ML20198H298
| ML20198H298 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 12/17/1998 |
| From: | Terry C, Walker R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20138M399 | List: |
| References | |
| TXX-98274, NUDOCS 9812290303 | |
| Download: ML20198H298 (130) | |
Text
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' nlELECTRIC
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L c. w w'7 ' December 17,1998 Senior Mce President
& PrincipalNuclear OBicer l
U. S.- Nuclear Regulatory Commission l Attn: Document Control Desk l Washington, DC 20555 L
l
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) y ,
DOCKET NOS. 50-445 AND 50-446
- SUBMITTAL OF RESPONSES TO REQUEST FOR
. ADDITIONAL INFORMATION REGARDING CALDON TOPICAL REPORT ER-80P lL REF: 1) TU Electric letter, logged TXX-98180, from C. L. Terry to the NRC dated July 18,1998
l
. Gentlemen .
Please find enclosed responses to a request for additionalinformation (Reference 1) regarding topical report ER-80P," Improving Thermal Power Accuracy and Plant Safety While Increasing Operating Power Level Using the LEFM/ " System." TU Electric has referenced this topical report in support of an exemption request (Reference 2) to specific criteria contained in 10CFR50, Appendix K. TU Electric is preparing Operating License and Technical Specification amendment requests based l on information contained in the subject topical report. Since some of the responses
- contain information proprietary to Caldon, Enclosure i provides a non proprietary version of the responses to the questions while Enclosure 2 provides a proprietary
. version.
L As this submittal contains information proprietary to Caldon, it is supported by an L affidavit signed by Caldon, the owner of the information. The affidavit sets forth the L ~ basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph L (b)(4) of 10CFR2.790 of the Commission's regulations. ..
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Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting l
1 TOPICAL REPORT: Improving Thermal Power Accuracy and Plant Safety While Increasing Operating Power Level Using the LEFM/ System as Applied to Comanche Peak December 15,1998 NON-PROPRIETARY VERSION
TXX-98274 Page 2 of 2 The Caldon Application for Withholding, CAW-98-01, Accompanying Affidavit, and Proprietary information Notice are enclosed.
Accordingly, it is respectfully requested that the information which is proprietary to Caldon be withheld from public disclosure in accordance with 10CFR2.790 of the Commission's regulations. Correspondence with respect to the proprietary aspects of the Application for Withholding or the supporting Caldon affidavit should reference CAW-98-01 and should be addressed to Calvin R. Hastings, President and CEO, Caldon incorporated,1070 Banksville Avenue, Pittsburgh, Pennsylvania 15216.
This communication contains no new commitments regarding CPSES Units 1 and 2.
Sincerely,
$h.
C. L. Terry By: @
R. D. #alker Regulatory Affairs Manager JDS/jds enclosures: 1) " Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting," (Non-Proprietary) December 15, 1998
- 2) " Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting," (Proprietary) December 15,1998 c- E. W. Merschoff, Region IV J. l. Tapia, Region IV T. J. Polich, NRR Resident inspectors, CPSES i
I b - @_ h .k._-2 E:h EAI2 e e a: =en a Caldon,Inc.
December 15,1998 1070 BanksviHe Avenue Pittsburgh, PA 15216 412 341-9920 Tel Document Control Desk U.S. Nuclear Regulatory Commission
[9ne Washington, DC . 20555 Attention: Mr. Tom Polich APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM ?UBLIC DISCLOSURE
Subject:
Responses to NRC Additional Staff Questions concerning Topical Report, " Improving Thermal Power Accuracy and Plant Safety While Increasing Thermal Power Level Using the LEFM/ System,"
(Proprietary), December 15,1998.
Dear Mr. Polich,
The proprietary information for which withholding is being requested in the above-referenced document is further identified in Affidavit CAW-98-03 signed by the owner of the proprietary information, Caldon, Inc. The affidavit which accompanies this letter, sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of 10 CFR Sectioa 2.790 of the Commission's regulations.
Accordingly, this letter authorizes the utilization of the accompanying Affidavit by TU Electric.
Correspondence with respect to the proprietary of the application or withholding or the Caldon affidavit should reference this letter, CAW-98-03, and should be addressed to the
. undersigned.
I Very truly yours - .
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Calvin R. Hastings adl '
. President and CEO Enclosures
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December 15,1998 CAW-98-03 )
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AFFIDAVIT I L
' COMMONWEALTH OF PENNSYLVANIA:
SS COUNTY OF ALLEGHENY: )
Before me, the undersigned authority, personally appeared Calvin R. Hastings, who, being by me duly sworn according to law, deposes and says that he is authorized to execute this Affidavit on behalf of Caldon, Inc. ("Caldon") and that the averments of fact set forth in this Affidavit are true and correct to the best of his knowledge, information, and belief:
I bbE f Ahm Calvin R. Hastings, President and CEO Caldon, Inc. i Sworn to and subscribed before me this /bfb dayof
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- l. I am the President and CEO of Caldon, Inc. and as such, I have been specifically delegated the function of reviewing the proprietary information sought to be withheld from public disclosure in connection with nuclear power plant licensing and rulemaking proceedings, and am authorized to apply for its withholding on behalf of Caldon.
- 2. I am making this Affidavit in conformance with the provisions of 10 CFR Section 2.790 of the Commission's regulations and in conjunction with the Caldon application for
,ithholding accompanying this Affidavit.
- 3. I have personal knowledge of the criteria and procedures utilized by Caldon in designated
)
information as a trade secret, privileged or as confidential commercial or financial I infonnation. I l
- 4. Pursuant to the provisions of paragraph (b) (4) of Section 2.790 of the Commission's )
l regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.
(i) The infonnation sought to be withheld from public disclosure is owned and has been held in confidence by Caldon.
(ii) The infonnation is of a type customarily held in confidence by Caldon and not customarily disclosed to the public. Caldon has a rational basis for determining the types ofinformation customarily held in confidence by it and, in that connection, utilizes a systen to detemme when and whether to hold certain types ofinformation in confidence. The application of that system and the substance of that system constitutes Caldon policy and provides the rational basis required.
i Under that system, infonnation is held in confidence ifit falls in one or more of several types, the release of which might result in the loss of an existing or potential advantage, as follows:
(a) The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention ofits use by ,
any of Caldon's competitors without license from Caldon constitutes a competitive economic advantage over other companies.
l (b) It consists of supporting data, including test data, relative to a process (or 2
component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage, e.g., by optimization or improved marketability.
(c) Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar product.
(d) It reveals cost or price information, production capacities, budget levels, or commercial strategies of Caldon, its customer or suppliers.
(e) It reveals aspects of past, present or fbture Caldon or customer funded developn ent plans and programs of potential customer value to Caldon.
(f) It contains patentable ideas, for which patent protection may be desirable.
There are sound policy reasons behind the Caldon system which include the following:
(a) The use of such information by Caldon gives Caldon a competitive advantage over its competitors. It is, therefore, withheld from disclosure to protect the Caldon competitive position.
(b) It is information which is marketable in many ways. The extent to which such information is available to competitors diminishes the Caldon ability to sell products or services involving the use of the information.
(c) Use by our competitor would put Caldon at a competitive disadvantage by reducing his expenditure of resources at our expense.
(d) Each component of proprietary information pertinent to a particular competitive advantage is potentially as valuable as the total competitive sdvantage. If competitors acquire components of proprietary information, any one component may be the key to the entire puzzle, thereby depriving Caldon of a competitive advantage.
(e) Unrestricted disclosure would jeopardize the position of prominence of Caldon in the world market, and thereby give a market advantage to the competition of those countries.
(f) The Caldon capacity to invest corporate assets in research and development depends upon the success in obtaining and maintaining a competitive advantage.
(iii) The information is being transmitted to the Commission in confidence, and, under the 3
provisions of 10 CFR Section 2.790, it is to be received in confidence by the Commission.
(iv) The information sought to be protected is not available in public sources or available information has not been previously employed in the same manner or method to the best of our knowledge and belief.
(v) The proprietary information sought to be withheld in this submittal is that which is appropriately marked in the " Responses and further clarifications to NRC Questions from September 29,1998 meeting, Topical Report, ' Improving Thermal Power Accuracy and Plant Safety While Increasing Operating Power Level Using the LEFM/
System', as Applied to Comanche Peak, December 15,1998, Proprietary Version" and is being transmitted by TU Electric letter and Application for Withholding Proprietary Information from Public Disclosure, to the Document Control Desk, Attention, Mr. Tim Polich. This information is submitted for use by TU Electric for the Comanche Peak Nuclear Plants and is expected to be applicable in other license submittals for justification of the use of the Caldon Leading Edge Flow Meter (LEFM/) to increase reactor plants' thermal power. (A separate document " Responses and further clarifications to NRC Questions from September 29,1998 meeting, Topical Report,
' Improving Thennal Power Accuracy and Plant Safety While Increasing Operating Power Level Using the LEFM/ System', as Applied to Comanche Peak, December 15, 1998, Non-Proprietary Version" is also being submitted which extracts the non-proprietary elements of the proprietary responses, and which non-proprietary document may be made publicly available.)
This information is part of that which will enable Caldon to:
(a) Demonstrate the design of the LEFM/ and accuracy of the LEFM/ flow and temperature measurements, as well as the improved calorimetric thermal power accuracy based on the LEFM/ measurements.
(b) Demonstrate the reliability of the LEFM/ based on design features and on compiled field experience data.
Establish technical and licensing approaches for the application of the l (c) improved accuracy of this method towant increasing thermal power.
(d) Assist customers in obtaining NRC approval for increases in thermal power based on appropriate use of the LEFM/ for calorimetric power measurement.
4
Further this infomiation has substantial commercial value as follows: ,
1
)
(a) Caldon plans to sell the LEFM/ and use of similar information to its customers for purposes of meeting NRC requirements for operation at I increased thermal power. )
(b) Caldon can sell support and defense of the technology to its customers in the licensing process.
Public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Caldon because it would enhance the ability of competitors to provide similar flow and temperature measurement systems and licensing defense services for commercial power reactors without commensurate expenses. Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without the right to use the information.
The development of the technology described in part by the information is the result of applying the results of many years of experience in an intensive Caldon effort and the expenditure of a considerable sum of money.
In order for competitors of Caldon to duplicate this information, similar products would have to be developed, similar technical programs would have to be performed, and a significant manpower effort, having the requisite talent and experience, would have to be expended for developing analytical methods and receiving NRC approval for those methods.
Further the deponent sayeth not.
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4 NRC Staff Questions
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- 1. Describe Caldon's understanding of the background for 1.02 being ascribedjust for instrument .
uncertainty in power determination.
- 2. On page 5-2 of the Topical Report, explain the justification for the use of PTC-6.
- 3. Describe how the LEFM/ is used in calorimetric power determinations.
- 4. Address LER 94-001-01 which applied to older LEFM models and how the event would be avoided in the LEFM/.
- 5. Who is responsible and how are Calibration, Maintenance, and Training performed and achieved?
- 6. How will monitoring, verification, and error reporting be handled?
- 7. What is the methodology used to confirm that hydraulic modeling actually represents the hydraulic profile at the LEFM installation site?
m 8. Is coherent noise constant and is that why the measurement of signal strength is an adequate I'V ) indicator for coherent noise?
l
- 9. Clarify that the 0.5% used in the Topical Report is 95% confidence level (26).
- 10. How does the LEFM/ uncertainty compare to the venturi uncertainty at Comanche Peak, in measuring reactor thermal power?
l
- 11. Confirm equations in A-19 of Topical Report for venturi. There appears to be an extra term.
1
- 12. Does cross flow = transverse velocity?
- 13. Clarify the usage of 26 and 95% confidence in the Topical Report.
! 14. Provide the references sited in the temperature correlation uncertainty and an explanation of
! the field data provided in this analysis.
- 15. Explain "non-fluid time delay".
- 16. What is the transducer firing sequence?
- 17. Reference page D-13 of the Topical Report. Is the spool piece alignment uncertainty 0.1% or
(~]
(/ nil?
O N
- 18. Reference page D-14 of the Topical Report. Explain the on-line measurement of the non-fluid ;
f),
Q.
time delay.
- 19. Reference page E-14. Explain how profile factor uncertainty can be bounded for a spool piece that has not been calibrated at a hydraulic lab. I
- 20. Reference Table E-1 of the Topical Report. Explain how reference to ISA RP67.04 applies.
- 21. Reference page F-6 of the Topical Report. Clarify the spool piece tolerance limits, e.g.16,26, l 95% confidence interval.
- 22. What fluid velocities can be achieved during laboratory testing? Explain how extrapolation for Reynolds Number is handled and how its uncertainty is bounded and confirmed in the plant.
- 23. How are swirl and cross flow handled with the LEFM/?
- 24. Provide additional information to support the claim in the Topical Report analysis that many LER overpower events would have been prevented with the LEFM/.
- 25. Are the LEFM/ failure modes different than a venturi? If so, explain. Could any LEFM/
failure modes cause an overpower event?
l
- 26. What is the LEFM/ averaging period and how is it selected? .
RJ
- 27. Clarify where observational uncertainty referenced on page 5-6 of the Topical Report is included in the overall uncertainty. Explain the sources of observational uncertainty and appropriate averaging period. Explain how the appropriate averaging period is determined at commissioning as noted in the Topical Report.
- 28. Provide more data on the historical performance of the LEFM. (CPSES use and experience) l l 29. How is the LEFM used currently to provide correction factors to the venturis? Is the correction determined on the basis of the absolute accuracy or the repeatability of the LEFM7
- 30. What action is taken when the LEFM fails?
I At the meeting the proprietary and non-proprietary responses to 30 questions were discussed. The staff has reviewed the responses presented at the meeting. The following list of additional questions refers to the 30 original questions discussed at the public meeting on September 29,1998.
- 1. Submit response as is.
(] 2. Add to response what methodology will be used by licensees in determination of LEFM to
( ,/ venturi uncertainty improvement.
t.
- 3. Submit response as is.
(V)
- 4. Add a discussion to LER 91-010-00 Ginna LEFM (Ascension Number 9202080130).
- 5. Submit response as is.
- 6. Provide clarification (list) of Quality Control standards used by Caldon in the design and manufacturing of the LEFM. Provide clarification (list) as to the standards followed under Caldon's verification and validation program.
.7. Add a discussion on the practices used by Caldon or required by licensees to ensure that as-built plant configurations are modeled correctly. See page 4 of 8 LER 94-001-01.
- 8. Submit response as is.
- 9. Submit response as is.
- 10. Submit response as is.
- 11. Submit response as is.
7, 12. Submit response as is.
- 13. Submit response as is.
- 14. Submit response as is.
- 15. Submit response as is.
- 16. Submit response as is.
- 17. Submit response as is.
- 18. Add long path and short path definition.
1 1
- 19. Add a discussion on spool piece uncertainties (calibrated, non-calibrated). Explain how the single loop uncertainty in the topical report is different from the CPSES case. What uncertainty assumptions have changed at CPSES?
j 20. Submit response as is.
- 21. Clarify the use of" tolerance limits"(tolerance interval?). It also appears the number of spool O
v pieces tested is discounted in the confidence interval development.
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- 22. If there are flow components that cannot be seen by the LEFM 4 path anangement add a
[]
V discussion on those type of flow components.
- 23. Submit response as is.
- 24. Submit response as is.
- 25. Submit response as is.
- 26. Submit rerponse as is. ,
1
- 27. Submit response as is.
- 28. Submit response as is. Provide clarification of"EPRI standards".
- 29. Submit response as is.
l
- 30. Submit response as is. ;
Additional clarifications as discussed during the September 29,1998, meeting will also need to be addressed and can be incorporated into the above responses as appropriate.
1
. Subsequent to the September 29,1998, meeting the Nuclear Regulatory Commission held a follow- l
[s) up phone call on November 24,1998, to discuss five additional questions that are included below.
The question munbering continues sequentially after the initial 30 questions.
- 31. Explain how figure 5-2 in the topical report was made. Specifically address how the curves were fitted to the information presented in Table 5-1.
- 32. Regarding the answer to Question 10 in the handout material from the most recent. meeting.
Were the uncertainty values for both the venturi and LEFM arrived at using the same methodology? What methodology was used? Give a detailed description of any differences !
I in the combination of uncertainties as presented in the topical report.
- 33. Explain in specific terms why the venturi uncertainty at Comanche Peak is so much lower than that discussed in the topical report (i.e., what uncertainty factors are different and why)?
- 34. Provide a figure analogous to figure 5-2 in the topical using the Comanche Peak site-specific uncertainty values for the venturi and LEFM instruments.
l
! 35. The Caldon Topical report and the answer to Question 25 explain that a benefit of the LEFM is that it is a self-contained " integrated" system. Beyond on-line diagnostics capability, discuss in the application of LEFM at Comanche Peak, how common-mode failures are avoided such
[3 that the uncertainty values assumed for the LEFM remain valid during plant operation. Was V any t)pe of failure modes and effects analysis conducted during system design?
I i
Responses and Further Clari'ications to NRC Questions from September 29,1998 Meeting l Question 1:
Describe Caldon's understanding of the background for 1.02 being ascribed just for instrument uncertainty in power determination.
- Answer
- '
Caldon proposes to increase current licensed power by 1% for plants using Appendix K
, evaluation models without any requirement to reanalyze ECCS performance if the plants l utilize a new technology for determining thermal power. The new technology provides on- I line verification ofinstrument accuracy and is capable of accuracies sufficient to ensure that I 1
there is a higher level of certainty that 102% of the current licensed power will not be l 4 exceeded than is currently being provided, and, hence, a higher level of certainty that the criteria of 10 CFR 50.46 (b) will not be exceeded. l
) As set forth in the Opinion of the Commission in the ECCS rulemaking proceeding, RM '
1, December 28,1973, Section 1.A. of Part 50, Appendix K, specifies the following for the initial conditions to be used in Appendix K evaluation models:
i 4 4
j For the heat sources...it shall be assumed that the reactor has been operating j continuously at a power level at least 1.02 times the licensed power level (to l
- allow for such uncertainties as instrumentation error), with the maximum peaking factor allowed by the technical specifications. A range of power distribution n shapes and peaking factors representing power distributions that may occur over I
,V the core lifetime shall be studied and the one selected should be that which results !
in the most severe calculated consequences for the spectrum of postulated breaks and single failures analyzed.
4 I The question has been raised as to what the phrase "such uncertainties as" implies and j whether operating at a power level 1% higher than the current licensed power could have any i effect on the continued validity of the current Appendix K analyses of ECCS performance. A i review of the regulatory history, including the interim acceptance criteria, the record of the ECCS rulemaking proceeding, implementation of Appendix K, and operating experience, has j tumed up nothing that would suggest that anything other than the need to account for the
! uncertainty of determining the thermal power at which the reactor is operating led to the adoption of 1.02 times the maximum licensed power for an initial condition for Appendix K ECCS evaluations.
The NRC staff, in its concluding statement, had recommended essentially the same initial conditions as were adopted by the Commission. However, the staff had recommended "that the reactor shall be asstuned to have been operating continuously at a power level no lower than 1.02 times maximum licensed power level (to allow for instrument error),..."
Concluding Statement of Position of the Regulatory Staff, RM-50-1, at 40,109. Regulatory Guide 1.49, Rev.1, issued in December 1973, concurrent with the issue of the Commission's opinion in RM-50-1, recommended the use of an assumed power level 1.02 times the
. proposed licensed power for analyses and evaluations of all normal, transient and accident i
v i
l Responses and Funher Clarifications to NRC Questions from September 29,1998 Meeting conditions necessary to evaluate the adequacy of the facility. The staff explained the purpose i f)
LJ of using 1.02 times the proposed licensed power as follows: !
l
... analyses in support of the proposed licensed power are made for a slightly higher l l
power to allow for possible instrument errots in determining the power level. The regulatory staff has concluded that a margin of 2% is adequate for this purpose.
Nowhere in the Commission's opinion is any reason given for the addition of the words "such uncertainties as."
The record shows that the initial conditions of Appendix K had their inception in the ECCS evaluation models approved with the issuance of the interim acceptance criteria. 36 Fed.
Reg.12247, June 1971. See for example WCAP-7422L, Westinghouse PWR Core Behavior Following a Loss-of-Coolant Accident. Id at Appendix A, Part 3. Here,1.02 times the licensed power was used to account for uncertainties in determining the operating power level and the worst possible power distributions and maximum peaking factors were detennined. The maximum peaking factors for which ECCS performance were found to be acceptable were placed in technical specifications for the plants.
The manner in which the initial conditions have been applied since the promulgation of Appendix K is also instructive. Initially, when Appendix K was issued, reactors then operating under the interim acceptance criteria were required to perfom. ECCS evaluations using approved Appendix K evaluation models. Since the worst possible power distributions o and maximum peaking factors allowed by the then current technical specifications were used, kj unless, of course, the Appendix K evaluations supported different values. (As specified in 10 CFR 50.36, the technical specifications must be derived from the analyses and evaluations in the safety analyses reports and amendments thereto. Hence, the maximum peaking factors allowed by plant technical specifications must be consistent with the maximum peaking factors used in the ECCS evaluations which demonstrate that the ECCS performance satisfies the criteria of 10 CFR 50.46(b).
In general, in applying initial conditions for the interim acceptance criteria and those required by Appendix K,Section I.A., the following were incorporated in approved ECCS evaluation models:
- 1. Reactor power assumed to have been continuously at 1.02 times the licensed power (or proposed licensed power in case of amendments) to account for uncertainties in determining thermal power.
- 2. A cosine curve representing the power distribution shape resulting in the worst consequences (normally the highest calculated peak clad temperatures). The cosine curve is worse than any other power shape occurring at any time in core l life. This shape can only occur during a return to power and for a short time l thereafter and is not possible in continuous power operation. Hence it is an extremely conservative assumption; and 2
i l
Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting
- 3. The maximum peaking factor in the technical specifications (or proposed l to be placed in the technical specifications);
These three assumptions have then been used in the Appendix K evaluation models as inputs l to calculate the initial stored energy in the fuel, fission heat, and decay heat from actinides and fission products. None of these input assumptions are affected by increasing the operating power provided that the operating power does not exceed the 1.02 times maximum licensed power assumed in the evaluation of the ECCS performance showing that the criteria of 10 CFR 50.46(b) will not be exceeded. This is consistent with the objective stated in the opinion of the Commission in RM-50-46 dealing with conservatism:
(1) Stored Heat. The assumption of 102% of maximum power, highest l allowed peaking factor, and the highest estimated thermal resistance between the UO2 and the cladding [ calculated using the above input assumptions]
provides a calculated stored heat that is possible but unlikely to occur at the l time of the hypothetical accident... Opinion of the Commission, RM-50-1, December 28,1973 at 27, A-4.
Thus, it appears that the approval of the Caldon proposal resides solely in demonstrating that L
there is a sufficiently high probability that the power level assumed for evaluation of ECCS performance in existing Appendix K evaluations will not be exceeded in operation at a 1%
increase in licensed power level with the proposed improved technology for determining plant operating power.
' A review of the Standard Review Plan (SRP) was also conducted to identify references to application of the 2% margin to initial conditions for accidents. The results, summarized in l Attachment 1, indicate that the 2% margin for initial conditions is required for analysis of 12 l accidents in SRP Chapter 15. Of these 12 accidents, the license is permitted to use less than 2% margin in 9 cases provided the lower margin can be justified by the applicant.
l i
Attachments:
l 1. Summary Table of Review of Chapter 15 of Standard Review Plan.
- 2. Three Legal Research Memos Additional Clarification Requested:
During the meeting on September 29,1998, the NRC Staff requested that they be informed if any notes from the ACRS meeting (s) on the subject of the history of the 2% margin were found, and of their contents.
Answer: The legal tesearch on this topic is attached to this answer.
- o 3
l
Responses to NRC Questions: September 29,1998 1
Attachment 1 to Question 1 O, w i
Sectise of Chapter 15 Reference to 102% inittel Permission to use power level condition below 102% Ifjustifled i 15.1 1 through 4: Decrease in Yes Yes Feed temp etc.
15.1.5 Seesm sys piping failures No .
in and out of containment I 15.1.5 A Rad Conseousaces No I
- 15.2.7 Loss of Normal Feed Nw Yes Yes l l 15.2.8 Feed System Pipe Breaks No
-PWR 15.3.1-2 Loss of forced reactor Yes Yes coolant Nw 15.3.34 P.eector coolant pump Yes Yes
. motor seimre ;
I 15.4.1 Uncontrolled Control rod No
- wahar.wai- sabernicauiow
- 15.4.2 Uncontrolled Withdrawal No i at Power i v 15.4.3 Control Rod Malfbaccan Yes Yes 15.4.4 5 Startup ofinactive loop Yes No
, v and flow controller malfunction-BWR l 15.4.6 CVCS reduces baron Yes No concentration PWR 15.4.7 Inadvertent Loading of No
- fbel assenhly i
15.4.8 Spectrum of rod ejection No
- accidents- PWR j 15.4.8 A Rad Consequences of No Ejection
- ' I5.4.9'# -.sii of rod drop No accidents-BWR '
15.4.9 A Rad -- -_--= No 15.5.l 2 Inadvertent Opennon of Yes Yes ECCS that increases inventory 15.6.1 Inadvertent opening of Yes Yes PWR or BWR pressure relief valve 15.6.2 Rad consequences of the No failure of smalllines carryins v
O
- Responses to NRC Questions
- September 29.1998 2
Attachment 1 to Question 1 r
O)
- Section of Chapter 15 Reference to 192% lattial Permission to see power level cWition below 192% if justified pnmary coolant outside contaanment l
15.63 Rad m- of No 4
steem generator tube rupture - 1 PWR '
15.6.4 Rad W.s of No Main Stearn Line Failure Outside 3 containment- BWR 15.6.5 LOCA resulting from Yes Yes
, spectrum of pipe breaks within
, RC pressure boundary 15.6.5 Apps A, B, C, D: Various No j rad =- - c- = of LOCA i 15.7J Rad releases due to liquid No contamina tank failures 15.7.4 Rad ~=M- of fbel No handlina accidents 15.7.5 Spent fbel cask drop No accident.
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- 1
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3O jQ Memo to: Emest M. Hauser Caldon, Inc.
- From
- Denwood Ross Censultant to Caldon
!. l j
Subject:
- i. Review of instrument Uncertainty Factor in Context cf Appendix K to 4
Part 50 of10CFR Statement of the Prem For some time there has t:een a requirement, in Appendix K to part 50,and elsewhers, to analyze certain transients and accidents at 1.02 times the licensed power level. There is a reasonable nexus of the 2% overpower assumption to ;
uncertainties in the measurement of reactor power level !
One possibility for increasing the power level (thermal and electrical) of the reactor, without the need for redoing the thermal-hydraulic (and in some cases, radiological consequence analyses) is to reduce the uncertainty in the 2%
value. For example, if modern developments allowed the utlization of 1%
uncertainty, in equivalence to the 2% formerly used, then the licensed power l level could be raised 1%, and the transient and accident analyses would still be bounding.
% Inasmuch as the reguity ons prescribe 2% (in Appendix K) there sti!!
remains the question of literni compliance, which must be dealt with in terms of an exemption and/or, eventually, a change in the rule itself, i
The stated problem is to provide insight as to the attribution, in regulatory j guidance, of the 2% overpower requirement. As justified in this memo, there is ample justification ibr the assertion that the 2% factorin Append (x K was l intended to provide margin in terms of power level measurement, and nothing else. Further, there is good reason to believe that an exemption to Appendix K (until and unless the rule la changed) should be granted, in that there is no genuine safety issue that would mitigate against it. .t Annandix K History i
The US Atomic Energy Commission issued an opinion on December 28,1973 !
that provided the Commission's rationale ibr the modification to 10CFR50A6, and Appendix K to part 50, with respect to the Loss of Coolant Accident.
l This 140-page opinion contained the Commission rationale for adopting the required and acceptable flectures for the evaluation of the postula'ad breaks in i the piping of nucieer power remotors. {
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__ _ . _ - . _ _ , - _ _ . ~ ~ _ _ . _ _ . _ . _ . _ _ . _ ._ ___ _ _ _
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. Among other things, the opinicn ref'ected en the margin of conservatism tha was considered to be in the features of 50.46 and Appendix K. Some relevant quotes from that opinion are;
- g. a. *lt is probable that, with a better data base, some relaxation een be made in some of the required features of the evaluation models.' '
l i b, 'For the heat sources listed in paragraphs 1 to 4 colow it shall be i l assumed that the reactor has been operating continuously at a power j level of at least 1.02 times the licensed power level (to allow for such
, uncertainties as instrumentation error), with the maximum peaking l factor allowed by the technical specification.
c.
- "There is some margin provided, however, in the prescription
- requiring that the reactor shall have been considered to have operated continuously at 1.02 times rated power, with the maximum allowed 4
peaking factor, for an infinite period of time.**
l
, In fact, the safety research program' that took place over the fifteen years
! following the promulgation of Appendix K verified that there were numerous I conservatisms in the required features of evaluation modela. For example:
- a. the decay heat standard was shown to be about 20% too high;
- b. the conservative assumptions on water delivery to the lower plenum of PWRs*
- c. assumptions on steam availability for metal water reacNon of the fuel cladding at elevated temperature.
The general position of the AEC regulatory staff throughout the ECCS bearing was that the models should be 'overall suitably conservative'.
Conservatisms such as those listed above, and others, were felt to be true at the time. However, the data were lacking to prove it.
While the Commission Opinion is a little ambiguous with respect to attribution of the 2% allowance as strictly calorimetric accuracy only (viz. the phraWsuch as'), it is my recollection that the regulatory staff had that in mind.
We '.ad further allocated uncertair ty in the decay heat by using a se. carate 20%
value there, and had prescribed uncertainty in the peaking factor by the requirement that the maximum values be used (even though it was dMeuit, if not impossible, to schove thew osaking factors in operation), inasmuch as
' See pese 30 of15e opinion. De Comassion went on to say that any A ture relaxation in some ofth required thatures of the evaluation models sh:iuld retain a energin of safety above and beyes i allowances fbr statissaal artor.
8 See Section !!!.A in tbs Opinica, titlet Basaltaund A~ ==Ala Femmes ofthe E==L% We Paragraphs 1 4 dealt with initial stored energyin the fuel, fission heat; decay oractinides, and fission foductdecay See the Discussion fbilowing Section M.A in the Opinion The Commission went on to esimate that the exact amount of marsin is uncertain, and it will very with time, but it is probabiy in the range of 5 to 15%
- See the Opinion, Section C.I.c, regarding the end ofblowdown. The requirement is subtract all orthe -
coolant injected during blowdown. ror the rent ofrha ulalation. L.re .i. teos. wnducted andmyuem to Appendix K have shed further light on the question ofinteraction of the ECCS and the blowdown phenomena, and have shown that this was a significant overconservatisnt 2
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separete margins of safety were allocated for these heat sources, it would not make sense to ascribe the 2% to any thing other than calorimetnc, especially in context of other guidance contemporaneous with Appendix K (see below).
