IR 05000237/1988028
| ML17201M280 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/05/1989 |
| From: | Holtzman R, Schumacher M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML17201M279 | List: |
| References | |
| 50-237-88-28, 50-249-88-29, NUDOCS 8901130098 | |
| Download: ML17201M280 (12) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION III
Reports N /88028(DRSS); 50-249/S8029(DRSS)
Docket No ; 50-249 Licenses N DRP~l9; DRP-25 Licensee:
Commonwealth Edison_ Company Post Office Box 767 Chicago, IL 60690 Facility Name:
Dresden Nuclear Power Station, Units 2 and 3 Inspection At; Dresd~n Site, Morris, Illinois Inspection Conducted:
December 5-9, 1988 (Onsite)
December 19, 1988 (Telephone k.1@.,
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Irispector:
R. B. H. t an
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Approved By:
M. C. Schumacher, Chief Radiological Controls and Chemistry Section Inspection Summary discussions)
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/47/-5 Date Inspection on December 5-9 and 19, 1988 (Reports No. 50-237/88028(DRSS);
50-249/88029(DRSS))
Areas Inseected:
Routine unannounced inspection of:
(1) the chemistry program, including procedures, organization, and training (IP 84750);
(2) reactor systems water quality and chemical control programs (IP 84750);
(3) quality assurance/quality control program in the laboratory (IP 84750);
and (4) nonradiolgical confirmatory measurements (IP 79701).
Results:
The licensee has a hydrogen water chemistry (HWC) program in Unit 2, which substantially improves the RCS water quality, but results in increased radiation levels to the turbine*building and external to the plan However, the Unit 2 Electrochemical Potential (ECP) monitor necessary to optimize the HWC for minimum radiation dose is presently inoperabl The licensee is planning to replace this instrumentation before 199 The water chemistry control program generally conforms to the the EPRI BWR Owners Guideline Extensive use was made of chemistry parameter trend chart The nonradiological chemistry confirmatory measurement results were fai Most of the problems were*
resolved*prior to the end of the inspectio The laboratory has a good QA/QC program for analytical measurements, which is being developed furthe The staff appeared to be knowledgeable and competen No violations or deviations were identifie *
DETAILS Persons Contacted 1E. D. Eenigenburg, Station Manager, Dresden Nuclear Power Station (DNPS)
1C. W. Schroeder, Services Superintendent, DNPS 1J. Brunner, Assistant Superintendent-Tech Services, DNPS 1 K. Peterman, Regulatory Assurance Supervisor, DNPS 1T. J. Lewis, Regulatory Assurance Staff, DNPS 1, 2D. Morey, Chemistry Services Supervisor, DNPS D. Saccomundo, Health Physics Supervisor, DNPS D. Malauskas, Operational Group Leader, Chemistry, DNPS R. Slachniak, Assistant Tech Staff Supervisor, DNPS J. Isom,_ Analytical Chemist, Contractor J. Rund, Auxiliary Chemist, DNPS R. Berg, Engineering Assistant, QA Coordinator, DNPS J. Ruettinger, Chemistry Laboratory Foreman, DNPS D. Rink, Engineering Assistant~ Chemical Control, DNPS M. Wood, Chemistry Technician (CT), DNPS M. Carroll, CT, DNPS P. Bernier, CT, DNPS 1D. E. Jones, Project Inspector, Region III, NRC The inspector also interviewed other licensee personnel in various departments in the course of the inspectio Present at the plant exit interview on December 9, 198 Telephone conversations held on December 19, 198.
Licensee Action on Previous Inspection Findings (Closed) Open Item Nos. (50-237/88003-02; 50-249/88003-02):
Laboratory to implement control charts on the ion chromatographic and boron analyse The laboratory has implemented control charts for the high-level boron analysis for the Standby Liquid Control tanks and analyses done on the IC, including fluoride, high and low-level chloride, sulfate and sodiu These appear to be operating satisfactoril (Closed) Deen Item (50-237/88019-02; 50-249/88020-02):
For the HRSS of both units, the licensee was to verify that a liquid sample was representative of the RCS, to verify that the sizes of the diluter valves RC-DV-1 were as stated on the panels, and to determine a method of verifying the volume of the containment gas sampling valve The licensee verified the representativeness of the samples by comparison of the iodine-131 dose equivalents of samples collected from the normal RCS sampling location in the reactor with those of samples from the respective HRSS hood They found dose equivalents
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of 1.i6 E-4 and 1.37 E-4 µCi/g for the Unit 2 HRSS and Rx hoods, respectiveJy, and 1.80 E-4 and 2.00 E-4 µCi/g for the respective sampling points on Unit Within the uncertainties of this method, these results show the HRSS samples to be representative of the reactor coolan *
The licensee tested the diluter valves by trapping soluiions containing 4000 ppm each of chloride and nitrite in the valves and then flushing the valves with 100 ml of deionized water. The dilution factors calculated from the analyte concentrations determined on the IC before and after dilution, were then used to determine the valve volume The values were within 15% of those previously determined.
