ML20080P554
| ML20080P554 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 05/28/1982 |
| From: | Evans L, Painter R, Tuckman M DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML20080P419 | List:
|
| References | |
| CP-O-B-8100-08, CP-O-B-8100-8, NUDOCS 8402220581 | |
| Download: ML20080P554 (11) | |
Text
Form 34731 (10-81)
(Formerly SPD 10021)
DUKE POWER COMPANY (1)
ID No: CP/0/B/8100/03 PROCEDURE PREPARATION Change (s)_ O to PROCESS RECORD
/ Incorporated (2) STATION:
Catawba (3) PROCEDURE TITLE: Chemistry Procedure for the Determination of Silica (Manual Method)
(4) PREPARED BY: k.Id DATE:
,f.M42 (5) REVIEWED BY:
) [J M DATE:
J'4/~I3 Cross-Disciplinary Review By:
h-M ____
(6) TEMPORARY APPROVAL (IF NECESSARY):
By:
(SRO) Date:
By:
Date:
(7) APPROVED BY: N. $-
Date: 5 f 2.5 b (8) MISCELLANEOUS:
seviewed/ Approved By:
Date:
l Reviewed / Approved By:
Date:
l l
MASTER FILE l
8402220581 840215 l
PDR ADOCK 05000413 E
FORM SPD-1001-2 DUKE POWER COMPANY NUCLEAR SAFETY EVALUATION CHECK LIST Catawba X
X (1) STATION:
UNIT: 1 2
3 OTHER:
(2) CHECK LIST APPLICABLE TO: CP/0/B/8100/08 (3) SAFETY EVALUATION - PART A The item to which this evaluation is applicable represents:
Yes No / A change to the station or procedures as described in the FSAF or a test or experiment not described in the FSAR?
If the answer to the above is "Yes", attach a detailed description of the item being evaluated and an identification of the affected section(s) of the FSAR.
(4) SAFETY EVALUATION - PART B Yes No
/ Will this item require a change to the station Technical Specifications?
If the answer to the above is "Yes," identify the specification (s) affected and/or attach the applicable pages(s) with the change (s) indicated.
(5) SAFETY EVALUATION - PART C As a result of the item to which this evaluation is applicable:
Yes No
/ Will the probability of an accident previously evaluated in the FSAR be increased?
/ Will the consequences of an accident previously evaluated Yes No in the FSAR be increased?
l Yes No
/
May the possibility of an accident which is different f than any already evaluated in the FSAR be created?
Yes No Will the probability of a malfunction of equipment important to safety previously evaluated in the FSAR b
f e increased?
Yes No Will the consequences of a malfunction of equipment important to safety previously evaluated in the FSAR be increased?
Yes ho May the possibility of malfunction of equipment important to safety different than any already evaluated
/ in the FSAR be created?
Yes No Will the margin of safety as defined in the bases to any Technical Specification be reduced?
If the answer to any of the preceding is "Yes", an unreviewed safety question is involved. Justify the conclusion that an unreviewed safety question is or is not involved. Attach additional pages as necessary.
(6) PREPARED BY: /
DATE:
f-10 A (7) REVIEWED BY:
W DATE:
S"2782-(8) Page 1 of
/
-Fom 18855 (3-80)
~
DUKE POWER COMPANY ALARA EVALUATION CHECKLIST (1) Station Catawba I
X Unit:
1 2
3 Other:
(2) Checklist Applicable to:
CP/0/B/8100/08 (3) ALARA Evalue. tion Check those items below which were considered applicable during the preparation and review of this document.
Flushing and draining were used to minimize source - strength and con-tamination levels prior to performing an operation.
Permanent and/or movable shielding was specified for reduction of levels.
Use of permanent or temporary local exhaust ventilation systems was use..! for control of airborne contamination.
Operation was designed to be completed with the least practicable time spent in the radiation field.
Appropriate tools and equipment were specified for the operation to be performed.
The operation was designed considering the minimum number of people necessary for safe job completion.
Remote handling equipment and cther special tools were specified to reduce external dose.
Contamination - control techniques were specified.
The operation was designed to be conducted in areas of as low an exposure as practicable, Additional ALARA considerations were:
/
ALARA Principles were not considered since the procedure did not involve work in a radiation area.
(5) Prepared by: _
Date.f~ M-f '*'-
(6) Reviewed by:
//d 2< )6w Date J~" 2 7 ' M
CP/0/B/8100/08 DUI2 POWER COMPANY CATAWBA NUCIIAR STATION CHEMISTRY PROCEDURE FOR THE DETERMINATION OF SILICA (MANUAL METHOD) 1.0 DISCUSSION 1.1 Scope This procedure describes the manual colorimetric method for the determination of soluble silica in water.