Other Reculatorv Guidance Regulatory Guide 1.49, Revision 1 (December 1973).
This guide is entitled Power Levels of Nuclear Power Plants. The main purpose of this guide was to put a cap on thermal power levels of plants, in order to gain sufficient experience with design, construction, and operation of large plants. in terms of instrument errors in determining power level, the guide states that: ,
l The Regu! story Staff has determined that a margin of two percent of the lleensed power level is adequate for this purpose.' :
The guide goes on to specifically state that the acceptability of the site, in accordance with Part 100. should be demonstrated for a power level of 1.02 times the Ilcansed level. Here, the reader should refer to the standanf footnote in regulatory guides to the effect that:
'Methocs and solutions different from those set out in the guides will be acceptable if they provide a basis for the findings requisite to the issuance or continuation of a permit or license by the Commission.'
i Regulatory Guide 1,157, May 198g.s This guide is entited Beat.Estimata Cahlations of Emeroencv Core CMine Svatam Performance. It relates to an amendment to 50.46 and Appendix K,
[mh wherein licensees could use a realistic evaluation model. An interesting quote of
(/ this guide is:
"The Appendix K requirements tended to divert both NRC and industry risources from matters relevant to reactor safety to analyses known to be nonphysical."
The significance of this reference is that the NRC is open to arguments for using more realistic information when it is available, and justifiable. For example, this guide cites as a reference (number 10 in the gulde) the 1979 version of the ANS decay heat standard, while Appendix K incorporates the 1971 version. The 1971 version, which was suspected by the regulatory staff to be overty conservative, is about 20% higher than the 1979 version, over the range of interest. This would support the thesis that more realistic features (such as 1%
osiorimetne error vs. 2%) can be used if justified.
Informal Guidance Redino Pc=,- Level Uncertaintv The regulatory staff het had, since 1980, written (albeit informal) the reactor resident inspectors on the subject of ficensed power level.pidance to 8
It la undmtood that. Aw the enesi part. runnet'w
. evolustion modele are not going to be usea la connection with the reducdon in innrutnant uncertainty u justifled by Caldon. However, ela resulacry adde illuserstes areas where conservatism could be relaxed.
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This memo is in context of the uncertainty in measurement of reactor power, although this is not specifically stated in the memo. Numerous discussions took place prior to the issuance of the memo. There were some that argued that power level should be controlled at a nominai 98% power, so that the inherent uncertainties wculd then be compensated. However, the prevailing viewpoint was that random variations could be tolerated, within plus/minus 2%, with de minimis affect on safety. This nearly-20-year old memo states that the policy of allowing the eight-hour everage power to be at 100%, with random fluctuations around that band not to exceed 102% would be used until superseded by more formal guidance. Such operation would be considered within the licensing basis.
In fact, such guidance has not emerged, and this 1980 memo is still being used. On the average, the NRC receives one or two reports per year that a plant has operated outside this guidance.
Current Licensino_Ragig An example of the current licensing basis as documented in an Updated Final Safety Analysis Report (UFSAR) can be seen in the Comanche Peak UFSAR. The accident analysis chapter (Chapter 15) has a general statement in the opening section that when initial power operating conditions are assumed in accident conditions (such as LOCA), and then an allowance for errors in steady power determination is assumed. Further, the steady state enorin core power determination is stated to be plus/minus 2%, for colorimetne error.'
inasmuch as the NRC has reviewed this document and accepted it as the current licensing basis, it seems clear that there is an inescapable assocation of the 2% overpower requirement with instrument error.
k Literal Comnilance There is the queston of literal compliance. If there is a requirement embodied in the rule for a 2% overpower assumption (such aa In Appencix K) then such a requirement applies equally to the staffin its work. Tnus, the NRC staff would not have the liberty to reinterpret a rule, without going through the formality of rulemeldng.
Proeumebly there would be a fsycrable reception to an exempdon, until or unless there is a rule change.
The next step would be to work on a technical basis for an ex,emption. It is well known that considerable margin exists between the overty conservative Appendix K requirements, and roeirty. Even at the time of the promulgation of Appendix K there were calculations showing temperature margins of substantial proportions (best estimate calculations were more than 500 dog F below Appendix K).
- Memo, E1. Jordan (Assistant Duector for Technical Programs of the Of5ce for Ir.spection and W..c.O to Regional Manasers; on the subject: Dh6 of*Lloonsed Power Level'; Aug 22,
)940.
See page 15.01 f, item 1 at the top of the page, of the Comanche Peak LTSAR, as updeed'7 Apnl IS, 1994.
A v
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1500 i t
Appendix K
'1 00
- oca A
Realisuc 1000 l
l D 1500 Realistic O*Mation N C J soo l I
f and Decay Power !
s i
8 1000 M
f g
s 400 l
g 500 1
t e . .
9 0 0 25 50 75 100 125 150 173 200 Tae AAmr ansk 4)
Effect e(selsewd conservatisms os peak cladding tempersture I I
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h ECKERT SEAMANS CHERIN & l\ELLOTT, LLC
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MEMORANDUM TO: Mr. Calvin R. Hastings Mr. Ernest M. Hauser FROM: Barton Z. Cowan, Esq.
Robert A. Wiesemann, Esq.
DATE: October 14, 1998; Revised December 9,1998 RE: Origin of the 10 CFR 50, Appendix K, Power Factor Appendix K to 10 CFR Part 50 -- ECCS Evaluation Models,Section I.A., specifies the sources of heat to be used in Appendix K ECCS evaluation models (Appendix K was adopted on January 4,1974). Among other things,Section I. A. requires the assumption that the reactor has been operating continuously at a power level at least 1.02 times the licensed power level to allow for such uncertainties as instrumentation error. In an attempt to o determine the basis for arriving at the 1.02 power factor, we reviewed the concluding i :
statement of the NRC staff, the opinion of the Commission in the ECCS rulemaking proceeding and the letters issued by the Advisory Committee on Reactor Safeguards (ACRS).
While the use of the 1.02 power factor is acknowledged in the staff concluding statement and the Commission opinion documents, there is no discussion of any underlying basis for it.
We personally participated in all of the ECCS miemaking hearings and, to the best of our knowledge and recollection, the 1.02 power factor was never at issue.
Further research with respect to power limitations turned up a Commission Policy Statement isst'ed on March 5,1973 encouraging, supporting and giving priority to greater stan. ardization of nuclear power plants. In that statement, the Commission announced that the sc of all new plants accepted for licensing review would be limited to 3,800 megawatts thermal. A review of regulatory guides indicated that Regulatory Guide 1.49 ("RG 1.49")
had been issued in May 1973 to provide guidance with respect to the limitation of power level. RG 1.49, Rev.1, issued in December 1973, in Section C, specifically states that
" analyses and evaluation in support of the license application should be made at an assumed core power level equal to the proposed licensed power level (with a maximum acceptable value of 1.02 times 3800, or 3,876 megawatts thermal) for (a) normal operating conditions, (b) transient conditions anticipated during the life of the facility such as load changes, control rod malfuntions and improper operations, loss of forced coolant flow, loss of load or turbine trip, loss of normal a-c power, primary system depressurization, etc., and (c) accident conditions necessary to evaluate the adequacy of structures, systems, and components provided for the prevention of accidents and the mitigation of the consequences of accidents."
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(1 There is no reference to any source for the 1.02 power factor in RG 1.49, Rev.1. We reviewed the NRC Public Document Room file for the development of RG 1.49 and found i ,f3 no reference to any source of the 1.02 power factor nor any indication of any review and y/ approval process.
We also reviewed the Interim Acceptance Criteria for Emergency Core Cooling Systems for Light-Water Power Reactors (" Interim Acceptance Criteria") issued on June 29,1971. We found no reference to the 1.02 power factor anywhere in the Interim Acceptance Criteria.
However, Appendix A of those criteria approved specific ECCS evaluation models. The descriptions of the approved ECCS evaluation models also did not contain any reference to any power factor. The description for each approved ECCS evaluation model referred to reports in which the analytical techniques to be used were described. Thus, with respect to the Westinghouse model, the Interim Acceptance Criteria stated:
The analytical techniques to be used are described in the topical report,
" Westinghouse PWR Core Behavior Following a Loss-of-Coolant Accident" WCAP-7422-L January 1970 (Proprietary), and a supplementary proprietary Westinghouse report, " Emergency Core Cooling Performance," received June 1,1971, and in an appropriate nonproprietary report to be furnished by Westinghouse, with the following exceptions: [ exceptions not relevant]"
We reviewed the Westinghouse report (WCAP-7422-L) and found the following explicit discussion of the 1.02 power factor:
. The core thermal analysis utilizing the design power distribution is made for
( initial operating conditions of 102 % of 2758 MWt, an inlet coolant temperature of D) 547' F, and system pressere of 2220 psia to account for possible errors in steam cycle calorimetric measurements and other instrumentation. . . WCAP-7422-L, Page 5-2.
The design core inlet temperature and system pressure are 540 F and 2200 psia, respectively. The error allowance for each is about 1% and is incorporated in WCAP-7422-L independent of the 1.02 power factor, leaving that factor to account for the total uncertainty in measuring core thermal power. Calorimetric measurements are used periodically to calibrate the ion chamber current, measurements of which provide the indication of core thermal power to the operator. For example, see Prairie Island Nuclear l Station, Unit 1, Docket 50-282, FSAR, Amendment 19, Page 14-5, dated 7/17/72. Thus, the 1.02 factor accounts for the calorimetric instrumentation uncertainties and potential ion chamber drift between the periodic calibrations.
The 1.02 power factor referred to in WCAP-7422-L actually was developed and used in this manner in the licensing of nuclear power plants prior to the issuance of the Interim Acceptance Criteria. It was carried forward as discussed above in the Interim Acceptance Criteria and ultimately included in the ECCS Acceptance Criteria in 10 CFR Part 50,
, Appendix K.
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1 ECKERT SEAMANS CHERIN & MELLO'IT, LLC MEMORANDUM TO4 Mr. Calvin R. Hashs Mr. Penset M. Hanser FROM: Burton Z. Cowan, Esq. ,
Robert A. WW===. Esq.
DATE: Ocsober 26,1998 RE: Review of ACRS IAtters and T.-We ihr Discussion of the 10 CPR Put 50, Appendix K.1.02 Power Psctor i
O rac swi> ^c== -i ad ih. =ces ' - * ^ - +z-- cra==i aAc> in iis 140t - tini.
the BCCS Faal Aeoepanee Crheria (FAC) in its 161st meet ng i and ECCS Evaluatlan Models sdenhed by the vendors pursuant to ths FAC in its 175th meeting. We reviewed j each of the ACRS leenre to the W of the SnenWan reperting en these subjects.
4 Thus was no mention of the 1.02 power footer la any of these leases.
In mMkiaa to these laaert, we reviewed aletter to the Chainnan dated M wf 26, 1968, on the ACRS review of the Raport of the Advisory Tasit Parce On Power Rascior Core
[
U Cooling (ao meeting referenced) and ACR$ sospcases to hhn.wks mibmitted by the Conaalh=d National Intervanors in the ECCS Bniemaldnt Proceeding 004-501) dated
' October 27,1972. We fbund no Ataenenlaa of the 1.01 power factor in any of this ACRS i -+h.
'I We also reviewed a summary of the 140th ACRS meeting (no vertatim u-@ is y
avaBabic), and the La ; 4,ti of the 161st and 175dtInsetings (fbr the 161m meeting, treascripts are aveliabla for only the ihst two days of the sneeting). We fbund no discussion
- of the 1.01 power factor inthe namnary of the 140th ACRS Mr. The LAM of the
! fkst day of the 161st meeting contains discussions of BAW soslysis methods for ECCS l
parthemmm used jbr Rancho Seco pursuant to the IAC. The a-y of tha 175th tooedag j oontains extensive Maanasians of BCC5 evaination models approved pursuant to the FAC.
On page 64 of the transcript of the first day of the 161st M= in goestions
) about the BCC8 analyses fbr Rancho seco, BAW presented a table of design applied i to operating hast rates. The table ielada abt fheters. Nuclear Uncertainty. Hot Cimanal 3
Pactor. Quadrant Tut, Axia1 Power inhaimaca, Ptmer Uh Ai, and Puol Wnanw.
j The Power Uncertaisty flector is shown a be 1.'A On pages d6 to 68, BAW descrthed how 1
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O these design factors were applied. In this desenprion, B&W points out that the 1.02 Power Uncertalmy was appI!ad to the beat rates obtainad after applying the other design factors, thm being applied independently, nis would indicate that the 2.02 power uncertainty was WW to allow for measurement uncertantes since the other factors aircady take into ,
account the other uncertainties.
In opemng the diamacions of the FAC ECCS evabunnn models in the 175th meeting, the l ACRS reviewed the differences between the FAC and the IAC. With respect to sources of heat, the discussions iachtdad differences with respect to flux shapes and decay heat.
Although the FAC inchdM a 1.02 power hetor and the IAC did not (a power factor was whvimi by each vendor in its evaluation model approved pursuant to the IAC), there was to discussion of this difTerence. W only reference to the 1.01 power factor in Ibe 175th meeting came up on page 153 of the transcript during ACRS quecioning GE about its evaluation model. GE was perfonning it ECCS evalnation at 100% nnmimi power and was not applying the 1.02 power factor in the way Part 50, Appendix K, required because of a misinterpresation of the mIc. W ACRS, an pages 158 and 159, obtained a commitment from GE to change hs analysis methods and perfonn the analyses from an inihn1 power level of 1.02 times leaamd power.
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ECKERT SEAMANS CHERIN & MELLOTT, LLC O
V MEMORANDUM i
TO: Mr. Calvin R. Hastings Mr. Ernest M. Hauser FROM: Barton Z. Cowan, Esq. l Robert A. Wiesemann, Esq.
DATE: December 9,1998 RE: Review of D. Ross Memorandum Regarding the 1.02 l Uncertainty Factor in 10 CFR Part 50, Appendix K 1
l On October 14, 1998, we submitted to you a memorandum entitled " Origin of the 10 CFR 50, Appendix K, Power Factor." In that memorandum we concluded that the 1.02 power i factor utilized in Appendix K was included solely to account for uncertainties in measuring !
core thermal power during operation. Enclosed with this memorandum is a revision of our i October 14,1998 memorandum in which we have further clarified the bases for our opinion.
C We previously have discussed these clarifications with you, and advised that clarifications do k not alter the conclusions reached in our October 14,1998 memorandum. l We also have reviewed a memorandum of Mr. D. Ross entitled " Review of Instmment l Uncertainty Factor in the Context of Appendix K to Part 50 of 10 CFR," dated October 27, j 1998. In his memorandum, Mr. Ross independently reached the same conclusion as we had l reached with respect to the reason for the inclusion in Appendix K of the 1.02 power factor.
In reaching his conclusion, Mr. Ross relied upon a number of documents which we also relied upon. However, his analysis also relied upon certain additional documents which we did not possess. Further, our analysis relied upon certain additional documents which Mr.
Ross did n'ot mention in his memorandum. Taken together, our mernorandum and Mr. Ross' memorandum clearly show that the intent behind the 1.02 power factor was solely to account for uncertainties in the measurement of core thermal power during operation.
BZC/jmg l
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Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting -
Question 2:
O On page 5 2 of the topical Report, explain the justification for the use of PTC-6.
l - Answer:
The conWxt of the reference to PTC-6 is repeated here from page 5-2:
l l
"Immediately after it is calibrated, a flow nozzle is capable of providing measurement accuracies in the 0.5% range, providing the differential l pressure and fluid temperature measurements are made with laboratory grade, calibrated instruments (see for example the discussion of turbine heat rate testing in ASME-PTC-6, Reference 9)."
PTC-6 is referred to for purposes ofillustration only and does not apply to the use of the LEFM/ for thermal power measurement.
l Attachments: I l
None. ,
I Additional Clarification Requested:
i
,o . Add to response what methodology will be used by licensees in determination of )
LEFM to venturi uncertainty improvement.
Answer:
The licensee will use methodology for the LEFM/ uncertainty accounting that is consistent with the methodology in use for the existing thermal power uncertainty at their ,
l facility. The LEFM/ thermal power uncertainty calculated by the licensee will be shown I to be bounded by the uncertainty of i 0.6% presented in the Topical Report, and the site-l specific analysis will be available at the licensee's site for review by the NRC upon l request.
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Respcnses and Further Clarifications to NRC Questions from September 29,1998 Meetii.g j 73 Question 3:
Describe how the LEFM/ is used in calorimetric power determinations.
Answer:
The proposed use of the LEFM/ is for direct measurement of feedwater mass flow and temperature, and indirect measurement of feedwater enthalpy, for the thermal power detennination. This determination would be used directly to calibrate the nuclear instruments in lieu of the existing instrumentation. At the discretion of the licensee, the LEFM/ may also be used for calorimetric calculation of reactor coolant flow, and for setting non-safety-related setpoints for which thermal power is an input. The increased accuracy as compared to the existing instrumentation would be beneficial in these applications.
At Comanche Peak, the LEFM is currently used for the secondary calorimetric calculation only. The secondmy calorimetric is used as input for the daily calibration of NIS and the cross-correlation N16 system.
In some plants, feedwater flow and/or temperature instruments are used as direct inputs to the reactor protection sy stem or another automatic safety function. In these cases, those instruments are classified as safety-related, and would continue to be used for these functions. The LEFM/ is not being proposed for these functions. Its use would be
- limited to power determination and the non-safety-related uses of calorimetric power l'%>j discussed above.
Attachments:
None.
Additional Clarification Requested:
None.
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Responses and Further Clarifications to NRC Questions frorn September 29,1998 Meeting
,s. Question 4:
V)
I Address LER 94-001-01 which applied to older LEFM models and how the event would be avoided in the LEFM/.
Answer:
LER 94-001-01 addresses an error in calculated thermal power due to an older Westinghouse Model 601 LEFM in use at Point Beach Unit 2 in March of 1994. This LER was discussed briefly in Section 7.3 of the Topical Report. This discussion from page 7-3 of the Topical is excerpted below:
The second event was a miscalibration ofventurifeedwaterflow measurements using a Westinghouse model ofthe LEFMsystem that had been installed in the early 1980 's. This event resultedin a 1% non-conservativefeedwaterflow indication. but did not cause overpower operation since the plant was operating at 98 % powerfor other reasons at the time. This event was caused by signal strength degradation which was not corrected by normal maintenance, and was not reported by the older LEFM model in use. The event would have been prevented by use of the LEFM/ system, because the on-line verificationfeatures ofthe LEFM/would not permit operation outside the commissioned set-up as did the older LEFMsystem in use.
g V Specifically, the LEFM/ measures and verifies [ ], which was not possible with the LEFM Model 601. Though the Topical Report does not directly reference LER l
94-001-01, this is the case being discussed. Point Beach subsequently installed a Caldon upgrade to their system in response to this event.
There are two other events described in the Topical report in the same section. Both ,
events involved the use of Controlotron externally mounted meters, and both would have l been prevented had the LEFM/ been used. One was a transducer coupling degradation problem at Kewaunee, and the other was an undetected flow profile error encountered at North Anna. Bases for prevention of both using the LEFM/ are provided in the Topical Report, Section 7.3, attached.
Caldon has also recently searched LER's submitted since March 1997 to discover any additional events concerning the use of ultrasonic flow meters which post-dated the Topical. One was found. LER 97-005-01 was filed by CP&L for Brunswick Unit 1 in August of 1997. CP&L conducted a flow measurement test using an externally mounted ultrasonic flow meter. This device was not a Caldon LEFM. The test results indicated that the Unit i feed system flow indication was potentially non-conservative. A non-conservatism of 1.3% was confirmed by review of original venturi calibration data from i weigh tank tests performed during plant construction. The non-conservatism was found to be due to a re-calibration of the venturis to chemical tracer test data in 1994. CP&L g
U 1
1 Respenses and Further Clarifications to NRC Questions from September 29,1998 Meeting concluded that neither the ultrasonic meter test results nor the tracer test results were as accurate as the original venturi weigh tank test results, and the venturis were returned to s
their original calibrations. This LER would also have been prevented by use of the LEFM/ since results of both the tracer and ultrasonic tests could have been compared to a measurement which could be verified on-line. Test results would have been questioned
- before being used, on the basis of this standard.
References:
- 1. LER 94-001-01, " Potential Feedwater Flow Inaccuracies", Point Beach Nuclear Plant, Unit 2
- 2. LER 97-005-01, including Supplement 1, "Feedwater Flow Discrepancy - Voluntary Report" Brunswick Steam Electric Plant, Unit 1
- 3. NRC letter dated February 27,1997, with enclosed Inspection Report 99901311/97-01.
- 4. Section 7.3 of the Topical Report.
Attachments:
None.
Additional Clarification Requested:
Add a discussion on LER 91-010-00 Ginna LEFM (Ascension Number 9202%0130).
Answer:
The Ginna LER did not retum in the list from our original searches of the PDR database.
This was apparently because of the combination of key words used. The failure reported by Ginna was a lock-up of the HP-85B computer on an older Westinghouse Model 824 LEFM which caused the output to freeze at a constant value not representative of the actual flow rate. [ ]
We have performed a new search of the PDR database for events related to ultrasonic
~
flow meters and have found three additional LER's, all related to an ultrasonic flow meter application (vendor not specified; not a Caldon meter) at Crystal River 3 in the early 1980's. These LER's are reported on a form which does not include an LER or accession number. The event dates are March 21,1982, December 20,1982, and July 21,1983.
Technical specification violations are described due to inoperability of the flow meter due to various failures, including power supply failure, electrical malfunction due to excessive temperature in the emergency feedwater line, and improper application of a low temperature couplant to the outside of the pipe. The ultrasonic flow meter, apparently of an external mount design, was reportedly replaced in 1983 with " conventional instruments" during the following refueling outage. No further reports were found.
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l l Responses and Funher Clarifications to NRC Questions from September 29,1998 Meeting concluded that neither the ultrasonic meter test results nor the tracer test results were as
[ accurate as the original venturi weigh tank test results, and the venturis were retumed to L their original calibrations. This LER would also have been prevented by use of the l LEFM/ since results of both the tracer and ultrasonic tests could have been compared to l a measurement which could be verified on-line. Test results would have been questioned l before being used, on the basis of this standard.
l
References:
- 1. LER 94-001-01," Potential Feedwater Flow Inaccuracies", Point Beach Nuclear Plant, !
Unit 2 l
- 2. LER 97-005-01, including Supplement 1, "Feedwater Flow Discrepancy - Voluntary l Report", Brunswick Steam Electric Plant, Unit 1
- 3. NRC letter dated February 27,1997, with enclosed Inspection Report 99901311/97-
- 01. '
- 4. Section 7.3 of the Topical Report.
Attachments:
l None. i Additional Clarification Requested:
Add a discussion on LER 91-010-00 Ginna LEFM (Ascension Number 9202060130).
D Answer:
The Ginna LER did not return in the list from our original searches of the PDR database.
This was apparently because of the combination of key words used. The failure reported oy Ginna was a lock-up of the HP-85B computer on an older Westinghouse Model 824 LEFM which caused the output to freeze at a constant value not representative of the actual flow rate. [ ]
We have performed a new search of the PDR database for events related to ultrasonic flow meters and have found three additional LER's, all related to an ultrasonic flow meter application (vendor not specified; not a Caldon meter) at Crystal River 3 in the early 1980's. These LER's are reported on a form which does not include an LER or accession number. The event dates are March 21,1982, December 20,1982, and July 21,1983.
Technical specification violations are described due to inoperability of the flow meter due to various failures, including power supply failure, electrical malfunction due to excessive temperature in the emergency feedwater line, and improper application of a low l temperature couplant to the outside of the pipe. The ultrasonic flow meter, apparently of l an extemal mount design, was reportedly replaced in 1983 with " conventional
! instruments" during the following refueling outage. No further reports were found.
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l Responses and Funher Clarificitions to NRC Questions from September 29,1998 Meeting Question 5:
L. /'S Who is responsible and how are Calibration, Maintenance, and Training performed and achieved? -
Answer:
l i
i Calibration and Maintenance i
i Calibration and maintenance is performed by I&C using site procedures. The site l procedures are developed using the CALDON technical manuals. All work is performed l m accordance with site work control procedures, l
l Routine preventive maintenance procedures include physical inspections, power supply )
checks, back-up battery replacements, and internal oscillator frequency verification. l 1
- Ultrasonic signal verification and alignment procedures which involve digital
! oscilliscopes with the LEFM will be replaced by automatic set-up in the LEFM/. Signal verification will still be possible by review of signal quality measurements performed and displayed by the LEFM/.
Training I&C personnel must be qualified per the I&C training program on the LEFM system before work or calibration may be performed. Formal training from Caldon was provided j O' to site personnel. Formal training on the LEFM/ system will be provided by Caldon.
Attachments:
None.
- Additional Clarification Requested
None.
l lO l 1 l
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__ .m.-_._ .. .. _ . _ _ -m-_.-.___ -_.._.___..-m._ _
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Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting Question 6:
How will monitoring, verification, and error reporting be handled?
Answer:
Though this application is not safety-related, the LEFM/ system is designed and l manufactured under Caldon's Quality Control Program , which provides for
- configuration control, deficiency reporting and correction, and maintenance. Specific l examples of quality measures undertaken in the design, fabrication and testing of the LEFM/ system are provided in the Topical Report, Section 6.4 and Table 6.1. Table 6.1 lists the error bounding, validation and verification procedures planned for the LEFM/
system.
At Comanche Peak, the LEFM system is included in the System Health Plan and the
- preventative maintenance program. The system is monitored by the System Engineer for reliability. As a rhnt system, all equipment problems fall under the site work control process. All conditions that are adverse to quality are documented under the ONE/ SMART form program. The software falls under TU Electric's Appendix D QA
, program with a software QA plan in place. The current software was verified and validated and is under Caldon's Verification and Validation Program. Caldon's Verification and Validation Program provides procedures for deficiency reporting for engineering action and notification of holders of V&V software.
The Comanche Peak LEFM/ System will likewise be under Caldon's V&V Program, l and procedures will be maintained for user notification ofimportant deficiencies.
Attachments:
None.
Additional Clarification Requested:
1 I
Provide clarification (list) of Quality Control Standards used by Caldon in the design and manufacturing of the LEFM. Provide clarification (list) as to the standards followed under Caldon's verification and validation program.
i Answer:
l l
L Caldon is an ISO 9001 certified manufacturer and has been audited accordingly. Quality Control standards used by Caldon in the design and manufacturing process of the LEFM/ are listed below:
l O 1 l -
. _ _ ~ . _ . . . . . _ . . . . _ . _ _ . . . _ . _ _ _ - . . . _ - . . . _ _ _ _ _ ._ ._.- .__ ___... _ . .._
l
' Responses and Furth r Clarifications to NRC Questions from September 29,1998 Meeting ANSl/ ISO /ASQC )
Q9001 1994 Certified Manufacturer.
I.* ASME NQA-2A 1990 Quality Assurance Requirement of Computer Software for Nuclear Facility l' Applications, Part 2.7 IEEE 7 4.3.21993 IEEE Standard Criteria for Digital Computers in Safety Systems for Nuclear l
- Power Generating Stations; Annex E ASME B31.11989 ASME Code for Pressure Piping l NEC 1993 Article 240 - Overcurrent Protection l
. Article 250- Grounding i
Article 300 - Wiring Methods l
EIA (RS-232C, RS-422) Interface Between Data Terminal and Communication Equipment Employing I
Serial Binary Data Interchange
' EPRI TR-103291s Handbook for Verification and Validation of Digital Systems, December 1994 (as applied to software)
EPRI TR 10323 Rev.1 Guidelines for Electromagnetic Interference Testing in Power Plants l
l Caldon's Verification and Validation program for the LEFM/ is designed to fulfill the requirements of ANSI /IEEE-ANS Std. 74.3.2,1993,"lEEE Standard Criteria for Digital Computers in Safety Systems of Nuclear Power Generating Stations", Annex E, and ASME NQA-2a-1990," Quality Assurance Requirements for Nuclear Facility Applications". In addition, the program is consistent with guidance for software V&V in EPRI TR-103291s, " Handbook for Verification and Validation of Digital Systems",
December 1994.
I i
2 e g -
Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting ;
Question 7:
l.
What is the methodology used to confirm that hydraulic modeling actually represents the hydraulic profile at the LEFM installation site? -
Answer:
Hydraulic modeling is performed using the chordal LEFM spoolpiece and a geometric scale model of the actual hydraulic configuration at the installation location and for a
! significant run of piping upstream of that location. Any piping characteristic which may influence the profile at the installation location is modeled as discussed on page F-5 of
, the Topical Report. [
i 1
l l
Attachments: I
- 1. [ - ]
I Additional Clarification Requested: )
l Add a discussion on the practices used by Caldon or required by licensees to ensure that as-built plant configuration is modeled correctly. See page 4 of 8 of LER 94-001-01.
Answer:
l Caldon requires an initial physical plant walkdown to either identify a suitable location for the LEFM or to ascertain that the proposed location is appropriate, considering both the upstream hydraulic configuration and access restrictions for installation. As part of l-l this procedure-controlled activity, the plant's isometric drawings are checked against the l as-built configuration. The LER referenced in the question refers to a flow meter installation which has a bypass line around it, and which permitted some feed flow to bypass the measurement section. This location would not be permitted for an LEFM/
installation, by Caldon procedure.
I l
. . . _ _ . .-.m.- _ . _ _ . _ . _ . . . - . _ . _ . _ _ - . - _ . _.. .. _ ., _ ._ _ _ __. _ .. ~ . ._ _ _ _ _ _ __ _. _ _ _ _ . .
l l
Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting
- - . Question 8:
1 V Is coherent noise constant and [ ] an adequate indicator for coherent noise?
i l Answer:
l l [ ] (This answer is proprietary in its entirety.) ~
i l
t i
Attachments:
l l 1. [ ]
Additional Clarification Requested:
l None. i l
l i
l I
i ,
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r
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Responses and Furth:r Clarifications to NRC Questions from September 29,1998 Meeting .
Question 9:
- (7-N._)
L Clarify that the 0.5% used in the Topical Report is 95% confidence level (2c).
l Answer: )
l l The 0.5% mass flow uncertainty stated for the chordal LEFM and the LEFM/ is a 2 standard i i deviation (20) uncertainty; that is, it represents a 95% confidence interval. This is intended to be l a bounding approximation. This subject is discussed further in response to Question 13.
i Attachments:
- None.