. The licensee ~ill return the containment air sample panel gas partioners to the man~facturer to determine the minimum volume of the gas collected by the valve The instrument will also be rebuilt and modernize They expect to complete this work by February 198 This item is considered closed; completion of this work will be followed in subsequent inspections under Open Item Nos. (50-237/88028-01; 50-249/88029-01). Management Controls, Organization and Training (IP 84750)
The Chemistry Group has been significantly reorganized since. the previous inspection in this area. 1 The Rad/Chem Department was separated into the Chemistry and Health Physics Departments and the Chemistry Department Supervisor (formerly the Lead Chemist) now reports to the Assistant Superintendent-Tech Service Reporting to the Supervisor are the Operational Group and Technical Group Leaders, supported by three and four staff members, respectively, a Laboratory Foreman, who directly supervises the laboratory, and a Chemistry Foreman who mainly does administrative work, such as laboratory schedulin Since October 1988, 14 technicians have been permanently assigned to the Department under the new job title of Chemistry Technicians (CT).
They are all qualified as Rad/Chem Technicians under the standard ANSI Nl8.1-197 The training and requalification programs for the CTs are being revised to conform to the new-chemistry progra The staffing appears to be adequate to perform the required chemistry for plant operation This separation of technician duties should substantially increase technician proficiency, and reduce the training and retraining work loads of the staf *
No violations or deviations were identifie.
Water Chemistry Control Program (IP 84750) General Aspects The inspector reviewed aspects of the water chemistry control program in the plan The licensee 1s water chemistry program 1Region III Inspection Reports No. (50-237/88003; 50-249/88003).
- generally conforms to the EPRI BWR Owners Guidelines and is required by the corporate directive NSDD-S17; 11 BWR Water Chemistry Control
Progra _
-
The licensee maintains trend charts on the various parameters, including silica and conductivity in the reactor cleanup system, nitrites in the HRSS~ RBCCW, and TBCCW, and dissolved oxygen, chloride, sulfate, silica, and conductivity in the reactor coolant syste There are also charts and monthly reports on percentage of time and hours Out-of-Specification (OOS) for both the reactor-related and auxiliary system They also plot the INPO CPI (Chemistry Performance Index), which isa sum of ratios of a set o chemistry parameter values relative* to those of the EPRI guideline This appears to be a more-sensitive and accurate measure of chemistry
- quality than the OOS inde The trend charts show goals for this plant and the averages for all BWR The plant maintained generally low levels of contaminahts in the ~ater; the CPI indicates that the RCS water quality in Unit 2 whiCh uses Hydrogen Water Chemistry (HWC),
is better than in Unit 3 which does no The Makeup Demineralizer system is being rebuilt and is scheduled for completion by the end of 198 It will improve the ease of operation and the quality of water it supplies to the reactor The makeup water is presently supplied by a portable (trailer)
vendor syste There appear to be good safeguards in the system to prevent contamination of the RCS in case of malfunctioning of the vendor system, including a conductivity alarm in the control r,aom, directing the water to intermediate tanks before the water enters the RCS, and operating procedures to control the activitie Hydrogen Water Chemistry, Unit 2 The inspector reviewed the -hydrogen water chemistry (HWC) in Unit 2 in which hydrogen is added to the feedwater to reduce oxygen levels in the RCS with the purpose of limiting corrosio Licensee representatives stated that this use over about five years has improved the water chemistry, as seen by substantially reduced dissolved oxygen concentrations and decreased water conductivity, and it appears to have halted the growth of previously-observed cracks in the recirculation pipe The hydrogen flow rate was originally optimized after installation to maintain the minimu~
rate that will prevent corrosion by adjusting the electrochemical potential (ECP) in a recirculation pipe sampling point to below-250 mV mea_sured against a standard hydrogen electrod One consequence of HWC, however, is substantially increased radiation levels in the turbine, and measureably higher radiation levels in the turbine building and in the plant environ The cause is enh~nced volatility of N-16 produced in the reactor water during hydrogen additio Exposure rates from N-16 at about 2500 feet from the plant appear to run several µR/hr (EPRI Report NP 4011, 11 Radiological Effects of Hydrogen Water Chemi stri
, 1985).