It does not apply to particulate, organically bound, or molybdate unreactive silica.
1.2 Principle At a pH of approximately 1.2, ammonium molybdate reacts with silica and phosphate to produce heteropoly acids:
(NH )6 0 0 4H O + H PO4 + H (P(M 2 7)6) - SE 0 0
4 7 24 2
3 7
2 (NH )6 " 7 24 4H O + R SiO 0
4 + H (Si(H 2 7)6) 28H O 0
4 2
4 8
2 The formation of both the molybdic phosphoric and molybdic-silicic acids contribute to the yellow color of the solution.
To distinguish between these acids, oxalic acid is employed to destroy the molybdic phosphoric acid. Although the oxalic acid does not affect the molybdic-silicic acid which has already formed, it does prevent the fon -tion of any additional molybdic-silicic acid.
Aminonaphtholsulfonic acid reduces the molybdic-silicic acid to its corresponding heteropoly blue:
2 10 6(OH)S0 H + H (Si(M NH C H
2 7)6) 28H O + H4 (SiM0 0
12 40) 0 3
g 2
i
'The blue color is more intense than the yellow, therefore producing greater sensitivity.
The concentration of molybdic-silicic acid is directly proportional to the initial silica concentration, and the production of heteropoly blue is directly proportional to the molybdic-silicic acid.
The relationship between absorbance and concentration is linear and conforms to Beer's law.
Due to the difficulty of producing truly " silica free" water and the presence of silica in the reagents used in this determination, three blanks are prepared along with the standards.
Compensation for color in the reagents is achieved by zeroing the spectrophotometer with a blank which has the exalic acid added before the ammonium molybdate.
Reagent and water contributions is resolved by analyzing two water blanks with single and double reagent additions.
Compensation in water volume must be made for the increased reagent volume in the second blank.
The absorbance difference between the two addition schemes yields the absorbance and hence silica contribution for the reagents.
CP/0/B/8100/OS Page 2 of 7 This contribution is subtracted from the rer.Jings of the standards and samples.
Compensation is not made for silica in the water as it was found in laboratory experiments to be negligible.
The absorbance values for these samples are plotted on graph paper depicting a theoretical standard curve developed from molar absorb-tivity values. Should the measured absorbance of the scandards exceed the theoretical curve, fresh reagents are prepared and the labware thoroughly cleaned.
1.3 Precision and Interferences The precision and accuracy of this method will be determined by Q-sum data.
Large amounts of iron, color, turbidity, sulfide, and phosphate are potential sources of positive interference.
1.4 Limits and Precautions This method is applicable for samples having a silica concentration in the range of 2 to 214 ppb.
Glass may contribute silica to the samples, therefore, care must be taken to avoid the use of glassware.
Eye protection, lab coats, and rubber gloves shall be used in handling concentrated hydrochloric acid.
All chemicals used are to be reagent grade.
1-amino-2-napthol-4-sulfonic acid should be refrigerated.
2.0 APPARUTUS 2.1 Spectrophotometer NOTE:
Allow instrument to warm up for thirty minutes prior to use.
2.2 Two matched 100 mm samT e cells l
2.3 Suitable number of 150 ml nalgene beakers 2.4 A 50 ml nalgene graduated cylinder 2.5 100 and 1000 ml nalgene volumetric flasks 2.6 A timing clock 2.7 One nalgene reagent dispenser to deliver 1.0 ml 2.8 Three nalgene reagent dispensers to deliver 2.0 ml 2.9 1000 pl Eppendorf pipet
~
CP/0/B/8100/08 Page 3 of 7 3.0 REAGENTS 3.1
" Silica Free" water for Preparation of Reagents The water used for reagent preparation is to be Super Q water.
3.2 Ammonium Molybdate, 10% W/V Dissolve 20.0 d 0.1 gm of ammonium molybdate, (NH46"7$4 0
4 0, a 2
200 5 ml of " silica free" water. Discard after week 3.3 Reducing Agent Dissolve 0.50 0.01 gm of 1-amino-2-napthol-4-sulfonic acid (NH H
1.0(Ing(OH)S0H)in50 1 ml of " silica free" water containing 3
0.I gm of sodium sulfite (Na SO After the sulfonic acid dissolves,addthesolutionverys$ow$y).and with constant stirring to a second solution containing 30.0 0.1 gm sodium bisulfite (NaHS0 )
3 in 100 ml of " silica free" water. Dilute to 200 5 ml with " silica free" water.
If precipitation has occured, filter the solution, at this time, through qualitative filter paper. Discard after two weeks.
3.4 0xalic Acid Solution Dissolve 15.0 ! 0.1 gm of oxalic acid (H C 0 2H 0) in 200 ! 5 ml of 3 3 4 3
" silica free" water.