Additional Clarifications Requested:
None.
.A i
I I
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Responses and Furth:r Clarifications to NRC Questions from September 29,1998 Meeting 4
i Question 10:
i l How does the LEFM/ uncertainty compare to the venturi uncertainty at Comanche Peak, in measuring reactor thermal power?
i
. Answer:
l
) '(. }
- Attachments
,1
- 1. I I i Additional Clarification Requested:
2: ,
' None. l 4
l
- i I
- i a 1 e
1 l <
s l'
i-i l
i a'
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.. - --._..... .._-.-. - - . ~ . . _ . _ . _ - . _ _ . . ~ . . . . -
Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting f
Question 11:
l V Confirm equations in A-19 of Topical Report for venturi. There appears to be an extra term.
Answ er:
Page A-19 contains three typographical errors, none of which affects the calculated result Page l A-19 is intended to explain the algebra behind the combination of errors for Table A-1, on page A-20. Both pages are attached to this answer sheet for clarity, and the typographical errors on page A-19 are so marked. Note that there are no related errors on page A-20.
Attachments:
- 1. [ ]
Additional Clarification requested:
None.
l l
l t
i AJ i' 1
Responses and Further Clarifications to NRC Questions from September 29.1998 Meeting l
Question 12:
~
- Does cross flow == transverse velocity?
Answer:
Yes. For the purposes of this report, the terms are used interchangeably.
i Attachments:
None.
Additional Clarification Requested:
L None.
t-
{
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Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting
]
_ Question 13:
i l Clarify the usage of 2a and 95% confidence in the Topical Report.
1 Answer:
The thermal power uncertainty is calculated as a 2a uncertainty, or 2 standard deviation 1 uncertainty, with a 95% confidence interval. The calculation is performed in accordance with l ASME PTC-19.1, which states that,"when a 95% uncertainty interval is constructed for each sample, the intervals will contain the true value 95% of the time in repeated sampling", Further, the standard confirms that root sum square ofindividual error contributors will provide 95%
coverage when neither bias error nor precision errors are negligible compared to the other. This result is supported by Monte Carlo simulation which is referenced in the standard. l I
1 I 1 Attachments:
1, [ ]
Additional Clarification Requested:
None.
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Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting l
i 1
7 Question 14:
'( )
l K./ Provide the references sited in the temperature correlation uncertainty and an explanation l of the field data provided in this analysis.
Answt r:
Copies of each of the references are attached. ,
l The field data provided in the Topical Report was based on over 45 individual comparisons of LEFMs and nuclear power plant RTDs temperature inc" ations. All comparisons were based on at least 15 minutes of data from both the LEFM and the plant RTDs during a period when the feedwater temperature was constant. Only a single comparison was made for each pipe. In every case,'the feedwater temperature was between 380 F and 465 F.
l In the vast majority of the comparisons, the plant RTDs used were the same ones used for j measurement of final feedwater temperature for calorimetric power determination ,
purposes. Typically, these RTDs have accuracies of 1.5 F-5 F. The majority of the LEFM data was collected by extemal LEFMs. External LEFMs measure temperature based on the same principles as the LEFM/ except the transducers are mounted on the outside of the pipe. The remainder of the LEFM data was collected from Model 8300 chordal LEFMs. [ ]
',O
( ,/ Since the Topical Report was prepared, additional comparisons have been made of LEFM and plant RTD feedwater temperature indications. Figure 14.1
- picts a histogram including all of the LEFM/ plant RTD comparisons available. In all, there are 65 individual comparisons between LEFMs and RTDs of feedwater between 380 F and 465 F. The average difference between the LEFM and RTD indications in these comparisons is -0.03 F. This strongly suggests that there is no significant systematic bias in the LEFM temperature correlation, corroborating the analysis in Appendix C of the Topical Report.
Attachments:
- 1. [ ]
- 2. Greenspan, M. and Tschiegg, C.," Speed of Sound in Water by a Direct Method,"
Joumal of Research of the National Bureau of Standards,59:4, October 1957.
- 3. Wilson, Wayne D., " Speed of Sound in Distilled Water as a Function of Temperature and Pressure," The Joumal of thw Acoustical Society of America,31:8, August 1959.
- 4. Barlow, A. and Yazgan, E. " Pressure Dependence of the Velocity of Sound in Water as a Function of Temperature," British Joumal of Applied Physics, Volume 18,1967.
- f. Barlow, A. and Yazgan, E. " Phase Change Method for the Measurement of Ultrasonic l
i Wave Velocity and Determination of Speed of Sound in Water," British Joumal of Applied Physics, Volume 17,1966.
O v
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. . m. . _ _ _ _. __ . _ ._ _ _ . _ .
.=
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Vol '9. No. 4. October 1957 Research Peper 2795 , .?
.., Srnel or s. srch of the National Baeau of Standards
( ,.
c
> % W Speed of Sound in Water by a Direct Method' -I I -
" Martin Greenspan and Carroll E. Tschiogg b The speed of sound in distilled water was measured over the temperature range 0* to 4'k 4. I
- .~ to0* C with an securaev of 1 part in 30,000. The results are given as a Afth-degree poly- **-
nomial and in tables. The water was contained in a cylindrical tank of Ased length termi-nated at each end by a plane transducer, and the end40-end time of Sight of a pulse of sound $
was detertained from a toeasurement of the pulse-repetition freqieency required to set the el
' ]!'j I
-*f. successive ceboes into time coincidence.
owe .
1 as the two with which ulses thehave coincidence different aba F. 1. Introduction setcould would b'e bes,' the h ac
~
The speed of sound in water, e, is a physical very poor. Instead, the oscillator is run at about Li
- E 3
it, together with hall this frequency and th'ecoincidence to be set is
~ ~
pmperty of fundamental interest;ic the density, determines the adiabat compressibility, that among the first received pulses corresponding to b- l u l r; and eventually the ratio of specific heats. The vari- a pc.rticular electrical pulse, the first echo correspond- '
ation with temperature is anomalous; water is the ing to the electrical pulse next preceding, and so on. Ll 3 J.
Figure 1 illustrates the successive signals correspond- *J 1' only pure liquid for which it is known that the speed ' 4 j A of sound does not decrease monntonically with ing to three electricalinput pulses. The input pulses r; '3 7 fall halfway between the pulses for which the coinci-
[3 temperature.
There is also a practical interest in e in that water dence is set, so that they do not tend to overload c! Mj jg 'f the amplifier or distort the oscilloscope traces. The lI is used as a standard liquid for the enlibration of ,1 period of the oscillator, when pmperly set. multi- '9 i im ~
instruments that measure the epced of sound in 4
plied bv twice the length of tne tank, as the speed of'i l
- . liquids automatically, both in the laborntory and in
~"
the field. In feet,it'was in connection with the cali- sound in the sample.
figure U 8 that our interest. The oscilloscope trace actually looks like that E
.htttb@ bration of such "velocimeters"[1]In in this work was first aroused. the first place, shown in the inset (6g.1). The first cycle corre-hr u m -- the available data scatter widely, as recent sum- sponds to sound reflected from the inner faces oniv g
[ ,}'
maries (2, 3) clearly show. In many cases, the dis- of the transducers whenas the succeeding cycles gg LI A#
89 correspond to sound reflected one or more times from i-8- crepaneses far exceed the claimed accuracy or at an outer face. Therefore, the coincidence is set bv l
\' trlier in7 least the precision of the methods, even when the s based k methods compared are the same. In the second maximizing the peak on either the first or second i i place, there exists no set of data that gives a smooth balf-evele; the same result is obtained in either case I'
.i variation with temperature over any considerable but the second half cycle is easier to use because it, range. In particular, the best of these data yield is bigger. What we are measuring here is the speed ma s l
S. . calibration curves for our velocimeters which are corresponding to the first arrival of the signal;hase I x1 from y badly curved instead of straight (as they snould be), nondispersive liquid this is the same as the p L and about which the data scatter irregularly, but velocity. It is true that the coincidence is made at a q reproducibly. The results here presented are free of <
M.
(6)q these objections.
~~ ~ * '""""
yo, d i 2. Method I o I X 10-'t l At the top of 1 is a schematie of the a n.
I 8'"188'l ratus. The sam is confined in a tube of w$ch so e . sa., <
the ends are plane, parallel, electroacoustic trans. %, _._ ., "**"" * " '
I ducers quartz erystals in this case. If the left-hand j
< is excited by a short pulse from the N; crystal, say,llator, t,he oscilloscope, which measures blocking osci
- m. Soc." I the volt. age on tne right-hand crystal, will show a l
-L received pulse and a series of echoes, as indicated 0 l l I 5
sh NB8 $ in idealized form on the line below (fig.1). The '
'h NB6 I pulse repetition frequency of the blocking oscillator is controlled by a sine-wave oscillator and if this 0 l 1 1
- b NB8{itfrequency were adj,usted so that each blocking oscil-lator pulse coincided with the first received pulse of J .
0 l l J the next preceding cycle then the oscillator period would equal the time of fb,ght of the pulse. However, ,
l ,
gry pyy=4 m pn >< sb. onc. .t xa na ne==<ca ==4ar - -. -- = = a. a. a -= = =i-i -
.r . . u,,. ,., . . m4< = w.r.
249 O
O
y w =- w w r a .n
"~) ,
time e n-f:urth or three quitters of tiu transducer j
period liter than tne tima cf first arrival, by which 1 L The elects time thire is cpportunity f:r sound traveling by
- Part, conv$n-r patas other than the shortest to affect the location of the maximum. Ilowever, the results are inde-pendent of wnether the first or second half evele is i.
h- <
l pulse fonntnl ptter. In a4 mth Ene in J&
14 I thev are also not affect,ed by substituting 9ethin the n V used;ls crysta of twice the thickness, or by diameters of the tank, or of the hot electrodes.
the changu,fhese - % must be, -
bhange duru:
+ results lead us to believe that the error introduced by '
~.k g-. .
~ .
e count by ligible. .
The biocs this maximization technique is n3 aiso in another 4
The question has been examin way. Suppose a coincidence to have been made at M ~
high and 0 yby a large,is frequencyf; others can then be made at submultiples uon oi a squ of f. At the frequency f/2 for instance, the first - - --------b-----..L- .... .
hocas 2. Delay line, dissemnM,d. pwave geners received, pulse corresponding to a particular input e the mak = tae Wari arwam en.= th. anme s.i . ..e .iis. 4,,,,
Sy means of pulse coincides with the second echo (not the Erst, ****"'"'"'"'""*"'"******""*
as before) corresponding to the electrical pulse next *** .ry. *d"
- E " " M "4. ;
f The recei t.h of,lo a i preceding, and so on. Effectively, the sound pulse <
e, m this . ;
is timed over a path twice as long as before. It is 1 high4ng r 6
found that ttie measurements atf and near f/2 are t sweeps 1 substantially identical, so that the error in question ' cillator tt r is less than, or at most comparable to, the experi- y elay time s ;
mental error of the time mrsaurement.
32 Ten
- 3. Apparatus I 3
- k. I The dela f
3.1. The Delay Line
[ h4 d i ly imm
. The A tirrers,3 h !
The disassembled delay line is shown in the pbc:o- 1 A &
i s a small I graph, figure 2. The length of the tank is about Db [-
4
- 200 mm, and the bore about 13 mm. The filling \
5 \ *s power input water e !
holes are scaled b plugs having Teflon gaskets; a %' -
h stures areol i 1
small hole in one p ug provides pressure release.
- IThe temper !
i The tank is of a hromium steel
- which ~
thin less ? !
treatment, takes a good optical finish, afterhest
. Because I s
uired fo: j g
- this steelis not so corrosion resistant as the nickel- // m O, or > '
' chromium stainless steels, the bore of the tank was 70.03* C; at !
i heavily gold plated. ganuum ' - '
u M4 ithermal coe
- f l The ends of the tank are optically flat and parallel to within less than 1 u. To these ends are carefully
' ther low, i
- The tem: i i wrung the 0.8-mm thick x cut quartz crystals, which ,
= th a plati'
- also are optically flat. The caps, when bolted on, navn s. s,A,.mit er =, ,.a f ran a, ,4,mi., a,,rri ddge. A
- clamp the crystals through neoprene 0-rings. A sad cop eseemNr. n a the <
coaxial cable passes through a sealin cach esp, and j g the center conductor makes contact with the outer gme ssoua seegggg_uithga mgagg I)he platinu f pressure re g (hot) clectrode of the crystal through a light spring. ewareer.).s arefrene o<ms ans e.einw am, l Nading ser* Q The outer electrode is a 9 mm circle of aluminum- nater are s l backed pressure-sensitive adhesive tape. The inner was the tank and heat treated together with ii. ' '
Fmm these data, the length of the sound path i- : ensurerne:
(ground), electrode is of fired-on gold and is about 0.01' 12 mm m diameter. Contact is made through a known to better than 2 parts in 108 at any tempcm-
'I li ht gold-plated helical spring which touches the ture between o' and 100* C. It is, of courm Ltures).
efectrode around the edge and bears on a shoulder necessary that the crystals be wrung down wit h laation w l arences sg The inner electrodes and great care so that the fringes disappear all ammul -
ler so thi machined into the bore.,f spnngs are unnecessarv i the sample has high cou- the peri hery, to achieve this accuracy. The clami- d endings cc ;
ther are ing gaafets must bear directly over the contactme ,
ductavity or a high ilielectric constant;lutions of surface and not spread out over the unsupswrnd ,
E I j usually omitted for water and aqueous so j v.-
t salta. Figure 3 is a schematic drawing of one end area, else the crystal will bend. With these pri- F of the assembly. cautions, the delay line may be disassembled anal Th The length of the tank was measured at 20' C, reassembled repen'tedly with reproducible remilia- Me md u and the coefficient of thermal expansion of the steel If the crystals have been properit wrung on dad $rdinary la was measured on a sample cut from the same bar as clamped, they cannot be removed by hand alH1 c' several days,'but must be soaked off. ' i niI@,",,*' *
.rira.s n.s m.p. m.
no 'g
'i L
O -
p.
" -- a w a- ~
u --- ,
C nnd poured, while still hot, into the preheated tank. -
(s., 3.2. The Electronies '
s - Althoueh dissolved air has a neghgible effect on the
- l. ne electronic circuits (fig.1) are, for the most speed o'f sound in water 14), it is deairable to exclude e pt, conventional. However, the osed,lator and the air and so prevent possible bubble formation on the p
- pid*-forming circuits must,be excepuonally free of transducers. .
.itter. In addition, the osedlator must be provided The other two sam
- i aith fine frequener control, so that it can be set rectiv into the tank. The plestank were vacuum was placed indistilled an ice di. *
, . within the required sensitivit- of measurement, and bath' and connected to a flask of distilled water.
I ; it must, be, so stable that tfie frequency does not The srstem was then evacuated and the water !'
- rhange dunng the counting time by enough to alter alloweil to distill over at about 50' C. .I
- the count by more than one.
The blocking oscillator produces a pulse about 100 The results of the three runs were the same within the errors of measurement; the data were, therefore' dW 7
, li i-high and 0.05 to 0.25 usec wide. It is best driven hv a lage, f ast pulse such as is gotten by differentia-combined. +4 E
l' tion of a square wave derived,in turn, from the sine- 3.S. Technique W8; wave generator.' The jitter may be reduced further The water bath was cooled to just above 0* C, hv means of a narrow band filter after the oscillator. fy
=u,,,,,-
% E',- ~ The receiving circuit consists simply of a short and the heaters were operated at low power to sta- .s leugth of low-capacitance cable, a wide band (5.5 bilize the temperature. , (Below room temperature W p~ .\le. in this case) amplifier of gain 100 to 1,000, and the refngeration machme was run contm After the reachngs were taken, the power put to m,uously
'. ;< 4[
K a high frequence type oscilloscope equipped tnth the heaters was merensed, and so on until the tem- 6
- m fast sweeps. The sweep is triggered from the #
oscillator through a variable delav; the necesser~v perature was just below 100* C. When the tem- y perature was stabilized, as indicated by the con- - 4, delay time is about half the osei!!athr period. '
stancy of the SIueller bridge reading and the near -
3.3 Temperature Control and Measurement zero reading of the thermocouple galvanometer, the coincidence wcs set on the osedloscope by one ob. ..
( ..
.~ The delay line, suspended from its cables, is server and the frequener (doubled for convenience) 2.9 t deeplv immersed in a 27 gal, well-insulated, water was measured bv counting eveles for 10 sec (about -
bath.' The bath is provided with 2 pump-type 75.000 counts) by means of'an electronic counter. "
L
-- stirrers. 3 heating coils, and a cooling coil connected At the same time, another observer balanced and J.j) . ;
to a small refrigeration unit. The ternperature of read the SIueller bridge and read the thermocouple &
c the water adjusts itself so that the losses equal the galvanometer deflection. . $"
O I power input to the heating coils, and various temper- While the temperature readings were being made, the coincidence was independently se& and the re-
- 4 -
t atures a re obtained simply by varying t he power input. : h O The temperature is, by titis means, easily held to sulting frequency measured three times or more. Q othin less than 0.005 deg C for the interval of time The vanous readings were alwavs within the 1 g.
1 required for the measurements, except that above count inherent error (even for different observers) d. j .
75 C, or so, the variation may become 0.02* or and the modal value was recorded. This, divided -
0.03* C; at the higher tempentures, however, the bv 20 and multiplied by the length of the tank at [: - I N-@j'- thermal coefficient of the speed of sound in water is tfie particular temperature, was taken as the speed i. , t
~
rather low. of sound. e, correspondine to the temperature, T, i (, ;
'O The temperature of the bath water is measured obtained by calculation from the platinum ther- 1.
b U with a mometer and the thermocouple readmgs and the as- H i '{
tre crydelf Bridge.Aplatinum differential resistance thermocouplethermometer and 11ueller has one junc- sociated calibration data. All temperature calcula- Q 3 m tion m the sample in the delay line, and one tied to tions were made to the nearest 0.001* C and the final - ;
the platinum thermometer; it passes through the result was rounded off to the nearest 0.01' C. bc. 4 ry"w"*'.
i .t . pressure release tube (fig. 2). The thermoccuple In order to insure that the coincidence was set on I-
! d 5
.; reading serves to indicate when the samp'le and bath the proper evele,it was first set approximately, using r P: c with itM , water are substantially in thermal eqtu'hbrium, and the coarse frequency control at a moderate sweep t<
path isJJ measurements are made when the discrepancy is less speed and low oscilloscope g,ain, so that the entire I'! ,
d ;11 empera-w than 0.01' C (somewhat ester at the high temper- pulse was visible on the screen. The sweep speed atures). The t.hermocou e and galvanometer com- was then increased while the delay was readjusted n E !
course.1
.n with 1 bination was calibrated or small temperature dif- to keep the proper cycle centered. Next, the gain '. E around y ferences against the platinum resistance thermom- was increased wtu'le the base line w&S moved off the " 9 screen to keep the point of extreme deflection cen-i clamp- l[ eter so that small corrections to the temperature itac readings could be made. tered, and the amplitude was then adjusted to a '
l maximum using the fine frequency control J p.;
ppo ~3 se pre .{ 3.4. Samples ; ,
ed and results.3 The measurements here reported were made on 4. Results ]n l
?
a three separate samples of water. One sample was on and v ordi sary laboratory distilled water. This was boiled From readin taken at 83 temperatures between ( s d aftera r 0.14* and 99.g6* C, the calculated values of the "
l n'.Er*,0lM Tl%"o'"n'YsYo*2,TN.@C
. speed of sound were fitted by the electronic com- g ]
,m f :.
251 h b l [
summmmmme n m v _ - - - _ - _ _ - - _ _ _ _ _ _ _ _ _ _ - _ - _ .
F.
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it;
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a e r
m e m m a m ,
y' tjf Tewenansie .*C u as r Frot ms 4. Devistiens, r, of egustievi J frossi de data.
U 3 puter SEAC by the method of least squares, to a significant figures, so that on account of rounding.og g R errors, the tabulated differences in some cases differ a a fifth-degree polynomial, .
e by om, unit in the last decimal place from the dit. .
(1) ferences of the tabulated values of c. It is believed E E e-g* a,T'. (see section 5) that the systematic erron do not a si exceed 1 part in 30 The tables should, then.
The reduction in the residual sum of squares over a I following manner. In table 2. . " i ri,,
fourth-degree polynomial, due to fittmg the fifth. 1m. re, be used mbthe'000.
i i
ear mterpolation should performed to the .,
degree term, was statistically significant at a prob- nearest 0.01 m/s and the final result rounded off to abilitt level less than 0.005, and tho deviations of 0.1 m/s. The error will then not asceed 3
a the nearest,t in the last place, s. e.,0.05 m/s. Linesr ---
the data from the statistically significant in fifth-debe tion of lack of random- interpolatton ,in table 3 will vield erron that do not polynomial showed one-half no um
.e r l e ness. The deristions are plotted against tempern. exceed 2 units (0.2 fps) m the 'ast place. e-ture in fi ure 4. I *# '
d The raines of c,in eq (1),for e in meters per second (m/s), and T in degrees C, are: a,-1,402.736; ai= S. Discussion ~g .
5.03358; e,= --0.0579506; ae3.31636 X 10-*: a -- Followin is a list of the known possible sources n l 8
1.45362X10 ; and a ss=3.0449X10, . The stand- of error ank an estimate of the upper limit of each I 88 ard deviation of the measurements is 0 0263 mis, or * ' ' l. E i about 17 ppm. Estimated standard deristions of
.he values of c predicted by eq (1) were er.!culated S.I. Frequency y ;; g" G for five representative temperatures. The results As already stated, the frequener was measured by 4 "1 V
f are given in table 1. counting efeles for 10 sec; the" total count was 0 gj y Eadimeled slendard drytefio4 (8. d.) Of FelkN Of C about 75,000. The inherent error is I count,bui .[ g; y TAs1.s 1. in all cases the mode of at least three mdependeni ,
predteded 6y egnation J readings. of which at worst, two were the same and H ;' ,, ,
the third different hy one, was tsNen as the obseTYed y ,
'rumperanisre s s. ralue. The counting error can thus be as est as . . .
1 part in 75,000, but as it is random, the ekect on I *;
.c w, , , . L M
'gy the final results is negligible, as indicated in section 4.
3l [j The 10-see time base was obtained by division frorn i e 2l j e : ass ae is :E5 !! a 1 Me crystal oscillator which is sta61e to 2 parts in 1
! #i 10' per week, and which was compared with signals .<
Table 1 and fi re 4 make it clear that eq (1), IM'" N Of I. rom a local precision standard. The l( . *ijJ crrors due to maccuracies m the time base are. 3 i together with the sted constants factory interpolation formula theand errorsprovides intro.
therefore, also negligible.
a satis- g.
duced by its use are small r' elative to the possible S.2. Wih of Path -tank 'is abou systematic errors of measurement (see sectiou 5). i >
P,'",',"d a ven in ts.bles 2 and 3 were calculated The length of the tank across its polished endt ni The 20* C was determined within 31, i. e.,5 ppm. Thei 1 Yhe from values eq (1) f'y SEAC. mal expansion measurements were made at 20',60,.
uest Table 2 i res the speed of sound in meten per N ref the sound accond for o a degree C from 0 to 100, and table 3 and 100* C; the lenkths at intermediate tempera. j 'between the g'.vss the speed of sound in feet per second at inter.
tures were calculate by quadratic mterpolation- mates to thi vals of 2 deg F from 32' to 212' In each case, the The maximum absolute error in the thermal exlmn- -
Nhich the differences, which are listed for convenience in inter-sion coefficient is estimated at 0.2 ppm; this arrT 8
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are, a. r E Thus, the total uncertainte in the length of the attention to avoidance of clamping pressure too near [
tank is about 5 ppm at 20' C, and increases with the unsupported areas of the crystals, the crystals U 1emperature both wan; at O' C it becomes about might deflect enough to cause verv sizable errors. kj da a[ 9 9 m and at 100* C,'about 21 ppm. The present design makes it possibfe to disassemble [ ,
Thar . I lie pestion arises as to how closely the length entedly without
' 60 '
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d mates to the length of the tank across the ends to are 0.8 mm thich, are replaced by crystals 1.6 mm '
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%..i. . .
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n
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.~ . ._ - - .
i ,
?
S.3. Setting th) Coincidince const:nt at this v:Jun cut to 70* C, and nses to burnd d Reneon about 35 ppm et 100' C. It is upon these considers.
As expl .ined in section 2, it is believed ilnt no t ons that the recommend:tions far the use of the
, measurable error is introduced by the technique of maximization of the accend half cycle of the received tables in section 4 are based.
The values of e here reported are lower than those Pat g pulae. However a word should be said about the of most other workers, in particular the value at I t i effect of personal bias on the part, of the operator. 30' C is about 0.4 m/s below that of Del Grosso, I C/ 9 The operators report, to varying degrees, tendencies to adjust not only for maximum height of peak, but Smura, and Fougere l31, whose work with the ultin-sonic interferometer is perhaps the most carefulk I
l also for maximum symmetry and sharpness of peak. planned, e.xecuted, and analvzed work of this typ'e l Long e.xperiment has convinced us that any of the to date. It was, therefore, f'elt desirable to perform three enteria lead to sensibly the stane result, so an independent experiment using an apparatus and '
that although different operators weigh the three a method as different as possible from those of both -
critena differently, ther reproduce each other's Del Grosso, et al., and ourselves. An apparatus I settmgs so well that the discrepancies are negligible was constructed with which it is possible to measure. ,
y relative to other sources of error. The assumption as a function of distance, the, phase on the aus of a is implicit that the errors of bias do not much exceed beam of progressive waves emitted bv a small piston.
the discrepancies among individuals. like radiator. If the wave were plane, the phase , [ The radiat
.ntennas has S.L Temperature would speed cvarv linearly would nith be 2rfil, wheredistance f is 2, frequency.and In I fears the phas 11-6).'
the present case, the wave is not plane and the slope jnoblem woul '
The Afueller bridge with which the resistance of of the curve 2rf2 versus e depends on z and on the $n which the the platinum thennorreter was measured has a least geometry of the arrangement. However, the theorv Idaquatelv r count of 0.0001 ohm corresp'ondine, for a 25-ohm enables us to select a distance i. of the receiver froth ose radius thermometer, to about 0.001 C. 'The bridge was the source such that for r>i. the departure of cal curvattu calibrated internally so that the indiented resistanec 2rfdr/d, from e is as small as desired. formal sc in terms of the internal standard is correct to about 'Five runs were made in distilled water at tempera- assical hart 0.0002 ohm aside from temperature effects and slow tures between 15' and 25' O. The priccipal un- tegral ordt drifts in the arm ratio and in the zero. Allowing certainties are thought to be first, one of nbout 40 ery poorly for these, it is estimated that the bridge error does ppm corresponding to a possible ermr of 0.01' C in pared to i not exceed 0.005' C; crrors in the calibration of the the temperature, and second, one of about 56 ppiu own alteri platinum thennometer itself and those due to heating related directly to the innecuracies of the screw with Twhich can b by the bndge current are much smaller. Afore im- which the receiver displacement was measured. Jn the illumu portant is the error that arises from thermal gradients These are independent. However,in the worst case cotics is mos in the hath. On the assumption that this does not of the 5. the result differed from the value gotten % rigorous exceed half the reading of the differential thermo- from table 2 bv oniv 27 ppm. The value of Del rapidir e couple which, it will be recalled, measures the dif- Grosso, et al. [3l disagrees with that of tahic 2 by 272 The caleu ference between the temperature of the platinum ppm. ounted ant element and that of the sample, an upperlimit to the This work will be reported in detail elsewhere. p t-shadow
()
,~
( corresponding uncertainty in the speed of sound, et er geome
/ e, was calculated at various temperatures from, the onner case The authors are grateful to the knoni thermal coefEcient of c. This u er hmit Enginecruig Aletrology Section is zero at 74* C, where e is stationary angmeicases Section, m whose Laboratones the length an[ersonnel of the Lencth g/jtter ca of the of the tank
% espiteactus k uld steadil m both directions, reaclung and its thermal expansion, respectively, were men #- the at o' , and about 14 ppm at 100 C,about 25 ppmured. Thanks are particularle due to Joseph 31. q a me, it Cameron of the Statistical Eugineering Section who < $""2""
S.S. Purity of Sample adnsed the authors on problems of data processing. .
p it is de=;
~
- "d Because the results obtained on ordinary labora- 0" g -
performed the curre-fitting computation
- ile es tory distilled water were inchstinguishable from those F obtained on the same water re' distilled in vacuum 6. References t g directly into the apparntus. it is felt that the remain- [1] Martm Greenspan and Carroll E. Tscluess, su s.oroumi . E mg impurities do not have a measurable effect. ultr..ome velocuneter for bquids, Rev. Sci. Inst e . i i A thin a Several measurements made on local tap water gave . Age $nneu and W. r. Mruk Microneoustic uur- cfinite len results about 30 ppm higher than for distilled water. feer usms ao Me pubes. J. Acoat. Soc. Aum [sidered bec 27, 672 (1954). = radiation fit 5.6. Ovier all Accurney pl V. A. Del Grono. E. J. Smura, and P T. Tougere. Accuf[- and coax
, acy of ultrasonic interferoteeter determmations. nil !
From the foregoing discussion it appears that the I g " g ,,Na,'j3 h* **% ""
major sources of error are the uncertainties m the 33 pl Marun creenspan and Carroll E. Tsetuer.g. Effect of } length.M yoit Tt
- length of the path and in the temperature. Both of dic.olved nar on the er med of *o"nd m water, J. Acou-' h" I terms of s these are temperature dependent; their sum is an Soc. Amer 28, 501 (1956). g._
upper limit to the total error. This is about 35 ppm at O' C;it falls to 15 ppm at 40' C and is almost Msurmov, Sfarch 27, lh,,
4, %.
- j. .
e A
hw --: _
I k G
m (V) i THE_OURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Volume 31 M l Number 8 AUGUST 1959 l
Speed of Sound in Distilled Water as a Function of Temperature and Pressure WAYNs D. Wttsow 4
U. S. Naal ordanace laberosary, White 0ak,3Genr String, Maryland (Received January 26,1959)
An ultrasonic pulse type apparatus was used to ====re the speed of sound in distilled water over the pieesure range 14.7 to 14 000 peia and the temperature range 0.9 to 91.2*C. The temperature where the maximum sound speed occurs shifts to a higher temperature when the pressure is increased. At atmospheric O pressure the computed maximum speed was 153536 m/sec sad occurred at a temperature of 74.164*C.The
( isotherms of sound speed, plotted as a function of pressure, are concave upward below 20*C, concave down.
ward above 20*C, and are approximately linear near 20*C for the pressure range of 14.7 to 14000 paia.