Since the radiation levels from the turbine appear to be proportional to the H2 flow rates, these rates should be optimized to be as low as possible, while maintaining the proper EC This was done when the system was installed in 1983, but presently the ECP monito~ is inoperable and it is not known if the flow rates are still optimal from an ALARA perspectiv The licensee is planning to install a new ECP and crack-growth monito Licensee representatives expected
- budget authorization in January 1989 and estimated the completion date to be August 199 The ALARA aspects of HWC will reviewed in an upcoming inspection under Open Item No. (50-237/88028-02).
No violations or deviations were identifie.
Chemical Control Program (IP 84759) The inspector reviewed the chemical control program that applies controls to the use of chemicals in the plant, implemented by th Dresden Administrative Procedure~:
OAP 16-1, 11 Station Chemical Control Program," Revision 4, July 1987,
OAP 16-2, "Disposition of Chemicals and.Chemical Products as Waste, 11 Revision 0, August 1984, and
OAP 16-3, "Station Chemical Control Program:
Special Processes,"
Revision 0, August 1984.
This program has a coordinator who actively oversees the activities to limit the chemicals in the plant that may damage the equipment or enter the RCS, especially organic chemicals that break down to acids in radiation fields:
This appears to have resulted in improvements in reactor water chemistr The allowed chemicals are listed, maintained by the stockroom and carefully regulated by the coordinato Waivers are allowed on the use of restricted chemicals that are necessary after the coordinator reviews them and trains the users in their proper handlin This system '
appears to be very useful in improving the maintenance of plant system qualit No violations or deviations were identifie Implementation of the Chemistry Program (IP 84750)
The inspector reviewed the chemistry programs, including physical facilities and laboratory operations. This year the laboratory operation is greatly improved over that in previous years; the hot laboratory was recently rebuilt and refurbished with new furniture, and the refurbishing of the cold laboratory is almost complete Housekeeping and bench space were adequate for the analyses performe The laboratories instrumentation has been improved and now has a computer-operated four unit Dionex Ion Chromatographic system, a Spectronic 1201 UV/visible Spectrophotometer with a long-path (10-cm) sample cell for improved sensitivity of silica
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analyses, a Perkin-Elmer Model 5000 Atomic Absorption Spectrophotometer (AAS), and total organic carbon (TOC) analyzer that is both more sensitive and more accurate than the previous uni The laboratory has also added a CEM MOS 810 Microwave.Digestion Unit to better dissolv~ filt~r paper samples in a digestion bomb with pressurized high temperat~re aci The inspector observed several CTs analyze the confirmatory measurements samples by titration; AAS, and ion chromatograph They appeared to be generally. knowledgeable about the work, and followed procedure They were more confident in performing these analyses than those observed in previous inspection Overall, the laboratory appeared to be adequate for the proper operation of the plant and to be operatin*g satisfactoril No violations or deviations were identifie. * Nonradiological Confirmatory Measurements (IP 79701)
The inspector submitted chemistry. samples to the licensee for analyses as part of a program to evaluate the laboratory's capabilities to monitor -
nonradiological _chemistry parameters in various plant systems with respect to various Technical Specification and other regulatory and administrative requirement These samples had been prepared, standardized, and periodically reanalyzed (to ch~ck for stability) for the NRC by the Safety and Environmental Protection Division of Brookhaven National Laboratory (BNL).