This solution is stable in8efinitely.
3.5 Hydrochloric Acid, 50% V/V Dilute 1001 1 ml of concentrated hydrochlorii: acid (hcl) by addition of the acid to 100 2 1 ml of " silica free" water. This solution is stable indefinitely.
3.6 Silica Standard Solution, 100 ppm 3.6.1 In a 100.m1 nalgene voltmietrirflas1nida 46.73 mT (measured with a Class A 50 ml burette) of Fisher Certified Silicon Standard (1000 ppm Si) to about 700 ml of " silica free" water and dilute to volume.
This solution is stable for six months.
I NOTE:
If the Certified Silicon Standard is unavailable, the 100 ppm Silica Standard Solution may be made as per section 3.6.2.
t 3.6.2 Dir: solve 0.4777
.0001 g of reagent grade Sodium Silicate (Na,,Si0, 9H,0) in approximately 700 ml of " silica free" water j
in a 1000 mI nalgene volumetric flask.
Dilute to volume.
l This solution is stable for six months.
l 3.7 Silica Standard Solution, 10 ppm In a 1000 ml nalgene volumetric flask, dilute 1000 pl (1.0 ml) of 100 ppm silica standard (Section 3.6) to 1000 ml with " silica free" water.
NOTE:
Use this standard when generating a standard curve.
}.
~
CP/0/B/8200/08 Page 4 of 7 3.8 Silica Standard Solution, 25 ppb i
In a 100 ml nalgene volumetric flask, dilute 25 pl (0.025 ml) of 100 ppm silica standard (Section 3.6) to 100 ml with " silica free" water.
NOTE:
Use this standard for daily Q-Sum analyses.
4.0 PROCEDURE J
NOTE: Rinse all labware 3 times with " silica free" water before use.
4.1 Standard Preparation NOTE:
Generation of a standard curve is not required if this method is in current use; however, two 25 ppb standards will be run daily for Q-sum.
Generation of a new standard curve is required at least once a year.
4.1.1 Prepare a series of standards by diluting suitable volumes of the 10 ppm standard solution (Section 3.7) to 50 ml with " silica free" water in a 50 ml nalgene graduated cylinder. Transfer the contents of the 50 ml nalgene graduated cylinder to a clean 150 ml nalgene beaker.
pl of standard solution 10 ppm -
cone. pub 100 20 250 50 i
500 100 I
750-150 1000 200 l
4.1.2 Prepare three blanks as follows:
l 2
4.1.2.1 Color Blank #1 1
Add 50 ml 1 1.0 ml of " silica free" water to a 150 ml nalgene beaker I
4.1.2.2 Reagent Blank #2 Add 45 ml ! 1.0 ml of " silica free" water to a t-150 ml nalgene beaker 4.1.2.3 Reagent Blank #3 Add 50 ml 1 1.0 ml of " silica free" water to a 150 ml nalgene beaker.
i e.
.-m.e
---,-,,,....-,.-nm,,
---,,..-emg,v.,,
,,,,m,,,-w,
,,,-w,----,--
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-,--g
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CP/0/B/8100/08 Paga 5 of 7 4.1.3 Preparation of Color Blank #1 To the beaker containing the color blank add I ml
.5 ml of 50% V/V hydrochloric acid followed by the addition of 2 ml 2 0.5 ml of oxalic acid.
Thoroughly stir and add 2 ml 10.5 ml of ammonium molybdate, stir, and finally add 2 ml 0.5 ml of reducing agent.
Stir and allow to stand until needed.
NOTE:
The oxalic acid is added before the ammonium molybdate to prevent the formation of the molybdate-silicic acid complex.
4.1.4 Preparation of standards and reagent blank #3 4.1.4.1 To the beakers containing standards and reagent blank #3, add I ml 0.5 ml of 50% V/V bydrcchloric acid, followed by 2.0 ml 0.5 ml of ammonium molybdate. Mix and allow to stand for 5 minutes.
4.1.4.2 At the end of 5 minutes, add 2 ml 0.5 ml of oxalic acid, stir, and allow to stand for 1 minute.
4.1.4.3 Add I ml 0.5 ml of reducing agent, stir, and allow to stand for 10 minutes.
4.1.5 Preparation of Reagent Blank #2 4.1.5.1 To the beaker containing 45 ml of water, add double the normal volumes of reagents except for the reducing agent. Add 2 ml of hydrochloric acid, 4 ml of oxalic acid, 4 ml of ammonium molybdate and 2 ml of reducing agent.
4.1.5.2 Allow the appropriate reaction times after each l
addition as specified in Section 4.1.4.
t l
l NOTE:
Reagent Blank #2 may be prepared simultaneously with the standards and reagent blank #3.