'Ibane curvatures have a maximum value of 1 part in 300 compared to the estimated accuracy of rnan-re-ment which is 1 part in 10 000. 'Ibe results are presented in tables and also in the form of a fourth degree equadon 6tted to the experimental data by the method of least squares.
L DrTRODUCTION to determine sound speeds in water within the tem- l A distilled water is important for the computationPRECISE knowledge 14.7 psiaSPS14 000 psia. The present of the paper is con- speed of many thermodynamic quantities. Numerous meas- cerned with measurements in distilled water. Numerous
'trements have been made of the speed of sound but systems have been designed for sound speed measure-only a few measurements have been made of sound ments but the fixed-path double crystal"velocimeter" speeds as a function of temperature and pressure, was selected by NOL as most suitable for measure-Greenspan and Tschiegg8 and also Del Grosso2 have ments under pressure.
published accurate tables of sound speed as a function of temperatun at atmospheric pressure. The eHect of IL EXPERIMENTAL ARRANGEMENT l pressure on sound speeds have been explored by The method used in this work is similar in principle Holton,* Smith and Lawson,* and by Litovitz and to that developed by Greenspan and Tschiegg at the Carnevale,' and others; however, diferences exist be. National Bureau of Sta tdards. The water sample is tween these data. Consequently, measurements have contained in a tubular housing, each end of which is been made at the Naval Ordnance Laboratory (NOL) terminated by a 5-Mc quartz crystal for the transmis-l sion and reception of sound pulses. A knowledge of the i M. Greenspan and C. Tschiogg J. Research Natt. Bur.
S N 59,249 (1957); also . Acoust. Soc. Am. 31, 75 repetition rate of the pulses when echoes are super- l imposed is sufficient to determine the time required for i V. "A. Del Grosso, National Ramearch Laboratory Rept. No. a sound pulse to traverse the length of the veloctmeter.
4002 (1952).
a G. Holton. J. Appl. Phys. 22, 1407 (1951). An accurate determination of this length then allows
. A. H. 5 math and A. W. Lawson, . Chem. Phys. 22,351 (1954), the velocity of sound to be computed.
sT. Litovits and E. Carnevale, . Appl. Phys. 26, 816 (1955).
V The main differences between the velocimeter used 1067
/ c.oment e rose irr the W Seemy of Amanca. /
1068 WAYNE D. W i !. S O N l p
- a
- 5 <t M h. b_, Figure 2 presents a block diagram of the electronic instrumentation required for the sound speed measure.
gg o s s ) L qg Ls s N-Ny El*, ments. An interpolation oscillator equipped with a 6ne j
I fd frequency control is tiltered electronically and used to N1
- N'
- control a pulse generator. The pulse frai this generator is shaped by a blocking oscillator to furnish a pulse of l
\ gN** ,.
180 v amplitude with a duration of 0.05 asec to one l 'e crystal in the velocimeter. The second crystal receives the pulse after it has traversed the water sample and Fic.1. Schematic of velocimeter: A, test chamber: B. quarts crystal: C,0-nng seal; D, compranion spnog; E, e6ectncal lead; feeds it into preampli6ers prior to displaying the sign
,- E benows. on an oscilloscope. Co!ncidence of the sound pulses in the velocimeter is adjusted by observing the signal i
by Greenspan and Tschiegg and the velocimeter used trace on the oscilloscope while varying the oscillator at NOL are as follows: (a) the Natanal frequency. It is this frequency which determines the Standards (NBS) instrument was 20 cm lengthm, as Bureau of time required for the p.ulse to traverse the liquid in compared to 12.7 cm for the NOL instrument: (b) the velocimeter. The pulse repetition frequency is doubled NBS instrument used 3.5-Me crystals and the NOL and displayed on a f requency counter with an accuracy
! instrument used 5.0 Mc crystals; and (c) the NBS in- of 1 part in 100 000 for the computation of sound stament used crystals which were wrung to the ends y,goe;ty, of the tube without electrode plating at the contac Figure 3 shows the general arrangement of the com-area while the NOL instrument used gold plat plete instrumentation for monitoring and accurate crystals. The NOL velocimeter, shown in Fig.1, is a control of the physical environment of the velocimeter. {
stainless steel tube with a bin. bore approximately The pressure vessel containing the velocimeter is placed !
5 in. long. The two ends of the tube were machined in a 110. gallon constant temperature bath regulated !
i plane parallel and perpendicular to the axis of the tube by a mercury thermoregulator. Three stirring pumps !
to an accuracy of 0.00005 in. To each end of the tube are used to circulate the water in the bath to assure a l is attached a cap containing a 5-Mc gold-plated X-cut constant and uniform temperature. The absolute tem-crystal backed up by a Mycaler insulator and a com- perature of the bath is measured by a platinum resist.
pression spring. The springs are used to force the crys- ance thermometer to the nearest 0.001*C. Temperature tais against the ends of the tube when sanmbled. A variations and temperature gradients are recorded by neoprene 0-ring louted between each crystal and the the action of a thermistor placed in the bath near the tube provide leakage seals. This 0-ring is deugned to pressure vessel. The thermistor acts as the resistance in !
i compress fully under the force of the spring and allow one leg of a Wheatstone bridge; the unb: lance of thh l the crystal to make uniform contact with the ends of bridge is observed on a recording potent.ometer and !
the tube. One end cap contains the electrical leads for variations a temperature of 0.0005'C ne easily de. i tected.
the communication of sound pulses between the crys-tais and the external electronics, and the second end In Fig. 3 a single meter is shown as the device used cap has a bellows attached for the purpose of trans- to measure pressure. Actually, a manganin resistance mitting the pressure to the water sample inside the gauge, a sensitive Heise gauge, and a dead weight tube. The bellows was carefully daigned to insure a tester were used to determine the absolute pressure. j negligible pressure diferential between the hydrostatic Greatest reliance was placed on the dead weight tester pressure 6 eld outside and the pressure inside the veloci* since the manganin cell was unstable at low pressures; meter. The velocuneter is placed inside a heat treated this cell was used however to detect changes in pressure steel pressure vessel capable of withstanding 100 000 as small as 4 psi for higher pressures. It is estimated psia. This vessel has steel end plugs, one of which is used that the absolute pressures were known to within 7 psi to transmit pressure to the inside of the vessel and the or, when referred to velocity coordinates, the pressure other to bring out the electrical leads. A medium grade was known approxirnately to 1 part in 20 000.
oil is used to convey pressure from the pressure gener- IIL METHOD OF MEASUltEMENT ator to the pressure vessel.
Sound speeds were measured by 6rst adjusting the bath to a particular temperature and then by varying
,u ; ' ,,g,,,,, ~,",f"*.b- the pressure over the desired range. Since an adiabatic l .ar sagn m
} increase in pressure of 2000 psi will change the tempera-
' **=sa lsepir.J '"" j ture inside the velocimeter nearly l'C it was necessary i I' to wait until thermal equilibrium was reestablished i carta j ka'a'"' * ,u,,,e. ,essprut before a measurement was made. The thermistor used an ='
to measure temperature was located outside the pres-Fac.1 Diock degram of instrumentation, sure vessel and was not sensitive to changes inside the
SPEED OF SOUND IN DISTILLED WATER 1069 3
(V
.e...,
n.
- o... 4 - - "-
.. y v e nos risamoans omaa 88HsR8E Lt.8-9 Fic. 3. Schematic of experi-yl n .p mental setup. l
/
f 3
f i,l ,p Q
4.'
W"' m = d ~~
d_-if( j ,
."M q4 fca.oruu.m
-_=--
, nm ..rwe nuit
_. +
==
4{w$,
. -w " _ cg{]
, . e .
.m m s
. .m m mmmm m m m s mmmmm mm m m u m mm m_
velocimeter. Hence the sound speed measurement itself tion obtained to describe the coefficients of Eq. (1),
was used to determine when thermal equilibrium ex- The speed of sound in distilled water is therefore given
'sted. That is, the measurement of sound speed over a by period of time (approx 1 hr) was used as a thermometer C=ae +a T+as P+a:P+ asp, to determine when thermal equilibrium was estab- (1) lished. After thermal equilibrium was reached ten *
measurements of the pulse repetition frequency were
,,,,g (gpi, recorded and averaged to give the time required by ,
the pulse to traverse the velocimeter. The pulse repeti-tion frequency is obtained by superimposing on the T is the temperature (*C), P is the absolute pressure a=Allmpe the peaks of the first half-cycle of all echoes (p5ia) and the computed (66)f values are given in in the velocimeter. Table II. The parentheses indicate a set of 64 values n .
associated with each as; for example, Table Il gives th W.RES m S se= 1402.859+1.050469X10-'P+1.633786 The measured values for the speed of sound as a function of temperature and pressure are presented in X 10-'P'-3.889237 X 10-uP8, etc.
Table I. These values are plotted in Fig. 4 with tem- An IBM computer was used to compute sound speeds perature as the absetssa and in Fig. 5 with pressure as from these equations and the results are tabulated in the abscissa. In the determination of the sound speeds Table III. The standard deviations of the differences recorded in Table I, corrections for the change of between the computed curves and the measured curves length of the velocimeter due to changes in temperature for four pressures are given in Table IV.
and pressure have been applied. The results of Table I were used to obtain empirical equations for the speed V. DISCUSSION OF RESULTS of sound as a function of temperature and pressure. It may be noted in Fig. 4 that the manmum sound Equation (1), a fourth degree equation, was first ob- speed shifts toward higher temperatures as higher tained by the method of least squares for each of the eight curves shown in Fig. 4. The coefficients of the pressures are considered. This behavior agrees with the results obtained by Smith and I.awson, and also by eight equations were tabulated and a third degree equa. I.itovitz and Carnevale.' The temperature for the peak Tastz L Measured values of the speed of sound in distilled water.
Temsersture *C usia o.oi* 2.n* 10.20* se.es* 29.es
- Jo.42' 4 ear
- so.se* ee ee* rs.to- on tr*
14.7 1407.41 1416.35 1449.05a 1481.63 1509.37 1528.36 1542.60 1551.01 1555.02 1554.90 1549.80 2000 1429.25 1438.06 1471.46 1504.34 1532.67 1552.03 1567.11 1576.21 1581.13 1581.83 1578.05 4000 1431.66 1460.83 1494.17 1527.38 1555.87 1575J2 1591.22 160l):96 1606.58 1607.97 1605.31 6000 1475.37 1444.42 1517.28 1550.49 1579.04 1599.16 1614.92 1625.21 1631.44 IM3.35 101.75 M)00 1499.72 1508.50 1540.99 1573 19 1602.12 1622.17 IM8.22 1648.91 1655.69 1657.95 1657.36 10 000 1524.61 1533.29 1564.78 1596 90 1625.06 1645.14 1661.28 1672.30 1679.34 1682.13 1682.18 12 000 1549.93 1558.09 1588.75 1620.25 1647.88 1667J2 1684.00 1695.13 1702.55 1705.65 1706.39 14 000 1575.22 1583.15 1612.66 1643.41 1670.58 1690.41 1706.51 1717.68 1725.28 1728.69 1730.02 r%
l 3 * -It a LJ that the peat a la error try +0.4 m/sec.
U
- ..- ...--. . - - - ~ - . _ _-_ - . _. - ._ - ..-.-.__- - ...- .-.-,- . . . -
1070 IVAYNE D. IV I L S O N
( T4sta II. Coetlicients in the sound velocity equations for distilled water.
(u (u.i -==
(4-. (u.
- a. 1402.859 1.050469X 104 e, 5.023859 1.633786X 10-' -3.889257 X 10-58 t 6.138077X10-5 -1.080177 X 10-8 l
e, -5.600577 X 10-* - 1.071154 X 10-* 2.477679X 10-u l e, 2.884942X t0* 2.215786X 10-* - 5.088886X 10-4 1.582394 X 10-' - 2.420956X 10"'
4 -8.238863 X 10-' -6.839540X 10-" 5.086237 X io-"
9.711687 X 10-55 - 1.845198 X 10-*
TAB &a 111. Sound velocity in distilled water Computed from Eq. (1).*
=
Tessersture *C sua o.co* o.w :o.co* Jo.e 40.w so.e so.co* ro.e so w 90.e s oo.co.
14.7 1403.01 1447.85 1482.92 1509.66 1529.30 l 2000 1542.88 1551.26 1555.06 1554.74 1424.49 1470.03 1505.66 1532.92 1553.11 1550.54 1542.51 4000 1567.34 1576.47 1581.14 1581.77 1578.58 1447.24 1492.88 1528.68 1556.21 1576.79 1571.54 6000 1591.51 1601.25 1606.65 1608.10 1605.80 1470.93 1516.15 1551.79 1579J7 1600.17 1599.70 8000 1615.26 1625.49 1631.47 1633.62 1495.36 1539.76 1574.97 1602.41 1623.30 1632.10 1626.88 10 000 1520.36 1638.M 1649.23 1655.68 1658.40 1657.57 1563.60 1598.17 1625.13 1646.19 1653.20 I 12 000 1661.68 1672.54 1679.36 1682.54 1545.72 1587.60 1621.38 1648.15 1668.90 1682.33 1678.78 14 Wlo 1684.44 1695.48 1702.56 1706.13 1706.47 1571.28 1611.66 1644.56 1670.88 1691.44 1703.73 1706.96 1718.10 1725.38 1729.26 1730.10 1728.17
.venner s in m/=c. =
l atma =pheric velocity can be obtained by differentiating temperature exceeding 74.17'C (see Fig. 4). A Eq. (1) and equating the resulting cubic equation to in curvature of the isotherms in the vicinity of 20*C sero. When this is done it is feend that the peak sound has been observed. Below 20*C the isotherms are con-speed at atmospheric pressun occurs at a temperature of 74.164*C. Linear inter,aolation of the results of cave upward, above 20*C they are concave downward, l and in the vicinity of 20*C they are nearly linear.
Greenspan and Tschiogg yields a corresponding tem- Additional measurements at NOL on sea water show perature of 74.178'C. Later work by Greenspan .and that the general efect of pressure on sound speed is 5 Tschiegg* with the sing-around system placed this essentially the same as that for distilled water. This -
mammum speed at 73.95'C. The sound speeds meas-ured at NOL at atmospheric pressure agree well with behavior is in contrast with the results 8 predicted b the results of Greenspan and Tschiegg. The standard Kuwahars'in his tables of pure water and sea water which show the iso-sea water table and byMatthew deviation of the difference between the NBS and the therms plotted against pressure tobe concave downward NOL results for all of the atmospheric pressure data at all temperatures.The sound speeds computed by these is 0.15 m/sec.
The characteristics of the isotherms shownnman in Fig. 5 authors depend on an empirical equation de require comment. At high temperatures it is seen that s for the mean compressibility of sea water, some curves Iitersect; this is to be expected, however, This equation was derived from nman's measure-since the sound speeds at low pressures decrease for ments on sea water and from Amagat's" specific volume measurements on distilled water. Ekman has suggested that Amagat's specific volume data is in error below astuzo =arta
"" " 150 atmos and he applied a correction factor to Amagat's
=se .as data in this range. A descriptive analysis of Kuwahara's i
J m .ng computation is given by Beyer." It is shown here that j'"- ****
- sis the corrections nman applied to Amagat's data were
- in the correct direction although, as Beyer points out, 4 Ve ocat o
- g6& a more accurate expression for compressibility is still
.+ r ,
as a function of tan- desired. nman's equation is accurate to 1 part in 500 gam peratu's and this is what limits the accuracy of Kuwahara's
'""*""'*" ' S. Kuwahars, Hydrocrapine Rev. 16, 126 (1939).
j
- D. J. Matthews, Hydrographic Department Rept. HD 282, j (Iondon,1939).
% = um = as ss == >= == ** '< * ' V. W. Elunan. Pubis, cire. cons, perm. internat. l'esplot.
l respeaanat (*cl la mar. No. 43, 3-47 (1910).
8 E. H. Ama8st, Ann. chim. et phys. 29,68-138, 504-574 I
p e M. Greenspan and C. Tschse8g, J. Acoust. Soc. Am. 28, 500 (1993).
u R. T. Beyer, J. Marine Research (Sears !"oundation) 13, (1956).
113-121.(1954).
l I
i
. _ _ . _ _ _ _ _ _ ._ _ _ ___ _ . . _ _ ~ . _ _ . __ . .- . _ . . _ _ , __. _ _ _ _ . _ _ __
h SPEED OF S O t! N D IN DISTILLED WATER 1071 V work. Del Grossets has called attention to an error in Taniz 1V. Standard deviation of the diserences between a Ekman's pressure determination which is of sudicient pend
- *P" ' ""' ""P i 8 **' * "' '"
magnitude to explain the 3.0 m/sec difference which exists between the predicted and the measured sound ,,,,,,,
speeds at atmospheric pressure. Ekman did not measure '"= =/=c pressure himself; instead he used his compressibility tu o.16 1.0 measurements to compute his operating pressures from an empirical formula which was made to agree with h 12000 $:19 0
y Amagat's data for 0*C. The error in FJrrnan's equation 1.2
{ for mean compressibility is only 0.257o, but it is suffi-i
' cient to explain the 3.0m/sec discrepacey in sound or subsequent measurements, will be available in the speed. A comparison of the sound speeds computed by future to explain this interesting behavior.
Matthews for distilled water and the sound speeds measured at NOL is shown in Fig. 6. It is seen that the VL Discussion OF ERItORS predicted speeds are remarkably accurate in spite of the complexity of the computation. In particular, it An estimate of the accuracy of the sound speed meas-l urements is obtained from a summation of the individ-ual errors. Assummg a rsadom distribution, the experi.
l M LED 6 mental error a, in sound speed that may occur for any one measurement is given by
.70 C 8 8 a,8==a af + S8at 8
+y8 ar 8 + Par8 ,
T.
ivoo -
T..ec where a, A, y, and 4 are representative constants for the i
G t.not I change in velocity with frequency, length, temperature,
$w -
. sot and pressure. */, as, ar, and er represent the standard l g f'",
i g ,,,,_ ov/ ., deviation of frequency, length, temperature, and pres-l g sure from the measured value. Thus, from Table V, the .
~ ,, g, maximum expenmental error in the measurements is U*" computed to be 0.093 m/sec. It should be pointed out
@ that the " constants" a, A, y, and 3 are not actually d'oo - constants, however, the deviation from linearity of
> these functions is small except for y. In Fig. 4 it is C seen that y varies from 4.97 m/sec/*C at 1*C to 0.00 COMPUTED FROM E0. (0
- l Eoo . coo sooo sooo Eco eh coo PRESSORE (PSt.A) ##-
Flo. 3. Velocity of sound in distined water as a function of pressure. na,_
may be noted that the present measurements are f
nearly 3.0 m/see higher than the predicted sound speeds *** -
at atmospheric pressure, as first noted by Del Grosso. N /
/
Although the second derivatives of Amagat's distilled f /
water data are unsatisfactory for the direct computa- E "- f l tion os sound speed, it is interesting to note that sound
- l speeds computed in this manner and plotted agamst E ,.co-
/ otuto warta e . . ..* c
! pressure are concave upward for Amagat's temperature range of 0 to 40*C. The curvature (concave downward)
{
5
,y'g ,,
" ~
scuo t=--,,ourutawirts o ui noted in Kuwahara's and Matthew's work must result then from the inclusion of Ekman's work. Although the majority of data referred to above pertains to sea '.ro '
f water, the same arguments hold true for distilled water /
l and can be used when speakmg of general features such as curvature. It is hoped that theoretical predictions, o i * * * '8 '
V '8 V. A. Del Grosso. Natl Acad. Sci.. Nati. Research Couscal.
l Publ. M10 (1959). Fio. 6. Conipannon of velocities predicted by
( D. J. Matthews and measured at NOL.
( .
._ _ _ ~ _ _ . _ . ___m.________..____ . _ _ _ _ _ _ _ _ _ _ _
1072 WAYNE D. WILSON
\ Tantz v.
a time delay during reflection in the NOL velocimeter 8d* " C*"** computed in this manner was found to be 0.0001 m/sec and it is considered negligible for the purpose of this
,' M 77 [ "
,. - o.2
.-o.127 m/ sc/cos work.
7Ni'mY"c*y f The remaining enors in Table V are computed di.
,,- 7.5 paa 4 0.01t m/sec/ pain rectly from the references given. The term " shear vis-cosity" refers to the viscous absorption which occurs at m/sec/*C at 74.164*C. The above error was computed the tube walls. The effect of bulk viscosity, radial and lateral heat conduction, scattering, and molecular and at a temperature where y is greatest, i.e..,at 1*C. ar, the ener in the frequency measurement, includes the chemical absorption are all absorption phenomena enor due to the accuracy of the counter and the error which are computed easily from the references cited.
l which results from the ability of the operator to set The arithmetic sum of the systematic errors is seen l coincidence. Each value for the velocity in Table I was from Table V to be +0.027.m/sec at atmospheric l obtained from the average of ten measurements of pressure and -0.013 m/sec at a pressure of 14 000 psia.
frequency at each temperature and pressure. The stand- The total error, which is the sum of the random errors ard deviation from the mean of these ten readings is and the systematic enors, is then -0.106 m/sec or 0.2 cps and it includes a 0.1 cps variation which is +0.120 m/sec depending on what pressure is cou.
characteristic of the counter.
- S Y"*"**I* "
l In addition to the random errors discussed above, systematic errors resulting from actual physical nhe- _ ,
)
i l
nonsena must be added to obtain the over-all auracy c of the measurements. Corrections may be made for It.a-eaad (time delay) fat u00 > -
Neshble E a, b systematic enors when they are known, however, since Finiu - 0.002 c, d the tables of sound speed have not been corrected for b" pulse ,",m[ybaght such errors, they are treated here like randoen errors. Radial heat conduction
- Y wh N
O ble d
d, f A complete review of systematic errors is beyond the action N ble
{fmtsmi bat
- ff~
i intended scope of this paper; a summary of these enors is given however in Table VI for reference. The enors Chemucal Depamon absorpuna N ble g
! l l N ble h in Table VI have been computed to the first three sig- !
ninant figures and errors which are less than 0.001
- 5,5;s.=n pa,,s gg;g;g g psg, m/sec are considered as negligible in this report. ,
ne pressure differential error is an enor which re- gm ,=8==.=,".644.s.Frr.r.w xw mu.u a.m. wn.,
= A 4 :=+ s = vert. iesu).
sults from the force required to compress the bellows M 5 d** # ,*"r=IJ D ' T ""'
of the velocimeter. This force causes the pressure inside tM ielema. ra , ./ s v, mJ".c". uai *f.d.J" c e.2f.".'.'r".*1.is-the velocimeter to be less than the pressure outside j l where the pressure is measured. The error due to the
!Ir;,M.uggwg a sgig , gg rt. iesu.
small pressure differential listed in Table V is the i ma==== error expected. This error will decrease 10 ap.
000, sidered. The over-all accuracy is then at least 1 pa i
Prossmately linearly to zero as the pressure goes t atmospheric pressure. It is also conceivable that this VIL ACENOWI.EDGMENTS presure difference may cause a deflection in the crystal l The author is deeply indebted to Mr. Dudley Taylor transducers in the NOL velocimeter. If this should for the design and construction of the velocimeter, for l
occur, the m = mum error in sound speed produced by the pressure vessel, and for the frequent consultation on the dastortion would be -0.030 m/sec at 14 000 psia the numerous problems encountered in this work.
and would decrease linearly to zero as the pressure is Equally important has been the work of Mr. Walter made to approach its atmospheric value. The third Madigosky who contributed much thought and effort enor listed in Table VI is due to the time delay that . to the choice and assembly of the necessary instrumen-l occurs during reflection of the sound wave at the trans- tation for the measurement of sound velocities. The ducers. This additional time delay has been computed author would also like to express L'; gratitude to the by treating the transducer as a damped mechanical IBM computer staff at NOL for theu participation in system which responds to a transient force. Only the the derivation of the velocity equations expressed first half-cycle of the incident wave train was con- herein, and to Dr. T. A. Litovitz, Dr. H. E. Ellingson, sidered in this analysis since this is the portion used to and Mr. A. T. Jaques for their frequent aid and en-measure sound speeds. The error in sound speed due to couragement of this work.
I D
l
_ . - ~ _ _ . . . _ - - - _, - _ _ , - - ,. _- _
m _
THE JOURNAL. OF THE ACOUsTICAt. SOCIETY oF AMERICA VOLUME 31. NUMsEn 3 WCUST.1939 Resonance Absorption and Molecular Crystals. IL Benzenet LaowAan LisosaafANN Unmesity of Cditornia, La Me. Cdiformin (Received March 24,1959) within each molecule. Thane two vibrational medes ra ons cas overlap lands to lengthy retssation times rnanifested as unusually ,
hieh acoustic absorpt sonate ** This neonance nomenon termed for growing single bensme crystals of average linear ea develop requency 10 r ,
d dimension absorption es:essively high in single(10*
absorption bensene hieher thancrystals in a is found to b' O.24 cm-'t at 6.4 ac the value is 00 cm-'. i is resonance absorption is predicted to be the dommant .
n which absorptio INTRODUCTION absorption in the solid state. One of these, benzene, A thermal oscillation: those in which each for was selected moleculeMOLECULAR initial study because of the wide crystal vibrates as a whole about its lattice position, termed variety of thermodynamic data availab the acoustical branch, and the internal vibrations of compound. Although bensene is a liquid at
' the atoms comprising a molecule, termed the optical temperature it has a relatively high melting point branch. In many crystals these two vibrational modes(5.5'C) which makes its study in the solid state overlap in frequency, leading to resonance. Possible without unusual techniques. However, it is Previous work,' hereafter referred to by the designa. ".ecessary for acoustic observations to be made on a tion I, has shown that resonance can result in unusually smgle crystal rather than on the polycrystalline state, high acoustic absorption. High absorption results from in order to eliminate contributions to absorption froen the relatively slow transfer or exchange of energy friction and scattering at crystal boundaries, fractures, and at other imperfections. For this reason a large single between lattice and internal vibrations. Just as inof bensene was grown for the purpose of the
{ weakly coupled mechanically resonant systems, the C'Y5t"I.
tasasfer energy at resonance is large, but the rate of acoustic observations. The following sections describe the method of preparation of the crystal and observa.
transfer is slow, particularly close to resonance. The tions of the acoustic absorption.
phenomenon is some respects resembles the familiar l relaxation absorption observed in gases and liquids, but the latter arises from transfer of energy by collision, GROWTH Olr MONOCRYSTALLINE BENZENE whereas the present phenomenon requires near fre. As in the case of nearly all organic compounds, quency coincidence of two vibrational states; hence the molecular binding forces in benzene are relativ term, resemence a&sorpties. It should be emphasised (its binding forces are largely van der Waals that this resonance phenomenon is not associated with Consequently crystalline bensene is a fragile substance acoustical frequencies but rather with the extremely incapable of supporting severe thermal stresses. The high frequency thermally excited vibrational modes conventional technique for crystal growth in which within the crystal, heat flows through the external crystal surface intro-It was shown in I that the rate with which energyfor duces far too many stresses and could not be utilized benzene.
oscillates between the two vibrational syrems deter.
mines the acoustical absorption; a low transfer fre. The schematic diagram given in Fig.1 illustrates the quency leads to large acoustic absorption. Stated in method whereby unsupported thermal strains were another manner, whenever the oscillator coupling is avoided in crystal growth. Instead of the usua small, or the intennolecular binding forces weak, of crystallization from the liquid, whereby heat absorption will be high Conversely,in highly absorbing extracted from the external surfaces, heat is e crystals the Lennard-Jones molecular constants, e and from within. The coldest exposed region is the re , will be found to be small and the intermolecular heavy copper rod on which the seed is placed. He spacing large, extenor growing sudace is always warmer than the Tables of the Lennard-Jones constants suggest that central region and thermal stresses are compressiv many organic compounds should exhibit resonance rather than in tension. In practice the copper tip was attached directly to the refrigeration coils and operated t hismentwork received support from the Bureau af Ships. Navy in the vicimty of 0*C. The air temperature in the n from the Scnops Institution or refrigerator was accurately controlled by means of
- L. Liebermann, Phys. Rev. !!3,1052 (1959). heaters and thermostats at a constant temperature
% m the vicinity of 3 C. In addition a small amount of 1073
. - ~ .. - - .. . - , - . - .~ . - - ~ . - . -. .- . . - - - - . - -.- - ----.
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ALTsc LAmstwo ConroaAT!oN, Anaheim. California l speakere. Ampaisere. Mawooheems. Trametermare Aurex ConroaAT!ow. Redwood City. California Masusue Teou asserders for amesa, ledemarini, and Miksary Purposes Anaestaowo CoaK CourAwT, Lancaster, Pennsylvania A ommaar uma er a-w caiumas rar Name and sedesary AUTouAT EtscTasc CourAwT, Chicago. Illinois sasmen ad teammanciarwe et Teessamme sceamses Bau. s Howatt. CourAwT Chicago. Illinois Mesmosas Tase ascerdsee ws LamonATonias. Iwc., New York. New York Bau.
mes noTsLarnosimeases med os for ime Sea svanem BsLTows MsAmtwo Ato CourAwT, Chicago Illinois Dessemars and Mamadacterare of Hannae Aads and Andassneter.
Boorns Sopwontvs CourAwT. La Anples 28. California Very High Amputade samed and h=w Vibrosian semusesse BcLT BamANsE AwD NawuAw, Cambridge, Massachusetts r -im Assessnes Benosas.MANwtwo CourW". Libertyville, Illinois sannesen, snaisen. Dennese, oss ama Air uma. Assast6.seeths CArtico Rsconos, Inc., Hollywood, California ressmaraoh am mes j
Tas CsLotax CoaroaAttow. Chicago, Illinois .