The* samples were analyzed by the licensee using routine methods and equipmen The samp 1 es were diluted by 1 i censee personne 1 as necessary to bring the concentrations within the ranges normally analyzed by the laboratory, and run in triplicate in a manner similar to that of routine sample The results are presented in Table 1 and the criteria for agreement in Attachment These criteria.fo~ agreemant are based on com~arisons of the mean values and estimates of the standard deviations (SD) of the mea~urements. Consideration was given to the fact that the uncertaintie~
(SD) of the licensee's results were not necessarily representative of the laboratory's because they were obtained by one analyst over a short period of tim Consequently when the licensee SD was less than that of BNL, and a disagreement resulted, the BNL value was substituted for that of the licensee in calculating the SD of the ratio Z (S in Attachment 1).
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z The licensee also prepared a sample of reactor coolant water to be split with BNL. *This was spiked with anion analytes, fluoride, chloride and sulfate, supp 1 i ed by the inspecto The licensee wi 11 determine the concentrations of the analytes and the results will be sent to Region III for comparison with the values determined by BN This will be followed under the Open Item Nos. (50-237/88028-03; 50-249/88029-02).
The licensee analyzed eight materials at three concentrations each, plus silica at two concentration Of the initial 26 analyses, only 11 (42%)
were in agreement with the BNL value The disagreements included all
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three chloride and iron samples, two each of fluoride and chromium, and one each of the sulfate, nickel and silica concentration value While the boron values had a substantial bias of about -3% {l~rge for this type of analysis), the results are consistent with those observed in this program in other laboratories. This laboratory used an autotitrator with a dead-end pH point with 0.1 N NaOH titrant standardized against potassium acid phthalate and checked with a 1000 ppm boron standar solutio The inspector is looking into resolving these discrepancie The generally high biases on the anion analyses done on the ion chromatograph (IC) indicated that the actual concentrations of the calibration standards were lower than state Th~ inspector's.
discussions revealed that the standards were made from undried solid reagents taken directly from the bottles~ The licens~e then made new standard solutions after drying as recommended by the ASTM IC procedure, i.e. r the NaCl wa~ dried at 600°C and the other reagents at 110° These then resulted in agreements (
11reruns 11 in Table 1), with substantially improved biase The licensee stated that the IC procedure will be revised immediately to include the proper proper drying methods for the standards and they will also use liquid (commercial) anion standards in their procedures as performance check standards to provide independent checks on the standardizatio The laboratory reran the metals samples with the help of a chemist from the corporate Technical Support Center.. The causes of the difficulties were not ascertained, but the results were improved to 10 agreements in 12 analyses and biases were reduce Licensee representatives noted the inspectors comments that possible improvement might result by fitting a quadratic, rather than a straight line curve to the multi-point calibration dat The iicensee has the basic elements of a good QA/QC program; it utilizes mul t i-poi_nt ca 1 i brat ions on the AAS, IC and spectrophotometer, independent performance check standards, and control charts with statistically-derived control limit However, the confirmatory measurements results revealed some weaknesses in the program (Section 8). Resolution of these problems, revision of the IC procedure, resolution of the discrepancies with the AAS analyses, and comparison of the results of these analyse in the corporate interl aboratory program will be fo 11 owed under Open Item Nos. (50-237/88028-04; 50-249/88029-03).
No violations or deviations were identifie.. Implementation of the QA/QC Program in the Chemistry Laboratory (IP 84750)
The inspector reviewed the nonradiological QA/QC program in the laborator The program is required by the corporate QC manual, Nuclear Operation Division Chemistry Quality Control Program Manual, Revision March 15, 1988. * It requires the use of control charts with statistically-derived control limits at the two-sigma level, multi-point calibrations, where.
applicable, and a definite minimum frequency of instrumental calibration They have control charts for most analyses, including those for the IC analyses of high and low-level chloride and sulfate, fluoride, nitrate, nitrite, and sodium, for the AAS analyses of iron, copper, and chromium, for the UV/vis spectrophotometric analysis of silica, and for the titration analysis of boro However, while the laboratory program has the basic elements of a good QA/QC program, it is still under development, and appears to have some deficiencies (Section 6, this report).