4.2 Instrument Calibration 4.2.1 Adjust spectrophotometer to a wavelength of 815 nm.
4.2.2 Pour Color Blank #1 into a 100 mm sample cell, place in spectrophotometer, and set zero absorbance.
Care must be taken to clean all cell faces with tissue paper.
4.3 Determination of Standard Curve 4.3.1 Analyze Reagent Blank #2, Reagent Blank #3, and the standards, in order of increasing concentration, using a 100 mm sample cell.
The sample cell is to be rinsed between each analysis with the next sample to be analyzed. Recheck zero absorbance with Color Blank #1 before each sample.
CP/0/B/8100/08 Page 6 of 7 4.3.2 Correct the absorbance readings of all the standards by_sub-tracting the reagent absorbance value (Reagent Blank #2 absorbance - Reagent Blank #3 absorbance) from the standards' absorbance readings.
NOTE:
If the reagent absorbance value is greater than the absorbance value of Reagent Blank #3 or exceeds 0.05, the blanks are contaminated.
Stop the analysis, rewash all labware and start over.
4.3.3 Prepare a standard curve by plotting the corrected absorbance values versus concentration of the silica standards on a piece of graph paper which has the theoretical curve already plotted on it.
Should the measured values exceed the theoretical values, the data is invalid and fresh standard and/or reagents must be prepared.
The theoretical absorbance value for a 100 ppb standard is 0.390 and for a 200 ppb standard, 0.779.
4.4 Determination of Unknown Concentration 4.4.1 Transfer 50 ml 1.0 ml of each unknown sample to a clean 150 ml nalgene beaker.
4.4.2 Prepare three blanks as described in section 4.1.2.
4.4.3 Prepare a 25 ppb standard for Q-Sum analyses as described in section 3.8.
Transfer 50 ml of the standard to each of two 150 ml nalgene beakers.
t NOTE:
To be run once a day 4.4.4
. Prepare color blank #1 as per section 4.1.3.
i 4.4.5 To the beakers containing standards, samples, and reagent blank #3, add 1 m110.5 al of 50% V/V hydrochloric acid l
followed by the addition of 2 al 0.5 ml of ammoniur. moly-l bate. To Reagent Blank #2 add 2 al 1 0.5 ml of the 50% V/V hydrochloric acid followed by the addition of 4 ml 0.5 ml of ammonium molybdate.
Stir all beakers and allow to stand for 5 minutes.
4.4.6 After 5 minutes, add 2 ml : 0.5 ml of oxalic acid to beakers containing standards, samples, and reagent blank #3. Ad/.
4 ml 0.5 ml of oxalic acid to Reagent blank #2.
Stir and allow to stand 1 minute.
4.4.7 Add 2 ml 1 0.5 ml of reducing agent to beakers containing samples, standards, reagent blank #2 and reagent blank #3.
i Stir and allow to stand 10 minutes before analyzing.
4.4.8 Calibrate Spectrophotometer as per section 4.2.
CP/0/B/8100/08 Page 7 of 7 4.4.9 Analyze Reagent Blank #2, Reagent Blank #3, standards, and samples using a 100 mm cell.
The sample cell is to be rinsed between each analysis with the next sample to be analyzed.
Recheck zero absorbance with Color Blank #1 before each sample.
4.4.10 Correct the absorbance readings of the standards and samples by subtracting the reagent absorbance value (Reagent Blank
- 2 absorbance - Reagent Blank #3 absorbance) from the measured absorbances.
NOTE:
If the reagent absorbance value is greater than the absorbance value of Reagent Blank #3 or exceeds 0.05 absorbance units, the blanks are contaminated.
Stop the analy: tis, rewash all labware and start oVer.
4.4.11 Determine the concentration e unknown sample (s) by comparing the sample absorbat _
- h the standard curve.
5.0 REFERENCES
5.1 American Society for Testing and Materials, 1978 Book of ASTM Standards, Part 31, D 859-68, Pages 468-469.
5.2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, 1975, Part 426B, Pages 487-490.
5.3 McGuire Nuclear Staion Chemistry Procedure CP/0/B/8100/20A.
l 5.4 Oconee Nuclear Station Chemistry Procedure CP/0/B/300/18.
5.5 Report on the Determination of Low Level Silica in High Purity Water, J. B. Wilson, August, 1981.
6.0 ENCLOSURE 6.1 Theoretical Plot of Absorbance vs. Concentration using the Molar Absorbtivity for Molybdenum Blue.
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Enclosure.6.1
-..' ' Typical Standard Curve I
for Silica CP/0/B/8100/08 i
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. Thsoretical-Curve 1
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