A esmeiste uma of arehtesseural annusasemi manartate C. G. Coww. Ltn., Elkhart. Indiana j Mesman and summisse t_
CunTsse.Wasout Con.roaAnow, Quehanna, Pennsylvania assare and Fredess os einement DscronaArs PacoocTs,Inc 95-25149th Street, Jasmasca 35, New York Hamress Alda,immer.sese Telephase Syseensw Fire Aisress g
DooaLas AnacaAr7 courant, Inc., Santa Monica, California Anwest Maassasseries DeKAws CoaronATlow. St. Charles. Illinois Teos Ameerdern, somed sude.rge Prh Commel seemd Sr nema. !--*-
Eno CommmTsow, College Point. New York Transdesers. Uhrmasmic novuse. Samar sempreset H. A. Ear Acoust: CAL courant, Cleveland, Ohio Aressemarmi ne Eastasus and Compusene GawsaAL ELacTasc CourAwT, Applaance and Television Receiver Division. Louisville 1. Kentucky GawsAL ELactmic CourAwT, Schenectady 5 New York GswsmAL RAoso CoasrawT, West Concord, Man chusetta asund vinnesess. and cement sasswome Lammeneery tasarummens GawsaAL Soown Coorract IncoaroaATsD. IAe. Angeles 45, California sumsmen, - w remsen,Asamusasammustand pe esa, mens Gastrw BAcow MawayActuanwo CourAwT, Kansas City, Missouri Anaessmerna and seemserina *- pmdeses HAssasown Omoam CourAwT Chicago, Illinois sammie cwoses, and samarians useums !-
tweestalAL ]temmaarw PacoccTs. !*: Franklin Park. Illinois os.misememmi and Menesessenes sesmupe; aise Amet Fredmets twTsawATlowAL BUstwaSS MACstwES CoaronATion, Poughkeepene. New York
- --erersammes u- -
tsyssw MAwarAcTutano CoastAwT, Chicago, Illinois 1 - - _ sestesases. Asmumense Any person or corporation contributing One-Hundred Dollars ($100.00) or more annually may be elected a Mesmber of the Acouencal Society and will rec 6e one subscription to the journal for the year and a yently mem certi6cate sinnsable for framing. Application for reembership may be made to Secretary Wallace Waterfa!!.
AUoDST,18se TNE JoCENAL or THE ACOUSTICAL soc 1ETT oF AMERICA O
pagT. J. APPL PHYS. 1%7. VOt. 18. PRINTED IN GREAT BRTTAIN q
V Pressure dependence of the velocity of sound in water as a function of temperature A. J. BARLOW and E. YAZGAN Department of Electncal Engmeenng, University of Glasgow MS recesved :Sch Jane 1966, m rensedform 18th November 1966 Abstract.
Measurements of the velocity of sound in doubly distilled water have been made at pressures up to 11600 lb in-8 in the temperature range 1644*c. The basic expenmental techmque and the theory of measurement have been described in detail m a previous paper by Barlow and Yazgan. "Ihe results are believed to be accurate to 74*c. withm =0 30 m sec-1 at 16*c. the error decreasms to =0 20 m sec-1 at about A polynomial has been fitted to the data to permit calculation of the velocity at any temperature and pressure in the range investigated. The results at lush ptissure are generally in agreement with those obtained by Wilson, although substantial differences at atmosphenc and low pressures indicate some systematic error in Wilson's results.
The factors involved in making definitive measuremems of higher accuracy are discussed.
- 1. Introduction Several measurements of the variation of the velocity of sound in water as a function of pressure and temperature have been made in recent years. Up to 1959 the aa:uracy of such measurements was rather limited. Tew investigators claiming a maxtmum error of n)
(
v less than i 01 % (Holton 1951, Smith and Lawson 1954, Litovitz and Carnevale 1955.
Tait 1957). Comparison of the values obtained at the same temperatures and pressures shows discrepancies exceeding this limit. In order to obtain more reliable values, Wilson (1959) carried out an extensive series of measurements of the velocity of sound in distilled water at pressures up to 14 000lbin-8 in the temperature range 0-100*c. A maxtmum error of 0 01 % is claimed for these results.
The acoustic system used by Wilson (1959) was simdar to that developed by Greenspan and Tschiegg (1957) and used for the determination of the velocity of sound in water as a function of temperature at atmospheric pressure. Essentially their method involved a measurement of the transit time of a short transient sound pulse through a known liquid path length, the pulse being generated by shock excitation of a piezoelectric transducer.
Recent measurements by Barlow and Yazgan (1966) have shown that although the variation of velocity with temperature found by Greenspan and Tschiegg (1957) is sub-stantially correct, their absolute values are high by approximately 0 40 m sec-1 The technique developed by Larlow and Yazgan (1966) is based upon measurement of the total phase shift experienced by a modulated high-frequency pulse propagated through a known liquid path. This method is capable of high accuracy and. under suitable conditions.
absolute accuracies to within = 0 003% are attainable. The results obtained over the temperature range 23-80*c are in agreement with those of McSkimm (1%5), !!gunas.
Kubilyunene and Yapertas (1964) and others. In particular, the value of 1496 58 = 0 04 m sec-a obtamed at 25 000*c is in close agreement with the value of 1496 55 m sec-1 recently found by Gucker. Chernick and Roy-Chowdhury (1966), usmg a different expen-mental technique of comparable accuracy.
The values of velocity obtained at atmosphenc pressure by Wilson (1959) are consistently higner than those found by Barlow and Yazgan
- 1966). The difference mereases from a value of 0 34 m sec-a at .tbout 74*c. where the velocity of sound in water passes througn a maximum. to approximately Om5 m see-t at 25 000*c. For companson. the aosolute accuracy claimed by Wilson i1959) corresponds to a maximum error of 015 m sec i
- 3 M5
%.)
t
l 646 A. J. Barlow and E. Ya:gan In view of the evidence for a systematic error in the results given by Wilson (1959),
possibly inherent in the type of acoustic system employed, there is a need for a defmitive series of measurements of the velocity of sound in water over wide ranges of temperature and pressure.
As a step towards this objective, measurements have been made over the temperature range 16-94*c at pressures from atmospheric to 11000 lb in-2
- 2. Experunestal 2.1. Acoustic system and velocity measurement The fixed path acoustic system used to obtain the results given in 13 is similar to that developed by McSkimin (1957). The electronic system and method of velocity measure.
ment are considerably different, and have been desertbed in detail in a previous publication (Barlow and Yazgan 1966). A diagram of the acoustic system is given in the figure.
' -' Electrical
' connec Nms
/
k '
j i
i /
l E p ,
hf % ' Secamq scres
', I s ; l""r-- X-cut esc +tt crystal h - r -Fused quarts buHer rod
, -- --0-req seal Q ***
{ > ,
l l WFesed quarts reg spacer fO j l
1,- *Termmatmg red V / l 1-;'-- 5prmg
./ -
/ /
Sellowl
, /
/ #
/ l
, ;r-0-tmq sesi
/ / Ice
/ ', m
/', , ,-
Acoustic system for measurement of velocity under high pressure.
The length of the liquid path is defined by a fused quartz ring spacer. The end surfaces of the buffer rod are optically flat to 0 1 pm and parallel to 5 seconds of angle. The faces of the ring spacer are similarly optically flat and parallel, and one end of the terminating rod is also optically flat. By wringing the cylinders to the faces of the ring spacer, a known and reproducible separation of the cylinders is obtained. Small radial grooves on opposite sides of the spacer allow the liquid to fill the space between the faces of the fused quartz rods. The effective separation of the two quartz cylinders was determined by making an extensive series of measurements of the velocity of sound in water at atmospheric pressure and comparing the results obtained with those using precision gauge blocks in place of the ring spacer (Barlow and Yazgan 1966). Thus, although the linuted space in the high-pressure vessel precluded the direct use of gauge blocks to define the liquid path, the effecuve lergth of the ring spacer at atmospheric pressure was determined by ref erence to the previous measurements. By this method the separation was found to be 0 304 588 in., givtag an acoustic path length of 1 547 307 cm. This value is in excellent agreement with the results of a senes of measurements which have been made by the Metrology Division of the
i l- Pressure dependence of tlm ~ocsty of soundin water ar afunction of temperature 647
[
National Engineering I.aboratory, of the thickness of the spacer at several points. These measurements gave an average thickness of 0 304 $80 ::: 0 000010in.
As shown in the ftsure, the acoustic system was mounted vertically in a holder inside the Pressure vessel. A light spring was used to apply a slight axial force to the te. inating
. rod, chie6y to prevent damage should the parts of the acoustic system be:ome separated.
1.
This spring was not such as to cause appreciable compression of the fused quartz ring i spacer. The water sample was separated from the pressure transmitting Huid by means of o'. rings, and a bellows allowed compression of the sample.
2.2. High-pressure apparatus and temperature mearurement A conventional arrangement of the high-pressure system was employed. The pressure was generated by a hand pump and morutored by a Bourdon gauge. The pressure vessel had an internal working space it in. diameter by 10 in. long, which vas suf5cient to cor tain the acoustic system and a special thermocouple. Pressure measurements were made by means of a dead-weight tester (Barnet instruments Ltd. type 4540), for which a maaimum error of s3 parts in 104 is claimed. This instrument was correctly calibrated for the local gravitational factor of 981 55 cm sec-2, and the readings in bars were converted to Ib in-using the relation I bar = 14 504lbin-8 A silicone liquid was used as the pressure transmitting fluid.
The pressure vessel was fitted with a heating jacket, and the temperature was stabilized by a sensitive controller based upon a design by Tempest (1963). A thermistor in the inner shell of the heating jacket was used as the sensing element.
The temperature in the pressure vessel was determined by the use of an iron-constantan ,
thermocouple arranged so that the thermocouple junction was as near as possible to the
! fused quartz ring spacer, although outside the water sample. This thermocouple was calibrated in the open pressure vessel directly against a platinum resistance thermometer cert 8ed by the National Physical Laboratory. Measurements were made at a number of points in the rar.ge 20-100*c. Checks were made of the temperature variation with thermocouple position inside the vessel and it was found that the variations were insigni-Scant. It is estimated that the overall accuracy of temperature measurement was such that a maximum error of :i- 0 03 desc was possible. For measurements made under pressure, the rendangs of the potentiometer used to determine the thermocouple e.m.f. were corrected for the pressure dependence of the e.m.f. The results of Bridgman (1918) for an iron-constantan thermocouple were used to make these corrections: in general the corrections were small or insignincant.
! 2.3. Watersample Doubly distilled water was used throughout. This degree of purification was considered adequate in view of the negligible effect of small quantities of impurities on velocity (Weissier and Del Grosso 1951, Del Grosso. Smura and Fougere 1954). No attempt was made to free the water of dissolved air, since the effect on velocity is probably less than I part in 106 at atmospheric pressure (Greenspan and Tschiegg 1956). However, care was taken to prevent the inclusion of air bubbles when filling the sample container, so that the sample measured was saturated with air at atmospheric pressure.
2.4. Experimentalprocedure
' Measurements were first made of the velocity of sound in water at atmosphene pressure and a temperature of about 20*c, with the sample in the pressure vessel and using the associated temperature rnessurement and control apparatus. The results at nominal operating frequencies of 10 and 30 Mets were in agreement to within 0 % m sec-8. after applying a correction for the effects of diffraction. The value at 30 Mcis was found to be only 0 02 m sec-1 less than the value obtained by extrapolation of the results of Barlow and Yazgan (1966) which were obtained over the temperature range 23-80*c. At about l '
I i
i l
l
)
1
(
648 A. J. Barlow and E. Yazgan 20*c an error of 0 03 degc corresponds to an error in velocity of about 010 m see-i.
l the estimated limit of temperature error given in i 2.2 is therefore substantiated.
i A series of velocity measurements was then obtained at a temperature of about 16 6 e over the pressure range from atmospheric to 1000 bars, using a nominal operatmg frequertcy of 30 Mc/s.
pressures.
Measurements were made at intervals of 100 bars for increasing and decreasing Although pressure changes were made very slowly, about one hour was required for the restoration of thermal equilibrium after each pressure change. Slight pressure l
readjustments were made during this time to confine readings to exact 100 bar intervals and to allow for the very slight leakage in the dead-weight tester. This leakage was greater at the higher pressures and some instability at 900 and 1000 bars was found. Accoidingly, the pressure range was restricted to 800 bars. Only the results of a series on' measurements in which velocity values forincreasing and decreasing pressures agreed to within 0 20 m sec-t were regarded as acceptable, and the average value was taken at each pressure.
For temperatures above about 30*c it was thought undesirable to make measurements at atmospheric pressure since the expansion of the enclosed water sample could distort the bellows and a slight excess pressure may have given unreliable values of velocity. A pressure of 100 bars was therefore applied before increasing the temperature above about 30*c and all initial readings were obtained at this pressure.
- 3. Resmits The experunental results are given in table 1. Except for the six values given for tem- I perature:; above about 30*c at atmospheric pressure, each value of velocity is the average of readings taken with increasing and decreasing pressure obtained at a nominal frequency of 30 Mc/s.
A s'nali correction, equivalent to a maxunum of 0 05 m sec-1, has been applied to accourit for the change in length of the fused quartz ring spacer with temperature. Since
[ the spacer is compressed by the hydrostatic pressure, a correction amounting to a maxsmum
) of I 24 m sec-1 at 800 bars has also been applied to reduce the apparent velocity to the
(/ true value. This correction has been based upon a value of 5 35 x 108lbin-8 for the bulk modulus of fused quartz obtamed from published clastic constants (American Institute of Physics Handbook 1957) and from data given by McSkimin (1957). This value has i
been taken to apply over the temperature and pressure range of measurement. the amount l
of the correction is correct to better than i2% over the range (McSkimin 1957).
A correction of 0 02 msee-2 for diffraction efects has also been applied to the data, following the theoretical results of Bass and Williams (quoted by McSkimin 190), which have been confirmed expenmentally by Barlow and Yazgan (1966). Errors arising from other sources, for example the diferential pressure across the bellows, are negligible and .
corrections are therefore unnecessary. l
- 4. Analysis of experunestal results Following the procedure adopted by Wilson (1959) an equation of the form V = ao + atT - asT -- asT3 :- a<T* -- asTsm sec-l m where at = bro - be P - be:P8 - br:P3 - br<P4 (2) has been fitted to the results. The coefficients of equation (2) are given in table 2. In these equations T is the temperature in 'c and B is the absolute pressure in umts of 1081b in-8 The coefficients are valid over the range of measurement 15-95'c. and from atmospheric pressure to just over 108 lb in-8 As a check on the fitting of these equations, recalculated values of the velocity at the l temperatures and pressures of measurement have been obtained and compared with the j
original data. The greatest deviation was found to be 019 m sec-8 with an average or, 0 065 m sec-l. the deviations being randomly distnbuted throughout the temperature and pressure range.
lb lV
O O O 4
A .
k
'Iable 1. Emperionesotal values of the velocity of sound (as sec 8)in weser as a funcelen of tesaperatiere and pressure Tempes ature (v) 16 565 f r 30 600 39 930 47 990 60 590 71 350 78 850 93-370 lascanne (Ib in s) h g
R& 7 1471 19 1510 58 1528 66 '
1540 16 1551 24 1554 91 1554 64 1548 26 1450 4 1487 79 1527 81 1546 04 1557-93 1569 83 1574 02 1574-27 1569 01 2900 8 1504 25 1544 52 1563 32 1575 42 1587 92 1592 88 1593 45 1589 12 7 4351 2 1520 73 1561-58 1580 60 1593 05 1605 83 1611 44 1612-41 1609 20 2 5801 6 1537 78 1578 37 1597 51 1610 07 1623 37 1629 54 7252 0 1595 30 1631 03 1628 23 $ !
8702 4 1554 64 1578 82 1611 78 1614 61 1631 22 1627 21 1640 87 1647 08 1648 99 1647 18 g '
1644 31 1657 96 1664 66 1666 75 1665 92 10152 8 1589-13 1628-82 1647 94 1660 86 1675-03 1681 99 1684 40 1683-93 18603 2 1605 82 1645 35 1664-43 1677 46 1691-75 1699 06 1701 55 1702 40 5
lable 2. Cecebicients of the essentions an - bee i bnP i bnP8 I bsara g 3,, rig 0 1401 Y$8 b.e I83 73652 b.s
-149 69035 bas boa 20 51695 --31 83572 bne l
a i 1 5 051718 14 325934 00579 1 3 787598 II 452633 'n-2 5 848526 -10 8 -2 029127 x 10 8 l-5 478028x 10 8 --3 373606x 10 8 17-830629x 10 8 $
3 13 381084 s10 l 4 493318 x 10 a 1 290872 x 10
- I 9 460639 x 10 a g.245880>:10 8 5 4 1 484859x10 * - 4 498863 x 10
- I I 357265x to * -1090535 x to a g 9g432y ,.30 s 13 091069410
- I I 674%2 x 10 ? 5 229535x 10 ?
5 I 4 441468 x 10 ' 9 317469sto
- b] ,
i l' a. I a T I asT8 I a:Ta I n T4 I asT*m sec- 8, where Tis in 'c arni P in units of 108 lb in 8 abwfuse.
f '
h ii o I
650 .L J. Barlow and E. Ya:gan
/~h
- 5. Desenssaos The main errors in the results given anse from the uncertainties in absolute pressure and temperature measursment. The possible error of 0 03 desc in temperature measure.
ment corresponds to an error of =0 10 msec-1 at about 16*c, decreasing to zero at about s 74*c, where the velocity passes through a maximum. Although the dead-weight tester used is capable of absolute pressure determination to i3 parts in 104, a realistic estimate of the precision obtained indicates that it is reasonable to allow limits of i10lb in-2 on pressure readings throughout the range. This uncertainty arises from the difficulty found in rnaintaining constancy of pressure at de limit of sensitivity of the instrument. The i absolute pressure is then accurate to 13 lb in-8 overall, corresponding to a possible error in velocity of =013 m sec-1 As desenbed in the previous account of the experimental technique for velocity measure-i
" ment (Barlow and Yazgan 1966), random errors in velocity ari:i;ig from the electrical measurements of 0 02 m sec-L. are small and have a maximum of 60 04 m sec-1 with a standard deviation
- The sum of the random errors is therefore 0 24 m sec-1 at room temperature, decreasing to =0 14 m sec-1 at about 74*c. Examination of the expenmental data shows that the values obtained deviate from smooth curves by random amoums which are less than these estimates. Except for a possible uncertamty of about 1 part in 105in the length of the liquid path defmed by the fused quartz ring spacer and possibly slight errors in the variation of this length with presmre, systematic errors are, by com-parison, negligible. The results given are therefore estimated to be accurate to within 0 30 m sec-1 around 15'c and to within iO 20 m sec-1 around 74*c. A F cw8on of the results with those obtained by Wilson (1959) shows significant differer
. _ te a values obtamed at atmospheric pressure, and differences in the variation with pressure at constant temperature. At atmospheric pressure. the present results are some 0 65 m sec-1 lower around 20*c and 0 34 msec-8 around 70*c. These differences become gradually less with increasing pressund are change sign at about 10 000 lb in-8 at 20*c and 5000 lb in-8 A)
("
at 90*c. 'Ibus, although the values at atmospheric pressure indicate a systematic error in Wilson's results, over most of the pressure range there is agreement within the combined expenmental error limits between the two sets of values. It is possible that the systematic error is reduced by increase of temperature and pressure, or that the differences are reduced
- by small unsuspected temperature or pressure dependent errors in either the present results or those of Wilson.
1 i
In order to obtain definitive values of the velocity of sound in water as a function of
- pressure and temperature, significantly better than the ex2stmg data, further experimental work is required. Absolute velocity measurements accurate to about 3 parts in 10s are now possible without undue difficulty. The reduction of errors arising from inaccuracies in pressure and temperature measurement to this level or less would involve considerable i
expenmental problems. It is preferable to define the liquid path by precision gauge blocks; the resulting increase in the diameter of the acoustic system would entail a larger
' pressure vessel Absolute measurement and stabilization of the temperature of the water sarnple to 60 001 desc is desirable, and can only be achieved by immersion of the vessel i
in a large constant temperature bath and by the use of a platinum resistance thermometer 4
i in conjunction with a Smith bridge or umHar instrument. The greatest problem anses m absolute pressure measurement. Direct use of a dead weight tester is undesirable since.
l although the time required for the measurement of velocity is only a few minutes, the slight leakage in this time may give some uncertamty in pressure readings. A sensitive secondary i
gauge is preferable, but reduction of the absolute error in pressure to a maximum of I or 21 bin-2 at about 104 tb in-8is extremely difficult and is close to the limit attainable at the present stage of development of high pressure measurement.
. A--
Thanks are due to Professor J. Lamb for his encouragement and help in this work . tad for the provision of facilities. The work was supported by a contract with the Nanonal Engmeering I.aboratory, Mimstry of Technology. The authors are grateful to Mr. A. T. J.
1 Hayward and the Metrology Division of the Laboratory for their kind assistance.
3;
Pressure dependence of the t elocity ofsound in water as a functson of temperature 6$I p)
(
Q-References BAaLoW. A. l.. .Lnd YAZGAc.. E.,1966. Brn. /. 40p1. Phvs. 17. 807-19.
annoouAN P. W., l918. Proc. Amer. Acad. Arts Sea.. 53, 269-186.
Det Gaosso. V. A.. SuURA. E. J., and Foucrat. P. F.,1954. U.S. Naval Res. Lab. Rep., No. 4439.
. GassNEPAN. M., and TSCHisOC C. E.,1956.1. Acoust. Soc. Amer., 24, 501.
- 1957.1. Res. Nat. Bar. Stand.. 59, 249-54: Rev. Sci, instrum.. 28,897-901.
GucKsa. F.T., CusRNICK.C. L. and Rov-CHOWDMURY. P.,1966. Proc. Nat. 55.12-19. Acad. Sci..
HoLioN. G.,1951. /. Appl. Phys.. 22.1407-13.
Ito vNAs V., K va:
LyuNaNs. O., and YArsmTAs, A. 1964. Soviet Phys.-Aroust. 10. 44-8.
1.rrovrtz. T. A., and CAaNEVALE. E. H.,1955./. Appl. Phys., 26.816-20.
Mc5aruN H. J.,1957 J. Acoust. Soc. Amer. 29. I185-92.
- 1%), /. Acoust. Soc. Amer. 33. 539.
- l%$. J. Acoust. Soc. Amer.. 37.325-8. 1 Surrn. A. H., and LAwmN. A. W. 1954. J. Chem. Phys.. 22, 351-9. l Tarr, R. I.,1957. Acustica. 7. 193-200. i TsWPtsT. W.,1963. Beetron. Entar. 35.814-6. 1 Wmar sa A., and DrL Gnosso. V. A. 1951.1. Acoust. Soc. Amer., 23. 219-23. !
Wrtsow. W. D. 1959.1. Acoust. Soc. Amer.. 31. 1067-72. 1 l
1
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J DalT.J. W R PHYS.,I M.Vol 17 O Phase change method for the measurement of M ultrasonic wave velocity and a determination of j the speed of sound in water
- A. J. BARLOW and E. YAZGAN Department of Electncal Engineenng. University of Glasgow MS. recessed 29th Vovember 1965. m restadform iSth February 1966
}
Abstreet. A description is given of a technique for measunng the ultrasons wave j velocity in liquids, based upon the measurement of the total phase shtft through a !
liquid path at fregi- in the region of 10 Mets. A timed-path scousue system is j employed and the method is suitable for use over wide ranges of temperature and hydrostats pressure
' The phase diference between a modulated r.f. pulse propagated through the known liquid path and the incident pulse rs6ected from a solid-liquid interface is desemuned by cancelling each pulse separately agamst a conunuous-wave signal adjustable m
]
- phase and amplitude. From two such measurements at slightly diferent frequencies the total phase stuft in the liquid rnay be emannaeare i
The rachnique is entsahia of very high accuracy and under suitable conditions an
' absolute accuracy to better than 3 parts in 10' in velocity is obtamable.
l Measurements of the velocity ofsound in water have been rnade over the temperature 1 range 23-30*c and the rueults are presented as a Afth<iegree polynomial. A value 1 of 1496 58 ::: 0 04 masc-* at 25400*c is obtained.
4
, 1. Imeredsettes l l
i Any study of experimental methods for the determmation of the velocity of sound in l liquids leads inervitably to a comparison of the values obta ned for water in view of the ;
!p ~
many measurements of this basic reference value made during the past thirty years. A i summary of results reported up to 1954 is given by Del Grosso. Smura and Fougere (1954).
The results show considerable scatter, and more recent measurements made by means of experimental techniques apparently capable of high aczuracy have not fully resolved the i discrepancies. The present situation is shown in table 1. Only those results are given j
for which an accuracy to better than iO03% is claimed. Four of these values are in L.,
Table 1. Vaisse of the veisemy of seed la water at 2548*C h Reference 1
Expenmental technique Velocity Limit of j (m seed) error
! claimed (m sec-')
Barthel and Nolle (1952) Double crystalinterferometer 5-25 Mc.s. 1496 t =0 20 vanable path of a few cm Del Grosso er at (1954) Single crystalinterferometer 1 Mets. 1497 41: =0 05 vanable path of a few cm Greenspan and Tschiogg (1957) Tirne delay, daad path 20 cm 1497 00 =0 05 Brooks (1960) Time delay, vanable path 1-2 m 14% !' =034 Neubauer and Dragonettei1964) Time delay, diferential path about I m I496 ,0 :0 20 Ilgunas er a4. Sinste crystal mterferometer.1-12 Mcis. 1496 594 =0 t 5 vanable path of a few em McSkimm i1965) Modulated pulse cancellation. 90 Me.s. 1496 65 2010 rixed path ofless than I cm
- Extrapolated from 24 76"c: extrapolated from 20M*c: ) extrapolated from 1710'c usms data of Greenspan .md Tscruess e 1957) m each case.
39 107
(
t
. m._ __ _ _ _ _ _ _ . .- _ _ _ _ _ _.... _. ._.__ _ _ . . _ ._ _ _ _ _ _ _ _ _ _ _ _
k 808 A. J. Barlow and E. Yargan j
- \ agreement within the limits of stated error, those of Brooks (1960). Neubauer and Dragon-i ette (1964). ligunas, Kubilyunene and Yapertas (1964) and McSkimin (1%5). Two other results, for which the highest accuracies are claimed, those of Del Grosso et al. (1954) and Greenspan and Tschiogg (1957) diser considerably.
Several factors may be readily excluded as possible reasons for these diferences. The 4 variation of velocity with temperature around 25'c is 2 7 msec-2 desc-$ (Greenspan and l Tschiegg 1957). thus the variations in the values are too large to be explicable as temper-ature errors.
l Deviations from absolute purity of the samples of water used are unlikely to be sources of substantial errors.
j Dissolved air has been found (Greenspan and Tschiegg 1956) to increase the velocity of sound in water by less than a few parts per million. Small quantities of other impurities have been shown to have negligible esect (Del Grosso et al.
1954. Weissler and Del Grosso 1951).
k On the evidence available it therefore seems probable that certain experimental techniques.
i including those of Del Grosso et al. (1954) and Greenspan and Tschiegg (1957), are not
- i. suitable for absolute measurements of high precision. Systems involymg steady state 1 sinusoidal wave propagation are preferable to those involving the propagation of transient waveforms, or step functions, over distances appreciably less than 1 metre. Error estima-l j tion in the latter systems is dificult since pulses may be distorted by resonances m tra_.s-
' ducers and by diferent absorptions applying to each Fourier component of the transient waveforms.
I In view of the importance of difraction of the acoustic wave on observed velocities. the j frequency of operation and dimensions of the acoustic system should be so chosen that difraction efects are small or negligible. Calculations of difraction corrections have j been given by McSkimin (1960). Bass and Williams (reported by McSkimin 1%1) and Del Grosso (1964). Furthermore. experimental techniques requiring only small quantities
' of liquid are preferable sicce temperature stabilization is simpli6ed and measurements under high hydrostatic pressure are possible. The choice of a Axed-path acoustic system i
i . reduces the problems of mechanscal alignment and further facilitates the study of velocity as a function of pressure.
i ) A Axed-path acoustic system based on the design of Schulz (1955), as developed by i
McSkimia (1957), futils the foregoing conditions and has been taken as the basis of the i
i experimental technique used in the present work. However, a new method of measurement based upon a deternunation of the total phase shift in the liquid path has been devised, j
nis method gives a diferential accuracy comparable with that of the ' sing around* tech-i nique used by Greenspan and Tschiegg (1957) together with a high absolute accuracy.
i De method uses a continuous sinusoidal waveform gated to provide a pulse of r.f.
oscillations, which is propagated as an acoustic wave through the liquid path. The pulse l j
duration is sufRcient for steady-state conditions to be attained after the decay of the initial i transients.
i The time taken for the acoustic pulse to travel through the liquid path is determined by phase comparison with the original continuous waveform. Essentially, i the method combines the high resolution and accuracy of a conunuous-wave interference j
- measurement with the advantages of a pulse propagation technique. A detailed descripuon of the system is given in the following section.
! i
- 2. Exper6 mental system l 2.1. Mosle of operation I
i A schematsc diagram of the experimental system is given in figure 1. A continuous wave i
' signal from the crystal-controlled oscillator ai is passed through a bufer ampli6er b to a diode gating circuit c. The gate is opened by a pulse of a few microseconds duration to
! 1 produce a short wavetrain which. after further amplification (d), is used to excite the X cut i quartz crystal transducer of the acoustic system. Longitudinal waves generated by the transducer propagate in the fused quartz rod and are partly reflecter. at the quartz-liquid
) interface Part of the incident wave propagates through the liquid and. after rerlection from the boundary between the liquid and the terminatmg fused quartz rod. follows the
i Sound relocary m water by phase measurement techmque i 809 ACQUlf tC
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f"' I Oesialensees en I
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Ceesisi sense, ussenisu iengins b b usies C sense.
asesesme teges gif tettog tp 100 sa diHe'est 67 10 se Figure!. Schematic diagram of expenmental system.
I first re6ected wave in re-exciting the transducer. The output from the acoustic system is passed through a buKer ampli6er e and into the receiver f. The received pulse train is
- displayed on the oscilloscope. Apart from the transmitter pulse, the display shows two main pulses, the first from the fused quartz-liquid interface and the second resulting from
! one double transit of the liquid path by the sound wave. The total phase diference
- between the high-frequency content of these two pulses is a function of the velocity of sound in the liquid. In addition, the display will contain subsequent pulses which have made further transits of the liquid path or the buKer rod. In the present system these pulses are irrelevant.
O The rememmqr part of the system provides a reference signal for measuring the phase diference due to the liquid path. A signal from the oscillator a spasses through a bufer ampliner g to a simple uncalibrated phase shifting network h. This is followed by a precision adjustable delay line j capable of providing a known and continuously variable phase shift. Accurately matched source and load impedances are used to minimize standing waves on the delay line. The output from the line is further amplined (!). con-trolled in amplitude by a piston attenuator m. and passed through a bufer amplifier n into the receiver.