The supervisors do not check for problems in the analyses unless the performance check standard results are out of the control limits; e.g., several results in a row on one side of the mean value line indicates a change in conditions and may call for a recalibratio The !Cs are recalibrated only if there appears to be a defect, based on control chart or other data; it appears to the inspector that the IC should be calibrated (or normalized) at one point, at least daily, si nee some parts -of the instrument may be sensitive to room temperature variation, especially the conductivity cell detecto Infrequent calibrations for an unstable instrument may result in control limits that do*not truly reflect the instrument capabilitie Licensee representatives noted that they will check these effects by tracking the peak areas of the performance standards and applying controlled temperature changes to the detector The technician performance test program was reviewe The technicians were required to do blind samples prior to starting their tours in the laboratory for the analyses they would be doing during the tou These samples included pH, silica, chloride, sulfate, total organic carbon, and the metals, iron, copper, nickel and chromium analyses, with acceptance criteria based on 2-sigma form the c.ontrol chart This program is beirig revised to conform to the technicians being permanently assigned to the laborator They will each be tested on a set of samples semiannually (the QA manual.requires only annual testing) on approximately the same procedures as befor The licensee results in the corporate interlaboratory comparison improved over the first three quarters of this year.according to the performance standard defined as the fraction of the results within 10% of the calculated valu The licensee had all the values within 10% in the second and about 80% in the t_hi rd quarter compared to about 50 % in the first quarte This appears to be somewhat better than the other BWR stations in the grou The inspector told licensee representatives that the QA/QC program has progressed well and appears _to be a good program as planned. *Further progress of this program will be followed in subsequent routine chemistry inspection No violations or deviations were identifie.) Open Items Open items are matters which have been discussed with the licensee, which
- will be reviewed further by the inspector, and which involve some action on the part of the NRC or licensee, or bot Open items disclosed during the inspection are discussed in Sections 2, 4 and *
.1 Exit Interview The scope and findings of the inspection were reviewed with licensee representatives (Section 1) at the concl us,ion of the inspection on December 9, 1988, and in telephone discussions on December 19, 1988, with the Chemistry Department Supervisor. * The inspector di scu.ssed the Open Items in Section 2 and observations on the quality control program and the confirmatory measurement He noted the progress in the QA/QC program since the previous inspectio The inspector discussed HWC in Unit 2, which results in possible high radiation levels to the plant environs, and the lack of an ECP monitor to optimize the.hydrogen flow and radiation leve He expressed some concerns about the lead time in replacing the monito The ALARA will be reviewed in an upcoming inspectio During the exit interview, the inspector discussed the likely informational*
content of the inspection report with regard to documents or processes reviewed by the inspector during the inspectio Licensee representatives did not identify any such documents or processes as proprietar Attachments: Table 1, Nonradiological Interlaboratory Test Results, December 5-9, 1988 Attachment 1; Criteria for Comparing Analytical Measurements (Nonradiological)
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TABLE 1 Nonradiological Interlaboratory Test Results Dresden Nuclear Generating Station, Units 1 and 2 December 5-9, 1988 Analyte Analys~ Dilu-
.NRC Licensee Ratio Comparisoric Method ti on, l:x Y +/- SD X +/- SD Z +/- SD +/- 2 SD Concentration, ppb Chloride IC 9.25
+/- 0.05 10. 6 +/-.146 +/- 0. 044 D
- I
!
18.6 +/- 0.3.8 +/-.330 +/- 0.078 D
3 +/-.1 +/- 1. 0 1.154 +/- 0. 032 D
(rerun)
9.25 +/- 0.05 9.10 +/- 0.40 0.984 +/- 0.044 A
II 18.6 +/- 0.30 21. 5 +/- ],. 9 1.155 +/- 0.104 A
II 38.2 +/-.4 +/-.058 +/- 0.031 A
Fiuoride IC 11. 2 +/- 1. 0 10.4 +/-.929 +/- 0.112 A
21. 2 +/-. 25.1 +/- 1. 2 1.184 +/- 0. 061 D
41.4 +/-.3 +/- 1. 0.
