also tested.
A reactor coolant matrix with 2000 ppm boron as boric acid and simulated fission products and a sump water with 2000 ppm boron as boric acid, sodium hydroxide, and simulated fission products were tested, These results are also given in Table 1.
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CSD-2-84-13 February 7, 1984
.. p EVALUATION OF TESTING RESULTS Table 2 gives a statistical evaluation of the testing results. The required accuracy between pH 5 to 9 is t 0.3 pH unit.
For the range 1 to 5 and 9 to 13 the required accuracy is t 0.5 pH unit.
Two means were used to evaluate the testing. results.
The first method tests for possible bias by a linear regression. The equation M=a+bS 1
shows possible bias, where "M"
is the measured buffer pH, "S" is the standard buffer value, "a"
is the bias, and "b" is the slope.
A perfect system would have values of 0 and 1.00 for "a" and "b",
respectively.
The L&N meter shows a slight positive bias of +0.09, which is reasonable considering that the readout is no better than
! 0.1 pH unit.
However, the Orion 701 and Accumet 750 meters showed biases outside the readout, which is t 0.01 pH unit for these digital instruments.
The absolute values of the differences between the measured values and the actual values were evaluated for pH ranges:
1.00 - 13.00, 5.00 - 9.00, and 1.00 - 5.00, and 9.00 - 13.00 to test for accuracy requirements given by the NRC.
The L&N meter shows an overall deviation as follows:
pH Range Expected Uncertainty, It + 2 o-1.00 - 13.00 0.40 5.00 - 9.00 0.29 1.00
. 5.00 and 9.00 - 13.00 0.47 These results confirm the suitability of the L&N system for PASS applications.
(Normally, analytical uncertainty is given at the one sigma level.
Since this was not defined in NUREG 0737, the two sigma values are used here).
Table 1 matrix testing results also confirm the suitability of the L&N - system.
For example, the PWR reactor coolant matrix varies between 5.4 and 5.5.
The overall uncertainty of f 0.29 fo' this pH range covers the two values of 5.64 and 5.48 measured with the Orion 901 system.
The sump matrix also verifies suitability of' the L&N system: an uncertainty of 0.47 applied to the measured values of 9.3 - 9.4 covers the 9.74 - 9.32 values measured with the Orion 901, although the 9.74 value is suspect.
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CSD-2-84 -
- TABLE, ruar A ; M 4 4
pH TESTING RESULTS FOR BUFFERS AND PWR MRTRIX i
PWR PWR acs-sump Date Time pH Meter Temp 2C pH1 pH3 pil5 pH7 pH9 pH11 pH13 Matrix Matrix Buffer (1) 1-31-84 1030 L8N 25.7 1.1 2.9 5.0 7.0 8.9 10.6 12.4 3-11 1715 Orion 701 26.0 0.90 2.84 4.91 7.01 9.00 10.94 12.87 3-11 2-1-84 1500 LAN 25.6 1.1 3.0 5.2 7.4 9.3 11.0 13.0 3-11 1650 Orion 701 26.0 0.79 2.74 4.84 6.95 8.98 11.0 12.92 3-11 2-2-84 0855 LAN 25.0 0.90 2.7 5.0 7.1 9.0 11.0 12.8 5.4 9.3 5-9 i
{
1100 L8N 25.0 1.1 2.8 5.0 7.1 9.0 10.8 12.9 5.5 9.4 5-9 l
1315 L8N 25.2 1.0 3.0 5.0 7.1 8.9 11.0 12.6 5.5 9.2 3-11 1
1630 Orion 901 26.0 1.00 3.00 5.20 7.39 9.'45 10.98 13.57 5.64 9.74 3-11 1655 Orion 901 26.0 1.10 2.96 5.04 7.10 9.03 11.03 12.95 5.48 9.32 5-9 2-3-84 1030 LAN 25.0 1.1 2.9 5.0 7.1 9.0 11.0 12.7 5.5 9.3 3-11
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1315 L8N 25.4 1.1 2.9 5.0_
7.0 9.0 11.0 12.5 1645 Accumet f
750 26.0 1.25 3.07 5.20 7.27 9.24 11.02 13.10 5-9 i
1700 Accumet i
750 25.0 1.11 2.95 5.06 7.12 9.11 10.81 12.99 5-9 i
NOTE:
(1) This was the buffer pair used to set up the instrument prior to a series of measurinents. The pH 7.00 l
buffer was used for a final meter adjustment of the LAN system.
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CSD-2-84-13 February 7, 1984 l
TABLE 2 STATISTICAL EVALUATION OF pH METER TESTING l S-M l pH 1-13 pH 1-13 pH 5-9 pH<5>9 Neter a
b x
6' i
a-i c'
L&N 088,
0.982 0.114 0.147 0.071 0.110 0.146 0.164 0.172 1.011 0.095 0.081 0.055 0.061 0.125 0.084 Orion 701 Orion 901 0.029 1.014 0.144 0.187 0.202 0.181 0.101 0.192 Accumet 750 0.162 0.990 0.129 0.087 0.167 0.082 0.100 0.083 S=
Standard buffer pH H=
Measured buffer pH Xa Average difference, lS-Ml n
d' = Standard deviation M=
a+bS i
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