2.2. Measurementprocedure The phase diference between the waveform of the pulse reflected from the interface and that which has made one double transit of the liquid path is determined by cancelling each separately against the reference signal. Initially, the uncalibrated phase shifter and the attenuator are adjusted to give cancellation of the interface pulse. The calibrated delay line and the attenuator are then adjusted to give cancellation of the second puise. The change in setting of the delay line gives the fractional part of a cycle or wavelength difference between the two pulses. but does not indicate the number of complete cycles forming the major part of the total phase diference. This number may be evaluated if the measurement is repeated at a slightly diferent frequency, obtained fror. a second oscillator a,. The two oscillators generate frequencies fi and fe, difering in frequency only by a few parts m a thousand. Thus a principal advantage of the system is that it is essentially a narrow-band technique. The electronic circuits can therefore be designed so that the variation in owTall phase shift on changing frequency is negligible elimmaung the possibility of errors arising on this account. Furthermore. the mean frequency of operation can oc chosen to comcide with the resonant frequency of the transducer. or with odd harmomes
\
. _ - . ~ - . - - - -. - , - . - - - . - - _ . - _ _ - - - - - -
810 A. J. Barlow and E. Yazgan
,O of this frequency. ensuring a higl. signal to-noise ratio in the received pulses. Previously developed systems using pulse cancellation techniques generally involve determination of several cancellation frequencies over a comparatively wide bandwidth. The present system 1
avoids the experimental difficulties inherent m this procedure and virtually eliminates the possibility of errors arising from frequency-dependent phase shifts in the electronic appara- i tus.
In addition, the need for the sound wave to make only one double transit of a short i liquid liquids. path makes this system particularly suitable for the measurement of highly al De high precision of the technique arises from the separate evaluation of the number o complete wavelengths in the liquid path and of the remaining fractional part of a wave-length.
The former, typically 50-300 with the frequencies and liquid paths used in the ,
present work, is determined exactly.
The fractional part of a wavelength is determined tothe in an delay accuracy governed by the measurement of the phase shift, given in turn by the chan line setting.
This measurement can be made with an accuracy to better than i 3*, giving approumately 3 parts in 106 overall.
Changes in velocity of this magnitude can therefore be detected; the absolute accul '
depends also on other factors discussed in @6.
- 3. Descripties of apparatus Two completely separate sets of apparatus have been constructed and used in the measure-ment of the velocity of sound in water.
One of thesesets operates at frequencies of 30000280 and 29 932800 Mc/s, the other at 10-011780 and 9 912014 Mc/s. These fre-quencies are measured by an electronic counter checked against standard frequency trans-missions.
The use of a continuous wave reference signal, controllable in phase and amplitude, nomssitates perucularly thorough screening of the basic oscillators and of all units precedmg the receiver. In addition, stability is of prime importance. The following descriptions give the relevant details of each unit.
3.1. Oseinators
,C Standard circuits have been used for the two crystalcontrolled oscillators required in
! each frequency range. Colpitts circuits using resonant quartz crystals operating in the i fnadamantal mode are satisfactory at 10 Mc/s; at 30 Mc/s third-overtone crystals operating in a Butler circuit are preferable. The crystals used are ATcut quartz, designed for zero ,
temperature coefficient around 25*c, and temperature stabshzation is therefore not required. '
Each oscillator provides an output of approximately 1 Y r.m.s.
3.2. Bufer avsph)fers b andg These buffers ahmmate any possibility ofinteraction between the ' acoustic' and reference signal channels. Each consists of a single broad-band stage with tuned output, having a voltage gain of about 3 and a bandwidth of at least 25 % of operating frequency.
- 3. 3. Diode gating circuit c This unit consists of a balanced four-diode switching network and is operated by a positive pulse of 100 v amplitude. During the application of the pulse, typically of Sasec duration, an output of 06 y peak to-peak is obtained. In the 'off' condition the output is less than 10-6 of this value. This rejection ratio in the gating unit is sufficient since the l overall rejection ratio of the transnutter channel is improved by class C operation of the following amplifier.
3.4. Transmitting amphper d he transmittmg amplifier consists of two broad band class A stages followed by a l class C push-pull output stage. The circuit is aligned to give a substantially flat response around the nominal operating frequency, to ensure negligible varianon in the overall phase
[
shift between the two slightly differing actual operaung frequencies. In the 'on* state of e
Sound celocity in water by pnase measurement technique 811 the gating unit a minimum of 25 v r.m.s. is generated across the transducer crystal, m the
'oK' state the output is less than 29v.
3.5. Bufer ampliper e This bufer serves to isolate the acoustic system from the continuous-wave signal present at the receiver input. A single untuned pentode stage is used and the gain of the ci cuit is approximately unity.
- 3. 6. Phase shift channel The uncalibrated phase shifter h consists of a conventional series RC circuit supplied from a low-impedance balanced transformer of 1.1 : I ratio. A switch preceding the transformer permits 180' phase change, and adequate variation of phase withm this limit I is given by values of R = 0-5kQ and C = 5-100 pr.
His circuit is followed by a single-stage ampliner, the primary function of which is to provide a source impedance equal to the characteristic impedance of the calibrated delay l line. Since the impedance of the delay cable is almost entirely resistive (7170) a ' wire-in' i triode of very low output capacitance is used with a non-inductive anode load resistor of 720. The cable is connected directly to the anode lead of the valve in order to minimize wiring capacitances. Series capacitors of appreciable reactance in the line are avoided by supplying the line drive circuit from a negative b.t. supply. ,
ne delay line consists of precision coaxial cable (Uniradio 21) with the lengths in circuit j joined by s.h.f. connectors (Plessey CZ70157 and CZ70159). By arranging the cable in two series of lengths, successive lengths in the $rst decade difering by 100 cm and in the second by 10 cm, only four pairs of connectors are in circuit for any setting. The design of these connectors makes it possible to adjust the length of each cable to i 01 cm. A constant impedance telescopic line, having the same h-6. tic impedance as the cable, is used for nne adjustment of the overall delay. His line has a maximum variation equivalent to 12 cm length of the cable.
{ The line is terminated by a matched resistance at the input of a single-stage wide-band ampliner with a gain of approximately unity. As in the line drive circuit, considerable care is noussary to minunize stray capacitance and inductance; a ' wire-in' pentode of very low input capacitance is used.
3.7. Piston attenuator m and compenst: ting amphfer I ne line termination stage is followed by a wide-band ampliAer having a gain of some 40 ds. His ampliner compensates part of the insertion loss of the piston attenuator, ne second stage of the ampliner is tuned, the coil forming the launching coil of the attenu.
ator. He attenuator is a circular tube of 0 750in. internal diameter; operation is in the Hit (least attenuation) mode. A Faraday screen is 6tted to eliminate other modes and to assist in ensuring the absence of phase shift along the waveguide. His essential require-ment is also ensured by maintaining suf5cient spacing between the launching and pickup coils to give a minimum insertion loss of 50 da.
He signal from the attenuator is passed through the bufer ampliner n and added to the outpu' of bufer e at the input of the receiver. These two bufer ampliners are the only active circuits in the system in which the signal level varies between initial and final measure-ments. By making them identical any variation of overall phase shift with signal level is automatically balanced since the signal levels in each are identical at cancellation.
l 3.8. Receiverf ne receiver is a conventional fixed frequency-tuned amplifier having a variable gam of 80 da maximum and a bandwidth of 1 Mets. De circuit is designed for rapid recovery from overload so that maximum sensitivity is restored less than 10 usec after the high-voltage transmitter pulse. The receiver output is displayed without demodulation on a wide-band oscilloscope (Tektronix 545A).
s
814 A. J. Barlow and E. Ya:gan
) Taue 2. Speciacation of gauge blocks Type Supplier Thickness Stated max. Exp. coeff. x 10*
CO*c) error (desc-')
(parts in 108)
Chromium carbide C. E. Johansson Ltd. 0 200000in.
Quality AA =t0 75 0 300000in. =0 67 75 Fused quartz E. Leitz Ltd. 340000mm =353 0 43 Class O 5 50000mm =202 0 43 6 50000mm =l 74 0 43 i
The length of the liquid path was defined by precision gauge blocks. Table 2 gives the specifications of these blocks. Three identical blocks were optically wrung on to the buffer !
rod, well clear of the path of the ultrasonic beam and the surface of the termination rod was in turn wrung on to the blocks. This process required considerable care, but was found to give values of velocity repeatable within experimental error, although the system was assembled and dismantled several times. Only a slight asial pressure was applied to the assembly, chie8y to prevent damage in the event of the system coming apart. Errors arising from compression of the blocks are therefore negligible.
The acoustic system was placed horizontally in the liquid sample to permit free circulation through the gap between bufer and termination rods. A holder similar to that described by McSkimin (1965) was used to support the system and to enclose the transduur end of the bufer rod. The amis of the acoustic path was approximately 10 cm below the water level.
- 4. 2. Water sample and temperature measurement Doubly deathd water was used throughout the measurements, this degree of purdication O, being considered adequate in view of the negligible efects of dissolved air (Greenspan and Tschiogg 1956) and of very small amounts of impurity (Weissier and Del Grosso 1951, Del Grosso et al.1954). The sl===== was contained in a small tank surrounded by a large bath. Conventional controls were used to stabilize the temperature of the water bath to a few malhdogrees. The specunen was gently stirred and precautions were taken to minimize cooling by evaporation. The temperature of the specimen was determined by a platinum r==taar* thermometer situated close to the acoustic path. This thermometer was calibrated, by the National Physical I.aboratory, shortly before making the series of measurements. Resistances were determined by means of a Smith Bridge to a precision corresponding to t 04)01 desc. No variations in temperature around the acoustic path could be detected and the temperature of the specunen remained constant to better than 0002 desc during a velocity measurement at a given temperature. The average ofinitial and final readmgs was taken as the temperature of meuvrement. As a check on the thermometer calibrauon, a second platinum resistance thermometer was used, the tempera-tures given by the two thermometers being equal within the accuracy of measurement.
The absolute w.cy of temperature measurement is estimated to be better than = 0003 desc. This figure corresponds to a velocity error of s 0 8 cmsec-1 around 25'c. reducing to zero at 74*c where the velocity in water passes through a rnaximum.
4.3. Efect of difraction on observed velocities The excess velocity due to disraction has been calculated for each frequency and liquid path length, by three distinct methods. These calculations are based upon the empirical c;.rve given by McSkimin (1960), the theoretical results of Bass and Williams quoted by McSkimin (1961) and the tabulated phase errors given by Del Grosso (1964L The results are shown in table 3.
Del Grosso has computed phase errors as a function of:A/a8. where :is the path length and a is the source radius. for values of 2ws/A up to 100w. For the source radius of 0 625 cm O
Sound relocuy m unter by ph'se a measurement technique 815 b
U Table 3. Excess velocity resulting from diffraction Values calculated for a beam diameter of 12 5 mm Frequency Liquid Cakulated excess velocity (msec-i) path Bass and Williams. McSbmin Del Grosso see McSkimin (1961) (1960) (1964) 30 13 mm 0419 0420 0 028 30 1I mm 0-021 0421 0430 30 6mm 0428 0428 0044
.o 0 6 in. 0417 0419 0426 30 0 4 in. 0 021 0422 0431 10 13 mm 0101 0143 0144 used in the present work, the values of 2wai A are 133w and 249w for frequencies of 10 and 30 Mets respectively. Although Del Grosso (1964), confirming the eerlier work of Williams (1951). states that for 2na/A > 50 the phase error is substantially independent of this parameter, there is some indication that for values of:Ala8 < 01 the phase error decreases slightly for values of 2ws/A exceeding 100w. The results in table 3 have been calculated assuming 2wa/A = 100w; it is therefore probable that the true values are slightly less than those given in the table. Accordingly, in the present work the excess velocity caused by distaction has been calculated using the theoretical results of Bass and Williams, quoted by McSkimin (1961). Table 3 shows that at 30 Mc/s the diferences between the correction calculated from the experimental results obtained by McSkimin (1960) and the corrections calculated using Bass and Williams' theory are negligible.
4.4. Errors arisingfrom phase change measurements Errors in the measurement of the fractional part of a wavelength in the acoustic path may arise in three ways: from the uncertainty in the lengths of cable, from the setting of cancellation points, and by deviations from linearity of the phase characteristic of the line, p ne length of each cable was adjusted to i 01 cm; the maximum possible error on g' changing from one pair of cables to a second pair is therefore = 04 cm. At 30 Mc/s the corresponding phase error is i O 22'. It was found possible to deternune cancellation points to about t' of phase angle; the maximum possible error between two settings is thereforei}*.
Deviations from linearity of phase change on varying the length of the line arise from standing-wave efects caused by mismatching at the termination and source of the line.
To a first approximation, the error e associated with a phase change 8 is given by (A. J. Barlow 1959 Ph.D. Thesis,1.ondon University) e = i 2r.r:0 (14) where r, and ri are the magrutudes of the reflection coefficients at the source and load re-spectively. Reflection occurs mainly as a result of reactive nusmatch. The maximum error occurs when 6 = 180". For the delay system used (Barlow 1959 Ph.D. Thesis).
2r.ri < 0 01 at 30 Mc/s; the maximum phase error is then less than = l 8'.
He total maximum possible error in a particular determination of 8 is therefore approxi-mately i 2 7*. For tne three longest liquid paths and a frequency of 30 Mc/s this figure corresponds to a trsximum possible error in velocity of about = 005 msec-L.
Errors in the determmation of the length of cable equivalent to one wavelength are l negligible. since seeral measurements were taken at each frequencyf andf using diferent pairs of cables, and the average value was calculated.
- 4. 5. Experimental results
! Typical results for the values of the velocity of sound in twice distilled water are given
' in table 4 Each value represents the average, given to the nearest 0 01 msec-5, ot' the two results obtained from measurements made at the slightly didering frequencies f3 andfs.
In general, the two results difered by less than 043 msec-L. The values shown have been i
O
-=
lfV 816 A. J. Barlow and E. Ya:gan Table 4. Experimental values of the velocity of sound in distilled water (a) Frequency 30 Mets,6 5 mm gauge blocks Temperature Velocity i A Average A Temperuure Velocity a Average a
('c) (m sec-') (m sec-') (m sec-8) ('c) (m sec-')
< (m sec-5) (m sec-')
23 503 1492 49 0 41 45 127 1536 46 0 43 24437 1493 94 0 46 49 966 1542 43 0 40 4
24 905 14 % 34 0 40 55 105 1547 36 0 43 25 125 1496 90 0 40 64 980 4
1553 35 0 40 25 380 1497 59 0 43 70450 l 1554 75 0 33 25 707 1498 43 0 43 0 40 25 812 1498 73 0 41 71 160 1554 89 0 40 25 910 1498 99 0 40 72480 1554 98 0-39 0-42 73450 1555 42 0-42 27 570 1503 24 0 37 73 900 1555 47 0 40 27 935 1504 10 0 40 74 200 1555 49 0 38 29 920 1508 84 0 41 75440 1555 42 0 43 29 323 1507 49 0 39 76 220 1555 40 0 41 29 985 !$0942 0 38 77430 1554 92 0 39 35420 1519 72 0 44 78 310 1554 70 0-42 39 990 1528 78 0 38 79 115 1554 61 0 39
, 80 045 1554 39 0-41 0-40 f
(6) Frequency 10 Mc/s, 6 5 mm sauce blocks Temperature Velocity
{ A Awrage A Temperature Velocity A Average A !
('c) (msec-5) (msec-8) (m sec-8) ('c) (msec-') (m sec-') (m sec-')
23 340 149240 0 44 55446 1547 36 0 39 25 307 1497 37 0 44 62 780 1552 33 0 47 O 25 425 147772 0 40 ]
(*) 25 562 25 705 149803 149845 0 45 0 41 7} 950 74 220 1554 88 1555 48 0 38 0 39 0 42 i 0 43 78 130 1554 73 0 43 3 34 990 1519 73 0 37 0 40 46 131 1537 77 0 46 l corrected for the effect of diffraction, and the expansion of the gauge blocks with increasing ;
temperature has also been taken into account. Table 4 also shows the amount A msec-L by which these values are lower than those calculated from the results obtained by Green-span and Tschiegg (1957). The rate of variation with temperature found by Greenspan and Tschiegg is generally regarded as being substantially correct (McSkimin 1965). The t average values of a for temperature around 25 and 74*c and for the intertnediate rante are also given.
- 5. Analysis of expedoestal results In an analysis of the experimental results it is convenient to distinguish between three groups of variables which may give rise to errors. The first group consists of those factors which either give constant errors throughout the whole series of measurements or cause random variations which are negligible compared with other random errors. " Ibis group incluces temperature, specunen purity, pressure and frequency. The second group com- .
prises those variables purposely changed during the measurements; these include differences I between acoustic path length, operaung frequency and diffraction corrections. In the third
- group are the main random errors. )
For the present measurements the spread of random errors in velocity should result !
entirely from the uncertainues of phase measurement and therefore be a maximum of !
- 005 msec-5 " Ibis is confirmed by the experunental results, the values of A varymg l by not more than this amount for a given frequency and path length.
O [
G i l
I
. . _< _ . _ _ _ _ _ - _ .. _ - - _ - _ _ . ~ _ . . _ . . _ _ _ _ _ _-
Sound velocuy in water by phase measurement rechnique 817 l
The results obtained using the 6 5 mm gauge blocks at frequencies of 10 and 30 Mc.s i
are m good agreement. as may be seen by a comparison of the average a figures for cor-l responding temperature regions. Essentially this agreement substantiates the diKraction '
theory, since the diffraction correction of 0101 msec-8 at 10 Mets is apprectable. It can therefore be assumed that any errors in the diKraction corrections applied at 30 Mcis are negligible.
The average a 63ures in the region around 74*c show that the results at 30 Mc/s obtained !
with the 6 5 mm,0 3 and 0 2 in. gauge blocks, for which the highest accuracy is claimed.
I are in precise agreement, with A., = 0 40 msec-5 The 5 5 mm blocks give A., = 0 42 I msee-1 and the 3 0 mm blocks give 3., - 0 39 msec-1 These averages are correct to '
the nearest 001 msec-5 These diNerences have been confirmed by an extensive series of measurements made using a sample of water taken directly, withour, purification. from the public supply. An average velocity consistently 005 msec-5 higher than that for distilled ;
water was obtained over the range 23-80*c. but the relative differences between the five sets of blocks remained the same. It follows that the average thicknesses. taken over each l
set of three blocks of the 6 5 mm. 0 3 and 0 2in. blocks are within :: 0 7 parts in 10' of
! their norrunal values, since this h the stated accuracy of the 0 3 in. blocks. The average deviation from the nominal value for the 5 5 mm block is then probably between -0 6 and -- 2-0 parts in 105, the corresponding figures for the 3 0 mm blocks being 7 and
- 14 parts in 106 These deviations are well within the limits speca6ed by the manufac-l turers.
l Considering only the results obtained in the region of 74'c at 30 Mc/s. the average value of a for the 6 5 mm,0 3 and 0 2 in. seu of gauge blocks is 0403 msee-5 This 6gure is unchanged if the results obtained with the other two sets of blocks are included, the value of a being decreased by 0-02 msec-5 for the 5 5 mm blocks and increased by 041 msec-5 for the 34 mm blocks. The standard deviation is 0414 mnec-5 and the distribution of the a values around the mean is very close to a normal distribution, as may be expected from i
the random nature of the phase measurement errors.
l Applying the same procedure to the results obtained at 30 Mc/s around 25'c, the average value of a is found to be 0412 msec-1, with a standard deviation of 0420 msec-8 The Q slight increase in standard deviation is probably partly due to the uncertainty in temperature measurement.
The small difference in A., between c. 74*c and c. 25'c is =omewhat larger than could be expected from the estimated possible error in absolute temperature measurement. It is probable that this discrepancy represents a slight difference between the variation of l velocity with temperature found by Greenspan and Tschiegg (1957) and that found in the present work, but it would be unrealistic to regard the difference as signi6 cant. In general it is seen that the present measurements confirm the variation of velocity with temperature found by Greenspan and Tschiegg (1957), but the actual values of velocity are approximately 0 40 msec-8 lower.
A fifth-degree polynomial has been fitted to the experimental results by means of a com-puter, the fit being such as to give a minimum mean square error. The data for all five sets of blocks were used, those for the 5 5 mm and 34 mm blocks being modified as indicated previously. The resulting equation is V = 1400 7873 189939T - 6 394257 4 10-87'
- 4 4060241 x 10-*75 - 2 N9801.< 10-*T* l
- 6 214865 x 10-'T' mso:-' (15) i l
where Tis the temperature in 'c. '
The standard devianon of the data from this curve is icas than 0418 msec-5 The maxi-mum deviauon of any single measurement from the curve is 0 041 msec-8. and the deviations of the data from the curve are apparently random and are substanually in accordance with a normal distribution. This scatter is adequately accounted for by the possible errors m phase rnessurement; the extent of the scatter is approximately two thirds of that obtained a
i
.s l
l l
l l
-- . .= .-
l l
1 818 A. J. Barlow and E. Ya:gan
=
by Greenspan and Tschiegg (1957) using the 'smg-around' technique. No signi6 cant reduction of these values is obtained by using a polynomial of higher order. j Equation (15) has been used to calculate the velocity of sound in water at I dege intervals l from table 5.23 to 30'c, the range over which this equation is valid, and the results are given m Following Greenspan and Tschiegg (1957). the increase for each I dege interval 4
is also given to facilitate interpolation.
Tahie 5.
Velocity of sound in water, values alal=*ad using eeuktion (15), together with the increase in velocity per des C
! T V Increase T V
]
lacrease T F Increase
(*c) (m sec-') (msec-') (*c) (m sec-') (m sec-') (*c) (m sec-')
23 0 1491 46 -
(m sec-')
43 4 1533 47 1 51 63 4 1552 50 0 49 24 4 1493 86 2 80 44 0 1534 91 1 45 64 0 1552 95 0-45 25 4 1496 58 2 72 45 0 1536 31 1 39 65 0 1553 35 0-40 26 4 1499 22 2 64 46 0 1537 64 !
1 34 66 4 1553 71 0 36 27C 1501 79 2 57 470 1538 93 1 28 1
28 0 1504 28 2 49 67 0 1554 42 0 32 I 48 0 1540 15 1 23 68 0 1554 30 0-27 29 4 1506 70 2 42 49 4 1541 33 j F17 69 0 1554 53 0 23 30 4 1509 04 2 34 50 0 1542-45
- 1 12 70 4 1554 72 0 19 31 0 1511 31 2 27 51 0 1543 52 147 324 1513 52 2 20 71 4 1554 87 0 15 !
52 0 1544 53 102 72 0 1554 97 0 11 33 0 1515 65 2 13 53 0 1545 50 0 97 4
34 4 1517 72 247 73 0 1555 44 007 54 0 1546 42 0-92 74 4 155547 043 35 0 1519 72 200 55 4 1547 28 0 87 36 4 1521 66 1 94 75 4 1555 05 -001 56 0 1548 10 4 82 76 0 1555 00 - 0 05
! 370 1523 53 1 87 57 0 1548 87 0 77 38 0 1525 34 1 81 77 4 1554 91 -009 58 4 1549 59 4 72 78 4 1554 78 -013 n 394 152748 1 75 59 4 1550 26 0 67 79 0 1554 61 - 0 17
- V} 400 1528 77 41 4 1530 39 1 69 l 62 604 1554 89 61 0 1551 47 4 63
& 58 80 4 1554 41 -020 42 4 1531 96 1 57 62 4 155241 0 54 j 6. Diseassion Measurements of the velocity of sound in water show that the experimental system de-scribed here is capable of extremely consistent results. The scatter of the data is small and follows a normal distribution. Since most of the scatter can be attributed to imperfect matching of the delay line, further development of the system could probably reduce the scatter by a factor of two.
'There is no evidence of any systematic errors arising from the use of diferent acoustic path lengths or discrent operating frequencies. During a separate series of measurements investigations were made into the efects of varying the amplitude and duration of the transmitted pulse and of changmg certain critical components of the system including the bufer ampliSers and piston attenuator. Such changes gave no diferences in the rnessured velocities. Results were also obtained, using the 3 mm blocks at a frequency of 30 Mc/s, on pulses which had made two and three double transits of the liquid path. Again no variations in the values of velocity were found.
It follows that the results obtained represent true values of the velocity of sound in the liquid measured. It relating such values to the absolute value for the velocity of sound in water those factors which may give errors constant throughout the whole series of measure.
ments must be considered. At 23*c the possible error of ::: 0003 degc in absolute tempera-ture measurement gives a possible error of 04)08 msec-* in velocity. At 74*c, where the velocity passes through a maximum the error is negligible. The edect of hydrostatic pressure on velocity causes the values obtained to be high by 0002 msec-8, due to the head of water above the acoustic path. Errors resulting from the varianon of atmospheric pressure are negligible. The attenuauon in water gives errors of less than 1 part in 10*:
errors in the determination of operaung frequencies are also negligible.
Dissolved air was probably the principal impurity in the sample of water investigated.
\
-. . .- .. ... . - . . , - .=- . ._ - -- -. -..
Sound telocuy w water by phase measurement techmque stg Greenspin and Tschi1gg (1956) conclude that dissolved air increases the velocity m water by less than I part in 108 and around 30*c the increase is possibly of the order of I part in 10*. This latter figure is negligible; even if the difference is significant. it would seem preferable to regard the velocity of sound in water saturated with air as a standard for reference. since this is the normal state of water in contact with air.
V It may therefore be deduced that the only signtScant sources of possible error in the results are the uncertainties in acoustic path length, in the determination of temperature. and the standard error of the data. The sum of these possible errors is = 0 024 msec-5 at 74*c and = 0 038 msec-1 at 25'c. From the present measurements, the velocity of sound in water to the nearest 041 msec-5 is found to be 1496 58 = 0 04 msec-L st 25 000*c and 1555 07 = 003 msec-1 at 74 00*c. The accuracy of these values is believed to be the I
highest yet attained. The results are in close agreement with the values found by McSkimin (1965). !!gunas et al. (1964). Neubauer and Dragonette (1964) and Brooks (1960).
Acknowledgments The authors wish to thank Professor J. Lamb for his constant help and encouragement 3 in this work and for the provision of facilities. Thanks are also due to Dr. E. A. Bruges 1 for the use of the Smith Bridge and the authors are grateful to Mr. A. T. J. Hayward for bis interest and assistance. The work was supported by a contract with the National Engineering Laboratory, Ministry of Technology.
References BARTHE1., R., and Not.tz. A. W.,1952, J. Acoast. Soc. Amer., 24, 8-15.
Baoots, R.,1960, J. Acomt. Soc. Amer.,32,1422-5.
Det. Gaosso, V. A.,1964, U.S. Namel Res. Imb. Rep. No. 6026. ,
Det Gaosso, V. A., SMuaA, E. J., and Foucsas, P. F.,1954 U.S. Naval Ars. Lob. Arp. No. 4439. '
GatsNsPAN, M., and Tscansoo, C. E.,1956, J. Acowt. Soc. Amer.,28, 501.
1957. Rev. Sci. Instrum., 28, 897-901 ; /. Res. Nat. Amr. Stand., 99, 249-54 ItovNAs, V., Kuna.YuNsNs, O., and YArsaTAs, A.,1964, Samt physses-Acoustics,10. 44-8.
McSKIMIN, H. J.,1957, J. Acoust. Soc. Amer., 29,1185-92.
1960, J. Acost. Soc. Amer.,31,1401-4.
1961, /. Acourt. Soc. Amer.,33,539.
1965, /. Acowr. Soc. Amer.,37,325-8.
g NevaAusa, W. G., and DaAoowrrra, L. R.,1964, J. Acoust. Soc. Amer.,36,1685-90.
Scitutz, A. K.,1955,-Z. anrew. Phys.,7,144.
Wressa.sa, A., and Det Gaosso, V. A.,1951, /. Acoust. Soc. Amer., 23, 219-23. I Wr= A. O.,1951, J. Acomt. Soc. Amer.,23,1-6.
Wtt. son, W. D.,1959, /. Acoust. Soc. Amer., 31,1067-72.
l O
l l
Speed of Sound in Pure Water V. A. Del. Gnos&O AND C. W. MADEs Nened Amerch I.dermaery, Washengase, D. C. A/Jf0 (Received 26 May 1972)
A sound epend equation of 6fth order m temperature is 6t with a standard deviauon of 0.0028 misee to 148 oeservatises bete.en 0.00l*C and 95.126*C on the T. scale. The accuracy is beheved to be 0.015 misse, and the reproduability over replicauons is 0.005 m/sec.
Strainer Cz.assrFtCADOW: 13.3.
UtTRODUCTION with emphasis about this temperature but extending In the course of obtaming a satisfactory sea-water the total range closer to both O' and 100'C, are now sound speed equation based on laboratory measure- E ments,* data were obtained in pure water8 with an apparent reprodudbihty of better than 4 ppm. In this L EIPERIMENTAI, METHOD latter reference, it was demonstrated that by compari-Sound-speed measurements were made indirectly by son of results of reputable observers, the speed of sound in pure water could be speoned to better than means of the ultrasonic interferometer whose construc-tion and operation have been dancussed earlier.
O.05 m/sec. Mention was also made therein of indica. Brie 6y, acoustic wavelengths are measured by electron tions of an anomaly near 4*C. These measurements, ically noting some charactenstic of a quartz crysta!
TABI.E I. Souhd speeds meneered in pure water for teasperatures ce To scale.