1. 094 +/- 0. 034 D
(rerun)
11.2 +/- 1. 0 10.2 +/- 0.38 0. +/- 0.089 A
(rerun)
21. l
+/-. 9 +/- 0. 2*
1. 035 +/- 0. 022
.A (rerun)
41.4 +/-. 5 +/- 1. 0 1. 002 +/- 0. 033 A
Sulfate IC 9.75 +/- 0.70 11.3 +/- 1. 0 1.159 +/- 0.132 A
19.2 +/-.6
+/- 1. 3 1.177 +/- 0.109 A
3 +/- 1. 2 46.5 +/-.192 +/- 0. 041 D*
(rerun)
9.75 +/- 0.70 10. 6 +/-. 087 +/- 0. 089 A
11*
19.2 +/- 1.45 20.4 +/-. 062 +/- 0. 088 A
II 3 +/-.1 +/-.. 028 +/- 0. 032 A
Fe AA/FL 930
+/- 25 1090
+/- 25 1.172 +/- 0.041 D*
1990
+/- 25 2120
+/- 10 1. 065 +/- 0. 019 D*
2340
+/- 60 2565
+/- 20 1. 096 +/- 0. 040 D*
{rerun)
.930
+/- 25
. 1083
+/- 10 1.165 +/- 0. 044 D*
II 1990
+/- 25 2055
+/- 20 1. 033 +/- 0. 016 A
II 2340
+/- 60 2468
+/- 30 1. 055 +/- 0. 030 A
Cu AA/FL 1000
+/- 15 1040
+/- 10 1. 040 +/- 0. 022 A*
2015
+/- 75 2075
+/- 20 1.030 +/- 0.040 A
2400
+/- 60 2475
+/- 20 1.031 +/- 0.027 A
(rerun)
1000
+/- 15 1024
+/- 10 1. 024 +/- 0. 018 A
2015
+/- 75 2019
+/- 50 1. 002 +/- 0. 045 A
2400
+/- 60 2411
+/- 60 1.005 +/- 0.035 A
Ni AA/FL 1015
+/- 30 1140
+/- 0 1.123 +/- 0. 044 D*
2085
+/- 35 2160
+/- 10 1. 036 +/- 0. 018 A*
2420
+/- 100 2560
+/- 0 1. 058 +/- 0. 044 A
(rerun)
1015
. +/- 30 1106
+/- 3. 090 +/- 0. 045 A*
2085
+/- 35 2050
+/- 120 0.983 +/- 0.060 A
2420
+/- 100 2506
+/-. 21 1. 036 +/- 0. 044 A
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Cr AA/FL 990
+/- 25 1140
+/-
1.152 +/- 0. 041 1925
+/- 25 2120
+/- 10 1.101 +/- 0. 020 2320
+/- 40 2420
+/-
1.043 +/- 0.025 (rerun)
990
+/- 25 1040
+/- 10 1.051 +/- 0.028 II 1925
+/- 25 1932
+/- 10 1. 004 +/- 0. 014 II 2320
+/- 40 2110
+/-
0.909 +/- 0.022 Silica Spec 5 +/- 2 52.2 +/-. 004 +/- 0. 039 7 +/- 1 86.2 +/-.098 +/- 0.020 Concentration 2 EEm B
Titr * 1040
+/- 10 1000
+/- 1 0.962 +/- 0.013 3089
+/- 41 2960
+/- 3 0.958 +/- 0.018 5000
+/- 90 4895
+/- 5 0.979 +/- 0.018 Value+/- standard deviation (SD); BNL did 6-9 analyses per lo The licensee analyses did 3 analyses on each sampl Analytical methods:
Titr _- titration * A = Agreement D = Disagreement IC
- Ion chromatography Spec - Spectrophotometric AA/FL-Atomic absorption Spectroscopy (flame)
- Substituted the BNL uncertainty for licensee 1s uncertaint D*
D*
A*
A A
D*
A D*
D*
D*
A
ATTACHMENT 1 Criteria for Comparing Analytical Measurements This attachment provides criteria for comparing results of the capability test The acceptance limits are based on the uncertainty (standard deviation) of the ratio of the licensee's mean value (X) to the NRC mean value (Y), where (1) Z = X/Y is the ratio, and (2) S is the uncertainty of the ratio determined from the ptopagation of the uncertainties of licensee's mean value, Sx, and of the NRC 1s mean value, SY. 1 Thus,
S/ S/
~ so that-rr = xz- + yr'
S =Z* ~+l (52 52J~
z x2 y2 The results are considered to be in agreement when the bias in the ratio (absolute value of difference between unity and the ratio) is less than or equal to twice the uncertainty in the ratio,.
National Council on Radiation Protection and Measurements, A Handbook of Radioactivit~ Measurements Procedures, NCRP Report No. 58, Second Ed1tlon, 1985, Pages 322-326 (see Page 324).
4/6/87