Temp *erature Seemd speed Temperature Sound speed Temperature Sound speed Temperature
( C) (m/sec) (*C) (m/sec)
Sound speed
(*C) (m/ast) (*C) (m/sec) 0.0010 1402J95 3.4933 1419.287 1.0035 1407.384 0.0020 1402J98 3.7972 7 9894 109.089 0.0030 1M.702 1.0035 1407 384 7.9s04 1402.404 3.7982 1 2 .494 1U9.094 0.0030 1402.406 1.00 0 1407J92 7 9904 109006 3.7992 1420.700 1.0045 0.0110 1402.445 1407386 7.9904 109004 0.0120 3.8002 IM.707 1.0055 1407J91 7.9914 1402.448 3J002 1420.707 1439.102 0.0130 1.0095 1407.412 9.9537 1447.087 1402.456 3.9911 1421.584 0.0!JO 1.0175 1407.451 9.9537 1447.087 1402.453 3.9911 1421.587 0.0140 1402.459 1.0235 1407.482 9 9547 1447.094 3.9921 1421.590 1.0305 0.05E 1402.649 3.9921 1421.589 1407.516 9.9547 1447.091 0.0520 2.0490 1412.468 9 9547 1447.089 1402.652 3.9931 1421.595 0.0520 1402.640 2.0540 1412.501 39 9657 1528.809 4.2100 1422.620 2.0620 0.0530 1402.654 1412.527 39 9777 !$28.131 4.2170 1422.624 2.0650 0.0530 1402.654 1412.543 39 9887 1528.847 4.2170 1422;622 2.0680 0.1979 1403J83 1412.554 59 9924 1550.980 4.2170 1422.622 2.0720 0.1979 1403.383 1412.574 60.0034 1550.986 4.5269 1424.Q12 2.4868 0.1999 1403J90 1414.553 60.0124 1550.994 4.5279 1424.039 2.4868 0.1999 14Q3J88 1414.556 60.0204 1550.998 4.5279 1424.040 2.4898 0.1989 1403.388 1414.573 60 0294 1551.004 4.5279 1424.039 2.4918 0.4878 1404.829 1414.582 70.!! 90 1554.819 5.4935 1428364 2.4928 0.4898 1404.843 1414.585 70.1210 1554 819 5.4935 1428.365 2.9736 0.4908 1404.848 1416.861 70.1240 1554.819 5.4945 1428.367 2.9746 0.4988 1404.888 1416.864 70.1340 1554.824 54965 1428 378 2.9766 0.5008 1404.894 1416.875 70.1500 1554 824 59892 1430.543 2.9766 0.5018 1404.901 1 1416.576 90.0858 1550.430 5.9902 100.548 3 4913 1.0005 1407.365 1419.279 90 0868 1550 430 5.9902 1430.551 3 4913 1.0025 1407J77 1419.277 95,1214 1547.096 5.9922 1430.559 3.4923 1.0025 1407.382 1419.277 95.1224 1547.100 5.9952 1430.572 3.4923 1 1419.280 95.1264 1547.095 1442 vesene 52 Number 5 IPar 21 1972
)
i SPEED OF SOU N D IN P 11 R E WATER Tasts 11. Previous sound. speed measurements in pure water with temperatures converted to T scale Temperature Sound speed Temperature Sound speed
(*C) (m/sec) (*C) imineci Temperature Sound speed Temperature Sound speed
(*Cl i misec > (*C) tmisse) 0.0540 1402.673 29 9816 1509.081 9 9917 1447.234 0.0610 1402.695 29 9836 1509 000 49 995o 1542.545 0.0640 9 9957 1447.249 50.0126 1402.705 34.9710 1519 752 1542.563 0.0600 10.0027 1447.276 - 50.0366 1402.726 34.9810 1519.768 1542.591 0.0720 10.0117 1447.307 50.0466 1402.747 34.9870 1519.781 1542.602 4.9087 19.9196 1482.091 60.0194 1426.115 39.9727 1528A20 1550.999 4.9917 19.9306 1482.006 60.0124 1426.126 39 9747 1528 823 1550.999 4.9927 1426.129 19.9216 1482.102 73.9957 39.9777 1528.827 1555.144 4.99J7 1426.1J1 24.9815 1496 636 74.0117 39.9847 1528.837 1555.144 24.9855 1496 646 74.0218 1553.145 Tanut III. Coedhaents for Eq.1 loc sound speed in m/sec.
& TatdeI6t Tab 6e II 6t Combined 6t 0 0.140238689X10' O.140238749X10' 1
0 (nuaananX108 O.140738754 x10' 2 0.503699148X 108 l
-0 tanataa99X10-5 0.503711129x108 3 -0.500268809X 10" -0.500852166X 10-8 0.334817140X10-8 0.331767408X10" 4 OJ34198U4x10"
-0.1#252527 X 10-* -0.1M373838 X 10-*
5 0J2391J472X10-* -0.147800417x10" 0.298841057 X10-* 0.31460091X10" i
l en T sale with standard devianon as 0.003 m/sec.TAaaa IV. Speed of sound la pure ~er in m/sec. Calcul i
To
- C 0.0 0.1 0.2 03 0.4 OJ 0.6 0.7 OA 0.9 0 1402JES 1402J91 1 1403J03 1403.893 1404JR3 1404JP2 1405.399 1405AB5 1406JI0 1406.874 2 1407J67 1407.439 1412.232 1412.712 140BJe9 1413.192 1408A38 1413.670 1409J27 1414.147 1409314 1410J00 1410.784 1414.62 1411.268 1411.751 3 14166985 1417.454 1415.097 1415J71 1416.043 1416.515 1417.922 1414J89 1418.855 4 1419.3 2 1419.784 14 3.246 1 2.75
) 1421.628 1422.006 . 1422.543 1422.999 1423.454- 1423.908 1434.361 1421.168 5 1424A13 1425Je4 1425.713 6
1436.162 1436.409 1427.056 1427.501 1427.946 1428J89 1428.831 1430.509 1431.026 1431.M2 1431.897 162J31 1432.764 1429.272 1429.712 1430.131 14M.912 1435J39 1435.7M 14M.189 1436 412 167.035 1433.196 1433.626 164.056 1434A85 7
8 1437.456 1437A77 IG.296 1438.715 9 1439.132 1443.251 1439J49 1439.964 1443.657 1444.062 1440J78 1440.792 1441.204 1441415 IM2.026 1442.G5 14423 0 10 1444A67 1444.870 1445.273 1445.674 1446.074 1446.474 1446.872 11 1447.270 1447.666 1448.062 1448.456 1448A50 1449.243 1449.634 1450.025 1450.415 1450.803 12 1451.191 1431.578 1451.964 1452.349 1452.733 1453.116 1453.498 1453J79 1454.259 1454A38 13 1455.016 1455.394 1455.770 1456.145 1456.520 1456A93 1458.747 1459.115 1457.266 1457.637 1458.008 1458J78 1459.482 1459A48 1440.213 1400.577 14 1462 384 1462.743 IMI.101 1463.458 1463A14 1460.940 1461J03 l # 1.464 1462.025 15 1464.169 14M.523 1465.931 1464.876 1465.229 I # 5.500 l 16 1446JE0 1406 429 1486 977 1467 324 1467 470 1468.015 1468J59 1448.703 1449.045 i 17 1409387 1489.728 1470.067 1470A06 1470.745 1471.082 1471.418 1471.754 1472.755 1473.087 1473.418 1473.748 '1474.078 1472.088 1472.422 l: 18 1474.406 1474.734 1475.061 1476.036 1476.359 1476.e82 1477.003 1477.324 1477.644 1475Ja6 1475 712 19 1479.231 1479J46 1479Aeo 1400.174 1477.963 1478.282 1478.599 1478.916 l
20 1480 486 1480.798 1481.108 1481.418 1481.727 1482.035 1482J43 1482.649 1482.955 1483.200 1483.564 1483.368 21 1485J72 1485 670 1485.908 1486.264 1484.170 1484.472 1484.772 1485.073 22 1486J40 1486A56 1487.150 1487.443 1487.736 1488.028 1488 J19 1488.610 14M J99 1489.188 1409 476 1489.763 23 1491l87 1491A09 l#1.751 1 # 2.032 1492.312 1492.591 1490.049 1490.335 1490 620 1490.804 i
' 24 1493.976 1494.250 !#4.524 1494.797 l#5.070 1495J41 1492.870 1493.147 1493 424 1493.700 25 1496A87 l # 6.954 1495.612 1495.382 1496.151 1496 420 26 IW7.220 1497 486 1497.751 1498.014 1498.278 1498.540 1499323 1499.582 1499.841 1498.802 1499 063 27 1500.000 1500356 1500.612 1500.808 1501.123 1501377 1501.630 28 1501.883 1502.135 1502J06 1502A37 1502A87 1503.136 1503.384 1503 632 1504J70 1504A15 1504.858 1505.102 1505.344 1503.478 1504.124 l 29 1505.586 1505.827 1506.067 1506J07 1506.784 1507.022 1507.258 1507.494 1506.546 l 1507.730 1507.964 1508.198 1508 431 JO JI 1509.127 1509357 1509J87 1509216 1510.044 1510.272 1510.499 1510.725 1508.e64 1508 896 1511.399 1511A23 1511.845 1510 950 1511.175 32 1513A03 1512.004 1512.299 1512.510 1212.730 1512.949 1513.167 1513 385 33 1513.819 1514.035 1514.250 1514.465 1514.679 1514 392 1515.104 1515.738 1515.948 1536.137 1516.365 1516.573 1515.316 1515 527 34 1516.700 1516.987 1517.193 1517.J98 1517.602 1517.806 !$18.009 1518.212 1518.414 1518 415 1518.815 1519.015 35 1519.808 1520.005 1519.214 1519 413 1519 611 1520.201 1520.396 1520.591 36 1521.745 1521.935 1520.785 1520.978 1521.171 1521.363 1321.554 1522.125 1522.314 1522.502 1522.690 1522.877 37 1523.618 1523.802 1523.985 1523.063 1523.249 1523 434 1524.168 1524.350 1524.531 38 1525.428 1525A06 1525.783 1524.712 1524.892 1525.071 1525.250 39 1525.959 1526.135 1526.J10 1526.464 1526.658 1526 132 1527.176 1527.348 1527J18 1527.004 1527.609 1527458 1528.027 1528.195 1528.363 1528.530 1528.697 The Jooesel of the Acessencel Secwy ei Amenes 1443
___ _ . . _ ~____-.__.___-__-_._____._.__.-.-.-_____.m ~... . _
1 1
' j D E 1.
l GROSSO AND MADER TASUL 1Y. (conhamed) a
{
- r. -
- C 0.0 0.1 0.2 03 0.4 03 0.6 0.7 0.8 0.9 i 40 1528.863 1529.028 1529 193 1529.357
] 41 1530.489 1529.521 15J0.649 1530.807 1530.965 1531.123 1529 684 1529 846 1530 008 1530.169 1530.J29 7 42 1532.056 1532.210 1531.280 1531.436 1531.392 1532.362 1532.515 1532.666 1531.747 1531.902
{ 43 1533.564 !$33.712 1532.818 1532.968 1533.118 j 1533.459 15M.006 1134.152 1513.267 1533.416 44 1535.015 15J5.157 1534.297 1534.442 1534.586 1535.298 1534.730 15M.873 e
45 !$36.409 1536.545 1535 439 1535.579 1515.719 1535.858 1535.997 1536.134
{ 1536.681 1536.816 1536.950 1537.004 15R272
- - 1537.7 # 1537.877 1538.007 1527.218 1537.351 1537.4&3 4
47 1538.137 1538.266 1538.394 1537.6l3 1539.028 1539.154 1539.278 1538.522 4
48 1539.402 15J9.526 1539.649 1538 650 1538.776 1538.903 1540.256 1540J76 1540.495 1540.614 1539.772 1539 394 1540.015 1540.136 l # 1540.732 1540.850 1540.967 1541.430 1541344 154t458 1541.772 1541.0U 1541.199 1541 315 4
50 1541.885 1541.997 1542.109
! 1542.551 1542.edo 1542.768 1542J77 1542.984 1542.220 1542.131 1542.441 31 !$43.619 154J.723 15 0.091 1543.198 1543J04
( 1543.826 1543.929 1544.032 1543.409 1543.514 52 1544 436 1544.734 1544.134 1544.235 1544 813 1544.931 1545.028 1545.125 1544J36 1544.436 1544.536 53 1545.601 1545. # 5 1545.221 1545.317 1545.412 1545.788 1545.881 1545.973 1546.065 1545.507 54 1546JIT 1546.605 1546.694 1546.156 1546.247 1546.337 55 15#.781 1546.869 1546.955 1547.042 1546.427 1547.J82 1547.466 1547.549 1547432 1547.128 1547.213 1547.298 1 56 1547.715 1547.796 1547.878 i 1548.199 1548.278 1548.356 1548 434 1548.512 1547.959 1548.Q39 1548.119 l j 57 1548.589 1548.665 1548.967 1549.041 1549.115 1549.188 1548.741 1548.717 1548.892 e 58 !$40 687 1549.756 1549.200 1549.313 1549.405 IM476 1549.547 1549 825 1549J94 1549.962 1550.029 1549.617
] 59 1550J40 1550.425 60 1550.489 1550.553 1550.616 1550.679 1550.006 1550.163 1550.229 1550.295
!$50.741
" 1550.986 1551.046 1551.106 1551.165 1551.224 1510J03 1550.865 1550.926 61 1551.566 1551.622 1551.282
( 62 1551.677 1551.731 1551.340 155tJ97 1551.454 1551.510 1551.786 1551 839 1551JD2 1551.M5 1551.998 1552.049 3 63 1552.101 1552.152 1552.202 1552.252 1552J02 1552.3311552.400 1552.448 1552.496 1552.590 1552.637 1552.643 1552.543 i 64 1552.*29 1552.774 1552.818 i 1553.E15 1553.078 1553.119 1553.100 1553.201 1552.863 1552.907 1552.950 1552.993 65 1553.241 1553.281 5 1553.437 1553.474 1553.512 1553.548 1553.585 1553J21 1553Jeo 1553 Jet 66 1553421 1553 456 1553.7M 1553.428 !$53Jd0 1553J03 1553.925 1553.957 1553. # 1 1553.726 1533.700 l 67 1554.109 15M.1JB 1554.167 1553.988 1554.019 1554.040 1554.079
+
l 68 1554.195 1554.223 1554.250 1554.277 1554J04 15MM 1554J56 69 1554JBI 1554.406 1554.430 1554.454 1554.478 15M.501 1554.524 i 1554.611 1554.632 1554 452 15 R 672 1554.691 15M.546 1554.548 15MJ90 70 1554.710 1554.729 1554.747 1554.765 1554.782
! 71 1554.799 1554J16 1554 432 1554J48 1554.863 1554.878 15MAIS 1554.M7 15M.959 1554.971 15R 983 1554.994 1555.005 1554.907 15M.930 15M.9M 72 1555.015 1555.036 1555.055 1555.044
- 73 1555.053 1555.062 1555.070 1555.077 1555.085 1555.091 1555.098 1555.104 1555.110 1555.115 j
4 74 75 1555.120 1555.146 1555.1471555.134 1555.128 1555.147 1555.146 1555.132 1755.146 1555.155 . 1555.138 1555.140 1555.142 1555.
1555.145 1555.143 i 1555.141 1555.1Je 1555.1J6
% 76 77 1555.133 1555.081 1555.0741555.1JD
!$55.006 1555.126 1555.058 1555.122 1555.080 1555.0411555.117 1555.112 1555.107 1555.101 1555.09
.i 1554.991 1554.980 1554.988 1554.956 1554.944 15M 331 1555.032 1555.022 1555.012 1555 002 78 1554.918 1554.905 1554J91 15MJ77 79 1554.862 1554J47 1554.832 1554J16 1554.800 1554.784 1554.767 1554.750 1554.7J2 1
80 1554.896 1554 477 1554 458 1554439 1554.619 1554.599 1554.578 1554.557 1554.5M 15 81 15M.#2 15M.470 1554.251 1554.225 1554.447 1554.199 1554.1721554.424 1554.1441554.400 1554.117 1554J76 1554J52 1554J27 1554J02 1554.2 82 1553.974 1553.944 1554.089 1554.061 1554 032 1554 083 83 1553.914 1553.883 1553J52 1553.821 i M 1553 Ado 1553 426 1553.592 1553358 1553.524 1553.489 1553.789 1553.758 1553.725 1553.454 1553.418 1553.383 1553J46 1553.883 85 1553JIO 1553.273 1553.235 1553.198 1553.100 1553.121 1553.083 1553.044 1553.004 1552.964 l 86 1532.9M 1552J84 1552J43 1552.802 1552.760 1552.718 1552.304 1552.440 1552.415 1552A76 1552A34 1552J91 1552.547 87 1552.048 1552.001 1552 371 1552.326 1552.200 1552.234 1552.188 1552.142 1552.095
} 88 1551 358 1551.307 1551.953 1551.905 1551.856 1551.807 1531.758 1551.700 1551A59 1551.009
- 1551.456 1551.404 1551.352 89 1551.300 1551.248 1551.195 1551.141 1551.088 l* 90 1551Al4 1550.9W 1550.925 1550J70 1550.815 1550.759 1550.703 1550.M7 1530.500 1550.533 91 1530.474 2350.418 1580J40 1550J02 1550.243 1550.184 1550.125 1550.065 1550.005 1549.M5 1 1549J84 1549.823 1549.742 1549.700 1540438 1549.576 92 1549.513 1549 450 1540.387 1549.323 1549.259 1549.195 1549.131 1540.066 1549 000 1548.935 1548.869
} 93 1548A02 1548.534 1548.467 1548.8m3 1548.7J6 1548.M9 3 M 1547.912 1547.841 1548.398 1548J30 1548.261 1548.192 1548.122 1548.053 1547.983 95 1547.190 1M7.116 1547.770 1547.699 1547A27 1547.555 1547.483 1547.410 1547.3J7 1547.2M
$ 1547.042 1546.967 1546.892 1546.817 96 1546.741 1546A65 1546.589 1546.513 j 1546.436 1546.359 1546.281 1546.204 1546.126 1546.047 1545.960 97 1545A51 1545.570 1M5.490 1545.400 1545.328 1545J90 1545.810 1545.731 1
98 1544 234 1544.751 1544 467 1545.246 1545.lM 1545.082 1545.000 1544.917 i 99 1544.583 1544.499 1544.414 1544 329 1544.244 1544.159 1544.073 3 100 1543.987 1543.900 1543J14 1543.727 1543A39 1543.552 1543.464 1543J76 1543.287 1543.198 1543.109 1
e i
I operated in a continuous wave iterative.redection leads to a speci6 cation of accuracy of 10 ppm or 0.015 technique and counting these imposed characteristics m/sec.
as the redector-source separation is varied. The path j gg change for some 300 acoustic fringes at 3 MHz k
} measured by a laser interferometer. Consideration of Some 112 new data points for the speed of sound in
{
all sources of erfor, including theoretical predictions" pure water were taken in 1970 and are reported in 1
Med votes 52 Nesser 5 tPoe 2) 1972 l
i
. . - . _ - - - . . - . - - -.. _- . . - - . - ~ . - _ . - - - - - . . _ . - -
t 5,
J SPEED OF SOU N D IN PURE WATER Table 1, with temperatures on the Tu scale. In Table H, TASLt V. Reeranoon curve devsauon averate and scatter for the previous measurements 2are repeated with tempera. "*"""* **E*""'***I*P"**" "
i[ tures converted to the same scale. The results of these 4 \
calculations are given to the nearest 0.000l*C, although 3%7 9
the measurements were made to only 0.00!*C, to cc i m,,,c3 g,v,,i I ;
]
lacilitate conversion. ,_
- 0.01
- 0.002 Om 0.05 0.000
! III. EQUATION DEVELOPMENT 0.2 0.000
- 0.001 0.000 I 0.5 - 0.001 30 0.004 To ascertaan whether these two data sets are compat. +0N ON ible, separate least-squares 6ts were made* at the l
Naval Undersea Research and Development Center 2S 30 NEOm j
t (NAVUSEARANDCEN). A 6fth-degree polynomial was found satisfactory for both, vis:
jj "p g
0 002 1 4.0 -e 0.002 4.2 0.002 s
- 0.002 0.002 2 4.5 - 0.004 33 0.002
- C = T., 4.T** (1) -08 08 4
' 6.0 -0003 0.004 8.0 - 0.003 0.004 10.0 - 0.001 0.004 j The 36 earher observations in Table H over the #.0 - 0.004 Om i
temperature range 0.056*CSTm574.022*C were 6t $j Q $$
with a standard deviation of 0.0025 m/sec and coedE- 90.0 - 0.004 cients as given in the third column of Table HI. Omo 95.0 em Om The least. squares 6t to the 112 data points of Table I nest 6ais set over the larger temperature range 0.001* CST. 0.06 g.001 0.006
$95.126*C, but with empbams between 0* av 10*C 5.0 - 0 001 0.006 has a standard deviation of 0.0026 m/t able a-E==ts as given in column two e . anne IH.
. s .npar- $j "gp $$
25.0 +0.002 0.000 Because of the close agreement between these expres-siens, Tables I and II were <=d==arl, and a least-jj m.0
- 0.001 jg squares it was obtaaned to all 143 observaticas with a 0.002 50.0 0.000 0.002 standard deviation of 0.0029 m/see and coedEdents as given in the last column of Table IH.
$j 4j$ $$
Tansa VI. Tamperature scale conversion.
To To TcTe To To TrTo To
(*Q (*C) To Te-Te To To TcTe
(*Q (*C) (*C) (*Q (*Q (*Q (*C) (*Q (*Q (*Q 0 0 0 26 25.9913 0.0087 51 50.9097 0.0103 76 75.9932 0.0048 1 0.9995 0.0005 27 26.9911 0.0009 52 2 51.9097 0.0103 77 76.9934 0.0006 1.9990 0.0010 28 27.9909 0.0001 53 3 52.9098 0.0102 78 77.9937 0.0063 2.9906 0.0014 29 28.9005 0.0092 54 4 53.9999 0.0101 79 78.9939 0.0061 3.9901 0.0019 30 29.9007 0.0093 55 i 5 54.9099 0.0101 30 79.9961 0.0039 4.9977 0.0023 31 30.9005 0.0095 56 6 55.9900 0.0100 81 80.9944 0.0056 5.9973 0.0027 32 31.9904 0.0006 57 7 56.9901 0.0099 82 81.9M6 0.0054 6.9999 0.0031 33 J2.9902 0.0008 58 8 57.9002 0.0008 83 82.9M9 0.0051 7.9965 0.0035 34 33.9901 0.0099 39 9 58.9003 0.0097 M 83.9952 0.0048 8.9961 0.0039 35 34.9900 0.0100 60 10 39.9904 0.0006 85 M.99H 0.0046 9.9957 0.0043 36 35.9999 0.0101 61 11 60.9906 0.00M 86 85.9957 0.0043 10.9953 0.0047 37 36.9098 0.0102 62 12 61.9907 0.0093 87 86.9960 0.0040 11.9950 0.00$0 38 37.9098 0.0102 63 13 62.9908 0.0092 as 87.9963 0 0037 12.9946 0.0054 39 38.9007 0.0103 64 14 63.9910 0.0000 09 88.9965 0.0035 13.9943 0.0057 40 39.9097 65 15 0.01(t3 64.9911 0.0009 90 09.9968 0.0032 14.9940 0.0000 41 40.9096 0.0104 66 16 65.9913 0.0087 91 90.9971 0.0029 15.9937 0.0063 42 41.9096 0.0104 67 17 66.9914 0.0006 92 91.9974 0.0026 16.99M 0.0006 43 42.9096 0.0104 6B 18 67.9916 0.0004 93 92.9977 0.0023 17.9931 0.0069 44 43.9095 0.0105 69 19 68.9918 0.0082 94 93.9981 0.0019 18.9929 0.0071 45 44.9095 0.0105 70 20 69 9920 0.0000 95 94.9984 0.0016 19.9926 0.0074 46 45.9095 0.0105 71 70.9922 0.0078 96 95.9987 0.0013 21 20.9924 0.0076 47 46.9095 - 0.0105 72 71.9923 0.0077 97 96.9990 0.0010 22 21.9921 0.0079 48 47.9906 0.0104 73 72.9925 0.0075 98 97.9993 23 22.9919 0.0081 49 0.0007 48.9096 0.0104 74 7J.9928 0.0072 99 24 23.9917 0.0083 98.9997 0.0003 50 49.9096 0.0104 75 74.9930 0.0070 25 24.9915 100 100.0000 0 0.0055 The J met of ete Aes seisel 5.c.ny of A ace 1445
l u
DEL G ROSSO AND MADER m
This equation st to the combined data predicts a precision (standard deviation dve times larger) and
[h \ sound. speed madmurn of 1553.147 m/see at a tempera-ture of 74.172*C on the T scale. Sound speeds cal. greater scatter (twenty times larger) where relatig culated with chase coetlicients are given in Table IV measurements over a smaller temperature rang for tenthy celsius intervals. A rounding off of (6*CS Tf 81*C) showed "no signiscant discontinuities.
thm co.dioents is employed at NAVUSEARAND. or other anomalous behavior." These latter aut%
fcund an eighth-order polynomial was required to fit CEN for velocimeter calibrations.*
their data, and they ignored a deviation three t%., l greater than their scatter, IV. DISCUSSION OF RESTJLTS l In light of the above, this present data is presented.l The standard deviation of the equation fit to the simply as the most precise and hopefully accurau' data is 0.003 m/see or 2 ppm. As stated, the measure. values of sound speed in pure water.
. 9 ments are most probably accurate to 0.015 m/sec. A temperature scale conversion table is presented in i l Another measure of the precision of the data (p Table VI to assist those still operating on the T.: scale, from accuracy) in the form of reproducibility over replications can be obtained from Table V, which lists the average regression deviation and scatter thereof, pNikr[O'""* * l' A'*"'*- ^" I'*
for nominal experimental temperatures. It is tempting l
' V. A. Del Groeno, J. Acoust. Soc. Amer.47,947-049 (1970). j to postulate the existence of anomalies not only about .' VV.^ A.
D'8Del G *- ^'*"'t. Soc. Amer. 48, 770-771 (1970).
G'rosso,1 4*C but also at 40* and 90.C, but such an assertion is Acusucs 24,299-Jll (1971). 1
- t. V. Mma===, pavate comunicatan Uanuary 1971).
strongly resisted since the deviations are of the order of
- K. V. MM- . pnvate communicanoe (Fet>ruary 1971), l the scatter and standard deviation. Comparison of the
^3'" d ,^**" M'^MM333[1)'E % J~
preent results may be made to other work' of lesser Chem. Phys. ,25G-2543 (1969). , .
l 1
1 v
O V 1446 Ven =a 52 N.-n.,5 trere 2) 1972 l
l
i Bubble Growth by Diffusion in an 11-kHz wund Field ANTaowy I. Enza I
Neuel tempedmeas Scheel. huerry. Cdifornie PJoe (Recoved 20 Apest 1972)
- Bubble greerth by rect
- 6ed difumon of gas was imensured for angle bubbles in an 11 Idia underwater sound 6mid. Observed results are compared to calculated results for ===d i seetherusal or adiabatic puleauens i of the bubbles. The calculated threshold for growth is cosastant wuh observations. but the cniculated tunes of growth escoed the cheerved tunes by factors of about 10-100.
l Susiser Cz.nastricAriow: 13.8.
I-I i
l This paper reports measurements of bubble growth roults are presented in Fig.1. The symbol X indicata I ay recti 6ed diffunion in an 11-kHz underwater sound the values of peak sound pressure amplitude an 6 eld. Bubble radii ranged from about 50m to greater I than 200m, and peak acoustic pressures ranged up to radius for bubbles that grew smaller and, about 0.3 bar. The roults are compared to predictions below thrabold. The symbol O indicate bubi itheory. grew larger; they were above the threshold. The solid i curve are calculated thraholds for mothermal and I hreshold conditions for growth, and the subsequent adiabatic pulsations of the bubble. Thee curve were '
rates of growth, were previously reported for a sound calculated from Eq. 8, which is derived later. The frequency of 26.6 kHz.* The present roults extend the adambatic threshold curve is consistent with the observa-arevious study to a lowerufreq' ency and were obtained tions, and, with a few excepuans, this curve separ ay a procedure aimdar to that decribed in Ref.1.
the conditions for growing and dissolving bubble.
The experiments were conducted with air bubbles in In a review of the thermal propertie of pulsating ses dr saturated water in a vertical 6-in.. diam Pyrex pipe, bubbles, Devm8 dennes a parameter a that indicates the driven by a transducer at the bottom. The water column proximity of the bubble motion to isothermal or adia.
was 43 cm high and resonated at 11.08 kHz. The water batic behavior. Values of y/a range from 1, for an l mrface at the top and the glass walls were approximate isothermal process, to 1.4, for an adiabatic process in aressure-release surfaces. Individual air bubble were which the ratio of speci6c heats y is 1.4. For the experi-acoustically trapped near a pressure antinode located mental conditions, computed values of v/a range from 2ne quarter wavelength, about 4.6 cm, below the sur. 1.07, for a bubble radius of 50s, to 1.27, for a bubble face. Bubble size was monitored by means of rise-time radius of 150 u. Thus, Devin's pararneter indicate that measurements at regular time intervals. The acoustic the experunental bubble fall between isothermal and l oressure was monitored with a alibrated hydrophone. adiabatic behavix, with smaller bubbles closer to After each set of measurements, the pressure ampli. isothermal conditions and larger bubbles closer to tude at the bubble was calculated through knowledge adambauc.
1 of the bubble and hydrophone locations and the geome. In a second series of experunents, the acoustic pre-try of the sound 6eid. De bubble radius R was com. sure amplitude was held constant at 0.25 bar. The puted from the rise velocity a by iterating the following growth of a single bubble located near the presure l approximate equation from Langmuir and Blodgett% antinode was mesu,tored by means of frequent rise-time measurements. Seventeen different bubble were ob-l R'= (9r/2g)s[1+0.197(2Ru/r)' *8], (1) served, and the data were used to compute the average time required for a bubble to grow from selected values where e is the kinematic viscosity of water at the ap- of initial and 6nal radius. The observed average times propriate temperature, and g is the gravitational of growth are presented in Table I and compared to acceleration.
calculated times of growth during isothermal and adia.
During one series of expenmental runs, the sound batic pulsations. The observed times are considerably i
pressure was continually adjusted to bring it close to shorter than the calculated time. Bubble radii were ob-the threshold for growth of the bubble present. The served to increase from 120 to 180u, for example, in 3 n. m ., r.e - rr ., a.a i4g7
Received : Dnember 1968 10.0
(
Echo Phase-Comparison Technique and Measurement of Sound Velocity in Water I
i R. C. Wtr.t.tausow i
. VASA Becarenses Rssearch Camer, C.nnaredu. Massecluumts 02130 A technique is described in which the ultrasonic time delay between successave echoes m an echo tram deterrassed by phase comparison of the echoes with a coherent enouaucus sienal. Correcuoos for phas of an echo upon redecuan from the face of a trea*=r and for difracuan edects are d>=runand The veiecev of sound at 1 MHz in dasuDed water kom 23' to 75'C has been maneured with this technique. Measurem of tinie delay agreement are aa:
with values urate in the to 20 literature ppm while the over.all accuracy is 127 ppm er *0.20 m/sec. Excellen:
is found.
4 l
L DtTRODUCTION with umilar measurements by McSkimmint8 and other Ultrasonic pulse techniques for the measurement of authors who used diferent tedmiques.
sound velocity in solids and Suids have become weu developed in recent years. For ultimate accuracy and g mg, sensitivity, these techniques must measure time delays with a resolution much smaller than one cycle of the A. Standard Phase-Comparison Technique 4
v carner frequency. His usually mvolves some type of Before describing the manner in which the phase-Phase cocupanson. Ultrasonic delays see determmed by , 9 g, comparmg the phase of an echo in an echo train with of absolute velocity, a general description of the tech-that d another echo ** or with a coherent contmuous nique in ts usual form is in order. A block daagram of wave at the carrier frequency.* ,It is the purpose of g y ,. .
m Fi h
- M@
this paper to present an application d a standard generator is fed through a gated ampliner to provide 4
phase.coenpanson techmque d the latter type (phase- a busit, which excite the transmitting transducer. De sensitive detection or homodyne technique) to measure- signal generated in the receiving transducer (or in the ment of the absolute velocity d sound. De necessary dual purpose transmitting transducer) oy the train d corrections for difraction and for phase shift of a pulse echoes bouncing back and forth between the trans-on redection are dium==d. Data on sound velocity ducers is amplined and mixed in the phase detector (mixer) with a continuous reference signal from the in distilled water are given and compared in detail signal generator.
By means of a variable delay line the phase of the
$ g, a H. h. McSkimmin. J. Acoun. Soc. Amer. 33,12-16 C MI). 'I'UC' 8 gnd can M placd in quhture M de
, p p.a.ba J. .wusc. Soc. Anmer. 42.1045-1051 t1967),
' H. J. McSkissaa.J. Aeous. Soc. Asser.29.1185-1192 fl956).
received signal of a chosen echo thus giv ng a null Williams and J. Lama, J. bust. Soc. Amer. 30 J00-313 output from the phase detector during the receipt of NP. Espinona and P. C. Watermaa. J. Appt. Phys. that echo.
- 29. As the ultrasonic delay changes, the settmg 4
718-721 11958). of the delay line can be changed to maintasa the null
- W, Schaars and C. Kalweit. Acusuca 10. 385-393 (1960). condition. Changes of delav-line settings are thus equal
' R. W. Leonato aan H. 3ceuta. J. Acoun. 3ac. Amer.10 to changes in delay or.t he ultrasonic signal.3,, .yter-1467-l472 (1966).
' R. J. Dlume, Rev. Sci. Instrum. 34. 1400-1407 1963). nately, the frequency of the signal generator can be
' C. E. Chaw. Phys. Finads 1.19b200 i1958).
Varied to maintain a null condition.7 Because these are
- W. M. Whitnev and C. E. Chase. Phys. Rev. 158. 200-214 null techniques. : hey can be maae extremew tensitive i1967).
- 4 R. C. Williasnson and C. E. Chase. Phys. Rev. 176.235-194
,1968).
2 H. J. McAimmin. J Acoust. Acc. amer. a ;23- 623 . IM
- Q Y %eernes of the acoustices ec,ety or amence 1251 1
. ..- .. - ~ - .-. - - - . _ - _ . . - . ~ - - - - . . - . ~ . . - . - - ~ ~ . - . . . . ~ . . - . . ~ ~ . ~ . ~ - . - .
I t
.R, C W I L 1. I A il S O N .
l
[\ reeGoes t semenaron -
ULT 44sosesc i efatose 'ga g,ggn r i sle888b O'IU l0 ggesemaf04 - e geput d M IEA aaspLFem FIG.1. SchemataC dia.
-O gram of ultrasonic phase.
TAaNateTTsus neceNuss ! Companson Ortuttty.
rAases0uCE A r#aNseuCeR osca.LosCoPC l
u ..,4ea -
1 oeLav stesse ,
L388e oeTecton l o _
to small phase shif ts. Sensitivities of 10-8 sienal periods are routinely obtainable and, with an ultrasonic path the signal generator (Fig.1) is applied to the t containing 108 wavelengths, this results in an over-all mitting transducer, a series of echoes will be detect by the receiving transducer. The frequency of the sensitivity In situat @ ions where high attenuation , .
exists signal generator and the phase phase of the reference can be comparison techniques have another distinct advantage adjusted until the reference signal is simu over other velocity-measurement schemes. He circuit quadrature with the received signal during all of the echoes. His condition is shown in Fig. 2. When the shown in Fig.1 is essentially that of a phase sensitive reference and received signals are m coherent detector. By using a boxcar integrator at the detector, a null output will result for eve phase <ietector output gated on a particular echo p (usually the Arst when high attenuation exisu), it is for this " null condition" we can say t
possible to measure ultrasonic delay and attenuation a
even when the signal is buried in receiver noise.'8 T" " r " ~. (1)
With all the advantages of the phase.companson /
technique enumerated above, the standard application of the techm9ue has been of limited usefulness because where T is the time delay it is capable of measurmg only changes ta ultrasome integer; and ed r= l/f, the of carn.er pen.between e frequency. .
delay caused by a sides changes in' expenmental ps. ne values of f that satisfy Eq. I are referred to as rameters, e.g. temperature or pressure. With the tech. o,,33g,,q,,,,5,,,o nique described above, it is not possible to measure By obtaininE this null condition for a series of the total ultrasonic delay across a timed path and values of s, it is possible to determine the v,3ue gor thereby determine the absolute sound velocity.
~ a for any given null frequency and thus to determine
.The technique described in this paper is a means of TM From the value of T and the path length between using the standard circuit shown in Fig. I to measure the transducer faces d, the ultresonic velocity u can be the velocity of sound to high accuracy. As is shown, determined:
the techmque is competitive with any existing means == 24/T'= 2df/s, for the accurate measurements of absolute sound ve' locity and is simultaneously able to exploit the unique T' = tn.TaAsONtC DEtM = I. (2) t capabilities of phase. sensitive detection for measure-ment of small velocit) changes and highly attenuated The small corrections, which are applied to the mea.
l signals. sured delay T in order to obtain the ultrasonic delay T', are discussed later.
B. Echo Phase Comparison Techniqu*
Let us examme. more ;enerally, the form of the phase-detector output for arbitrary frequencies. The Consider the arrangement of transducers and speci, output E of a balanced mixer (phase detector) is pro.
men shown in Fig. 2. When a short burst gated from is in musuons where it is not possiWe to mee maaur**ea $
u R. C. Willismasa. " Measurement of the Velectv and Attenu. over a sudoently mde ranse of frequencies to oeternune 'i. '4 i auen of Cittaasaec Pulsen in the Presence at . Noise," Rev. .sa. iess accurate value for the souno ve6ooty may he ootaanen from Instrum. 40.670-674 419e9). is=2das/as.
I 1252 veissae 45 N==iber 5 1969 L
i
_ _ . . , . _ _ - , ._- ~ _ _ _ _ _ _ _ ____ m ___ _.
I SOUND VELOCITY IN WATER
- -TR&xsoucEns.=
?
', speciangh r ,
'/
slG8 sal 18s *-
/==* stGmaL out
~ - ~ -4 i sr nr Fic. 2. Schemauc dia. EcMo I gram illustrating the phase relationskaps of Ecwo 2 the receved and refer.
y$
, , geno 3 ence signals for a null sectWEO ^ I E0"O "
stessat j l l' condition. . . l - * **
- M-I,d! I I 7 --=ii l
. i j ,l 1 ; ; ; ;
i au ratact i sisan . ....
l r l_.
l portional to the amplitude of the received signal and for ultrasonic transmission through water at f= 1 M
! a sinusoidal function of the phase difference 8 between for various values of f and e. The damped sinusoidal the references and the received signals. For the 4th form of the output predicted by Eq. 8 is evident.
received echo with amplitude A.,
! The accuracy with which null frequencies can be l E.= J sm, d.. determined depends on the precision with which the (3) phase of echoes far out in the echo train can be re.
The time delay and amplitude of the kth echo are solved. This in turn depends on the attenuation con-j given b}.a stant a, the noise level m the sptem, how well the phase within each echo is defined, the capabilities of l
T.= (4- )T-(&-})/f. (4) the phase detector, and the number of wavelengths in t a , . 3,,-w.-u o e#f[$) the ultrasonic path. As a result, the precision varies I
% g. considerably from one experiment to another. How-where a is the attenuation cons 'a'n' _' yd k the echo ever, a general idea of the considerations involved
!. number. Therefore,
/
V, be obtained from the following example, which ap-
! proximately corresponds to the measurements in dis-l=
E.= A c-2d*-D sin (2H(4-})f/f.++). (6) tilled water that are discussed later.
The difference in electncal delay between the reference Consider the situation in which the phase difference and signal paths (Fig.1), meluding delay in the delay between the lith echo in an echo train and the refer-line, is absorbed in the phase angle d. ence signal can be resolved to within 10-8 signal periods When e is adjusted to 0* or 180* (with the variable v. Further echoes are discarded since the resolution of delay-line), E. is zero for all echoes (all k's), when- their phase rapidly deteriorates owing to increased ever f= af, and n an integer. This is the null condition. attenuation. If the 'round trip delay between successive In pracuce, the delay line must be adjusted slightly echoes is 108 r, the delay between the first and lith j
to obtain nulls at different values of rs because phase echo is 108r. Therefore, the over all time (or frequencv) ~
shifts that occur in the electronics and in the acoustical resolution is 10-' r out of 108 r or 10 ppm.
coupling change with frequency. Although the time delay between any two selected When / is not an integer multiple of f., we can wn. te echoes in an echo train can be measured as described above, the null frequencies are actually determined by f= (n+x)f , izi < } (~) viewint 2n over all scePe display described bv Eq. 8,
- and not by careful attention to any given patr or echoes.
I It is, therefore, instructive to view, in an .titernate E.= J ea-8*'*-H4 sin (2H(A-t):+e). (8)
I way, the precision with which the null frequencies can In this case, the phase detector output is a damped be determined. The smallest value of x that can be sinusoidal function of the echo number k with penod resolved,3x, is reached when x, the frequener of the equal to lix. Figure 3 shows the phase <ietector output ciamped oscillation, becomes small compared to the damping rate 2ad The fractional resolution in null a For the situauon in which univ one transducer is used as both frequency or time delay is 6xin (see Eq. 7). Note that tra mit recener, a snousd be sutioututec tor k -tf in at the crossover pomt where is= lad, the resolution O The Jemmet of the Acesstical $ecety of Americe 1253
R. C. WILLI AMSON (a) 3)
(c)
' 4 o'. -
${?r~' -- .t ll
-.w 59 er e < -
,_,,w
,,e .
i Fic. 3. (a) Unrecti6ed echo traan trans rutted through water: Ibi phase
..-- detector output for ,
. = 70.100 f s., . .._ ..-
'ure.m~ e = 180* in Eq. 6 of the text; ics sarne (or j = 70.010 f., e = 180*; td) same
':,,e*** for t = 70.000 i., e = 180* tel same for 'f = 70.000 ., e = -00*. Total
- 8 sweep length is mecc in all cases.
(4)
(e) wavelength in the sample and Q the mechanical quality of the sample. In our examp,le,2ad=10-8 or 180*, whenever (a) lZlKl2,l; (b) l2l>>l2.1; or therefore, resolution is limited to values of x of andthe (c) Z a real number.
order of 10-8. He value of n in Eq. 7 is about 100 ne technique for minimimag y for measurements in (number of signal periods in one round trip delay) and solids has been discussed by several authors.'-* For the over-all frequency resolution is therefore 10 ppm, solids, the characteristic impedance of the transducer as obtained previously. material Zr is often close to Zs. In this case, the object is to approach Condition a by operating the trans-C. Corrections for Phase Shift upon Redection ducers at resonance since in the ideal case where efects of bonds and electricalloading are neglected, The timewielay T between successive echoes in an echo train differs from the ultrasonic delay T=2d/s, Z= iZr tanHf/f,, (11) whenever a nonzero phase shift, y, occurs upon redec-tion at a transducer-sample interface. For a two. and Z goes to zero when the signal frequency / is transducer arrangement (two identical reflections in equal to the resonant frequency f each round trip) For measurements in fluids, Condition c can be ob- '
tained by the use of bufer rods." his technique has T-T= 2(7/2II)(1/f), the disadvantage of limiting the length of the echo or train, which may be examined before unwanted echoes interfere.
fr-s = 2(y/20). (9) A simple alternate to the use of buKer rods is de-herefore, in order to obtain T from the measured T, scribed here. Since 2, for most duid-transducer com-it is necessary to calculate y accurately or to arrange binations is smaller than Zr, the attainment of Con-the experimental apparatus to make y as close to O' dition b is suggested. Consider an open<ircuited, or 180* as possible. In practice, the latter course is lossless transducer with resonant frequency f,imrnersed usually chosen. in a Buid medium of impedance 23. In this case, the he reflection coefEcient r at a transducer-sarnple input impedance 2 for a planar acoustic wave incident interface is given by or. the transducer is n
r= f rle = (2-2 )/(Z+2.) (for pressures), (10) iZr sinD/'f,+2. cosII///,"
Z = Zr (12) where Z is the acoustic input impedance to the trans. .Zr costif!f,+sZs ssnnl'f..
ducer assembly (including efects of electrical loadint.
bonding materials and backings, when present) and Under the assumptions 2,<2r and .1///'K1. where
- 2. is the acoustic impedance of the specimen (usually f'=f,/2 and of=f-f', y in Eq.10 is given by:
assumed to be pure real). According to Eq.10, y=0*
y/2TI=-QMaf/f'MZy2). 7 '13) 1254 Veleme 45 Nember 5 1969
s o t! N D VELOCITY IN WATER p At M-0, y=0*. .tnd the transducer is operating as a distilled water specimen. The temperature of the bath quarter wave termination with inrinite input impe.
dance. This is the technique that was used in the mea. was read on a -1* to 101*C (0.1*C division) mercury
(~ in glass thermometer supplied with the National Bureau surements of sound velocity in distilled water. which of Standards certiscation. When fully immersed, the are described in this paper.
indicated thermometer corrections usually amounted to less than 0.03*C. At the higher temperatures.
IL SOUND VELOCITY IN DISTILLED WATER emergent stem corrections of as much as 0.2*C were A. Introduction N Distilled water provides a good specimen for testing Memod and comparison of different sound velocity measure. At a few temperatures. null conditions were obtained ment techniques. Water is stable, readily available, for a series of frequencies above and below 1 MHz.
has fairly constant acoustic properties and is relatively By making such measurements over a surficiettly wide unadected by impurities, particularly dissolved air.is range of frequencies, it was possible to determine un.
Many measurements of sound velocity in water have ambiguously the proper value of n for each null fre-been made and good data exist in the literature with quency (Eq. 2). At each temperature, the delay T which to make comparisons. However, as Greenspan" was calculated for each of the null frequencies (Eq.1).
and McSkimminu have pointed out, considerable dis. The values -f T obtained in this way difered by a agreement exists between quoted values of absolute small amount due to the frequency. dependent phase velocitv. McSkimmin has made a study of the absolute shift 7 predicted by Eq. 9. The value of T at 1 MHz, soundv ' elocity with a technique of high absolute accu. half the resonant frequency, was assumed to be equa racy and his values therefore provide a good standard to the ultrasonic delay T'since Eq.13 implies y=0 of comparison. As is shown later, our values for sound at this frequency. Representative data at a tempera.
velocity agree quite well with those of Mc5kimmin.
" ture of 25'C are presented in Table I.
The third column of Table I represents the phase B. Experimental Apparatus shift upon reflection as obtained from Eq. 9, where T*
The electronic circuit used is basically the same as is the ultrasonic delay computed for f=1 MHz bv that shown in Fig.1. For case in setting and measuring intespolation between the values of T computed a frequency, a frequency synthesizer was used as the null fr quencica. The quantity t/2II should vary ac.
O signal *tnerator. The phase detector was a modified cording to Eq.13. However, the data in Column 3 Q have a slope versus frequency approximatelv twice as AC-D: converter.58 A diode switch followed by a large as the predicted value. This result is' probably power ampli6er served as the gated amplifier. The remainder of the circuit was composed of standard due to electrical and mechanical loading eHects on the commercial components- transducer, which are not accounted for in Eq. 9.
The ultrasonic transducers were two 1.in. diam z. cut, More important, such efects may cause the frequenc at which y=0 to shift away from 1 MHz. If we make quartz c:ystals, resonant at 2 MHz. These crystals the assumption that the frequency at which t=0 is were fully plated on both sides and spring loaded within 2% of 1 MHz, we can use the slope of the against opposite ends of an accurately truchined brass data in Column 3 to estimate the possible error intro.
spacer. The length of the spacer at room temperature
(=25'C) was measured with a micrometer. Several 7, t y measu'ements were made around the circumference of , ,g g,,,,g ,,% 3 water at 25.00*C.
the spacer, and were averaged to compute the path length d= 3.1517*0.0004 cm. The spacer was con-Number of structed such that the region surrounding the ultra. I'requency waveiengths g'-= (Ref. as sonic path contained no solid material except foi two
- P"""""'"' O d * *F*
narrow brass posts, which supported the opposing o.90103 62 11 transducer holders with respect to each other. By placing these supporting posts about I cm beyond the M
0 94453 d
63 O
1.2 outside edges of the transducers. the ultrasonic path was essentially free of obstructions and the sound Q 09s79 j y propagation was free 6 eld. ns 03 1.00246 w -o1 The transducer assembly was .lirectly immersed in a temperature-controlled water bath nlled with the [$
1.04589
[0 72
~_M
- 1.1
.06Q37 73 -13 a M. Greensosn .uw C. E. Tsctuea. J. Acoust. Soc. Anwr.
- 23. 301 (1956L
" M. Greenspan. J. Acoust. Soc. Arner. 31. 347fM t 1959L Ih g $ Nf
' raanc .wa.utements rnooet iuos. - u.
V l
rw2 ...,w u.or... s.<,,,. a . 1255 l
R. C, W1 LL1 A MSON T4sts !!. (lncertainties.
' of T4sts III. Velacity ai sound in .hstilleo nater as .s iuncimn temperature Quantity (lncertaanty (*ncertainty Tj m velocny i"A T emperatu re Velocity a iRef. as t*C1 i m sec s Temperature .m sect me.al*C (23*C1 =0.0033 22.97 20.04*C (30*C) 2 0.0032 149 07 o as 23.98 1493.37
- 0.03*C (73*C) 3 0.0000 23.00 0.0 L Path length 30.0004 cm 1496 63 0.00 Thermal espaansen
- 0.0000 26.01
- 0.0000 cm (23*C) - a0.0000 1499.29 0.06 26.97 I501.70
- 0.0001 cm (30*C) 3 0.0023 28.00 Om 20.0002 cm (73*C) *0.0059 1304.31 0.02 Frequency 29.00 1306.71
- 20 Ha at 1 MHs 3 0.0020 30.00 - 0.01 Phans sh:it 30.004 cycles *0.0037 1309.10 - 0.07 redaction 33.00 1319.83 40.00 Om Di 'on ' 1328.92 0.09 3 0.0030 45.00 Over-eal *0.20 m/sse tall T) 1536.42 0.03 2 0.0127 30.00 1342.36 - 0.01 33.00 1347.41 0.03 60.00 t35t.t3 o.17 63.04 1333 6t O.19 duced by a nonsero r at 1 MHa. The resultmg un.
70 00 1334 90 0.00 73.JO certainty is *0.004 cycles. 74.00 1333.22 0.13 1333.30 0.21 Once a for each null frequency has been determined '73.00 1333.30 0.22 at a given temperature,it is not necessary to repeat the 1 whole procedure at nearby temperatures if the change 'C**"""**""""'8""' !
in sound velocity is sufliciently small. Over most of the temperature range, measurements were made only for a It should be noted that the frequency of 1 MHz small range of frequencies close to 1 MHz and the value used in these measurements is much lowe of werethe ultrasonic interpolated fromdelay and sound velocity at 1 MHa frequencies normally used in ultrasonic pulse these measurements.
The final value for the sound velocity was obtained ments. If, for example, a frequency of 30 MHz were by applying a correction for the thermal espansion of used, the number of wavelengths in a round trip (e in Eq. 7) would be 30 times as large and the corre-brass (17 ppe/*C) and for efects of diffraction. The 7ponding accuracy would be 30 times greater. I magnitude of the d4 fraction correction for each scho tion, diffraction efects would be much smaller. How-I was by Mar coenputed 4iminin." Bevond from the thethirdequationsecho, this and correc-empirical study ever, the increased accuracy obtainable by g tion was relatively constant at -(1.8*0.5)X10-* for higher frequencies is limited by the correspondingly ;
all visible echoes. Therefore, when determining the higher attenuation, which limits the number of frequencies for the best null conditions, the first two echoes. More fundamentally, it is diflicult with any technique at any frequency to obtain a velocity resolu-or three echoes were ignored and a constant correction tion much les than the inverse of the mechanical wea applied for all the maining echoes.
giality of the sample.
D. Uncertainties E. Results The major sources al ;.oenible error in this experunent Table III shows the data obtained in this experiment are listed in Table II. As can be seen from the Table, over the temperature range from 23' to 75*C These the largest source of error is uncertainty in the path data are compared with the values obtained by in length and in the correction for thermal awpaa=iaa. polation from the data of McSkimmin,'8 whme values The values listed for thermal espan=an and difraction are lower than those listed by ! . Excellent agreem in Table 11 are the uncertainties in the magnitude of obtained up to 35*C. Above this temperature, th the correction to the measured sound velocity and are not equal to the ma6nitude of the corrections them- rnent is not as good, but a remains within the d combined selves. The fact that the uncertainty in frequency is uncertainties of our measurements QI:Skimmin :
- 0.10 m/ sec, this work: 0.20 m/ sec). These messure-among the anallant in Table II indicates that the echo ments confirm the accuracy of McSkimmin's resu!ts phase-companson technique has capabilities for men- and indicate the accuracy and usefulness o suring time delays that have not been fully exploited phase. comparison technique.
in these measurements. The over.all uncertamty of Recently, very accurate measurements of' sound ve-
- 0.013% or *0.20 misec is computed by treating all locity in water have been made by Carnvale es d at values in Table II as random errors.
the Naval Oceanographic OHice.* Our data over:ap
- H.
(1900). J. McSkimaan. J. Acoust. Soc. Amer. 32. 1401-1404
- A. Caravale. P. Bowen. M. Baadeo. and J. Speanke. J.
4coust. Sec. Amer. 44, 1095-1102 (190s).
1256 vei==e 45 Nember$ 1969
l
$0UND V E L. 0 C I T Y ~ fN WATER l theirs at four points. 25*. 30', 35' and 40*C. The
~
[ h measurements except those of Greenspan and Tschie::gd differences in the sound velocities that we meaure are and Wilson,u whose values for velocity lie c
(% ~
(this work-NAVOCEANO): -0.04, +0.04. +0.10. higher than ours.
and +0.10 m sec,respectively. Again, agreement within the stated accursey is obtained. ACENOW1.EDGMENTS A comprehensive companson with other data in the The author is grateful for the hospitality of the literature can be made by referring to Refs.12 and 21. Center for Materials Science and Engineering, MIT.
Our data agree quite well with all of the most accurate where this research was perfonned while the author was a research affiliate.
! m R. A. McConnell and W. F. Mruk, J. Acoust. Soc. Anwr. . 31." 75-76 M. Greenean (1959L and C. E. Tscluess. J. Acount. Soc. Arnet.
27, 672-676 (1933).
I
- W. D. Wilson. J. Acoust. Soc. An,c . 31. 1067-1072 (19391 I
o _ . _ ..,r. _ . w ,... _ . m,
I Responses and Further Clarificnions to NRC Questions from September 29,1998 Meeting l 6. Grosso, V. and Mader, C.," Speed of Sound in Pure Water," Journal of the Acoustical l- Society of America. 52:51972.
! 7. Williamson, R.," Echo Phase-Cor.iparison Technique and Measurement of Sound Velocity in Water," Journal of the Acoustical Society of America. 45:5, May Additional ClariGcation Requested:
None.
f
(
i I
i
'O 2 ,
. . . . . . . - . . . - . . . - - - , ~ . . ~ . . . . . . - . . - - . - - . ~ . . . - . - . . . . - - . - . ~
Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting Question 15:
I Explain "non-fluid time delay".
l - Answer:
l l 1 The "non fluid time delay" is the portion of the total trc.nsit time measured by the )
LEFM/ which is not spent in the feedwater. [ i I
Attachments:
1
'l. [ ]
Additional Clarification Requested:
None.
I 1
. , ~ . . ..- .....-...~ .. - . _ . - - . - - . . , . - -
. . .- - - - - . - . . - . - . - - . . . ~
i Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting
'l Question 16:
- y-lf i
.What is the transducer firing sequence?
Answer:
b~
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l Attachments:
- 1. Figure 16.1. Chordal LEFM Acoustic Paths Additional Clarification Requested:
None.
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Figure 16.1. Chordal LEFM Acoustic Paths v
O
. _ . . _ . _ . . _ _ . - _ . . _ _ _ . . _ _ . . , _ . . . _ . = _ _ _ . . _ . . _ _ _ . . _ . _ _ _ . . _ . . . . _ _ _ _ _ _ _ . . _ . _ _ . _ _ _ _ _ . . .
Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting Question 17: l Reference page D-13 of the Topical Report. Is the spool piece alignment uncertainty [ ]
Answer:
Spool piece alignment uncertainty is assumed to be [ jas accounted in Appendix E.
I l 1 l
Attachments:
1.' [ ]
Additional Clarification Requested:
None.
O O ,
l l i
Responses and Further Clarific tions to NRC Questions from September 29,1998 Meeting j l
l l Questica 18:
o i Reference D-14 of Topical Repon. Explain the [on-! -e measurement lof the non-fluid l('
\
time delay.-
l l
Answer: l l
l The "non-fluid time delay" is the portion of the total transit time measured by the l LEFM/ that is no' tspent in the feedwater. [
l l
I l Attachmentt: ;
None.
Additional Clarification Requested:
Add long path and short path definition.
Answer: l
/m b The LEFM has four acoustic paths, located such that they are weighted by factors unique to Gaussian quadrature numerical integration (Handbook ofMathematical Functions With Formulas, Graphs and Mathematical Tables, Abramowitz & Stegan, National Bureau of Standards Applied Mathematics Series 55). This path configuration is as follows, where paths 1 and 4 are the short paths, m
'p' Q,/ '
,-', .o
,, / - ,- ,,-f,%'.N3
. D DD D
,/ ,# ,/
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p -.
! Responses and Further Clarifications to NRC Questions from Sept:mber 29,1998 Meeting l
i Question 19:
Reference page E-14. Explain how [ profile factor] uncertainty can be bounded for a spool piece that has not been calibrated at a hydraulic lab.
Answer:
I 1 1
Note: This answer, the answer to the additional clarification request, and all attachanents are proprietary to Caldon Inc.
l
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[T Respons:s and Furth r Clarificttions to NRC Questions from September 29,1998 Meeting Question 20:
Reference Table E-1 of the Topical Report Explain how reference to ISA RP67.04 applies.
Answer:
. The calorimetric power uncertainty presented in Table E-1 was calculated in accordance with ASME PTC 19.1 - 1985, ISA RP67.04 is a guidance document for calculation ofinstrument ~
. uncertainties in the context of safety-related setpoint calculations. Since it applies to safety-related applications, ISA RP67.04 does not directly apply to the determination of thermal power.
However, the recommended practice was consulted during the calculations included in the Topical Report since it is an example of good practice. Both ASME PTC-19.1 and ISA RP67.04 state that the root sum square ofindividual error contributors is appropriate for independent contributors provided the errors are uniformly distributed and there is no single dominant ;
uncertainty. [ !
(
l Attachments:
1
- 1. [ ] j Additional Clarification Requested:
None.
1 1
.. _ - .. ... . . ~ - - . _ _ . - -. ~ . - . . . _ . - . . . . _ . - . . . - . .
Responses and Funher Clarifications to NRC Questions from September 29,1998 Meeting l
l Question 21:
s Reference page F-6 of the Topical Report. Clarify the spool piece tolerance limits, e.g.
l lo,2a,95% confidence interval.
1 Answer:
I l l 1
l Attachments:
None.
Additional Clarification Requested:
Clarify the use of" tolerance limits"(tolerance interval?) It also appears the number of-
' spool pieces tested is discounted in the confidence interval development.
l Answer:
i l(3 See the answer to the additional clarification request for Question No.19 for discussion
' 'd of the statistical development [
l i
1 i
Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting l Question 22:
1O What fluid velocities can be achieved during laboratory testing? Explain how lV extrapolation for Reynolds Number is handled and how its uncertainty is bounded and i
confirmed in the plant.
Answer:
l Hydraulic modeling is performed at a test facility using the chordal LEFM spoolpiece and a geometric scale model of the actual hydraulic configuration at the plant. Reynolds Number is the ratio ofinertial force on a fluid particle to the viscous force on the particle.
l In feedwater systems, the dominant force is typically inertial, evidenced by a Reynolds number of between 10 and 30 million. To ensure that inertial and viscous forces are well represented in the model, the ideal scenario would be to run the hydraulic test at the same Reynolds number that occurs in the plant. Unfortunately this is not physically possible, due to the inability to conduct full flow testing at typical feedwater temperatures in the l range of 350-430 F. Consequently, it is necessary to extrapolate profile factor results l obtained at a flow measurement facility with Reynolds Numbers in the I to 6 million l range to the plant Reynolds Number in the 10 to 30 million range.
l l
Attachment 1 is an excerpt of a hydraulic test report from Alden Laboratory. It shows that weigh tank measurements are made for a series of flow rates from 8 feet per second to 38 feet per second (versus 15-20 fVsec typical ofin-plant feedwater flow rates). At ambient temperature and pressure, these flow rates correspond to Reynolds Numbers
_ from 1 to 6 million. These represent typical test results.
N
[ ]
Attachments:
- 1. [ ]
- 2. [ ]
- 3. [ l l 4. [ ]
l l
! Additional Clarification Requested:
l If there are flow components that cannot be seen by the LEFM 4 path arrangement add a discussion on those type of flow components.
I Answer:
i l The attached discussion addrenes this question in detail. In summary, the LEFM/ four path arrangement is robust with respect to asymmetric axial and transverse flow O
V 1 l
l
l Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting components because it samples the flow profile four times within the measurement p/
(,
. section, along each of the four paths. Upstream hydraulic features such as bends and tees cause axial and transverse velocity distortions which have been proven through testing to l
alter the profile factor (and thus, calibration) of the LEFM/ only slightly, I
1 See the attached discussion for more information on LEFM/ measurement in distorted 1 hydraulic conditions. The entire attachment is proprietary to Caldon Inc. l 1
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, - . ._ . , ~ . .. - . . - ~ . . - - - . . .- -- . . . . ... -
Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting -
! . Question 23:
,e
( How are swirl and cross flow handled with the LEFM/?
Answer:
Cross flow is defined as any variation of non-axial flow through the pipe. A special
, circumstance of cross flow has been called " swirl" Swirl is a clockwise or counter- '
j clockwise component of a flow profile that causes the profile to rotate as it proceeds down a pipe. It can be visualized as a corkscrew or screw thread path down the pipe.
The answer to this question will employ the swirl case as an example of cross flow and how it is handled.
1 I
l l
1 Attachments: 1
- 1. [ ]
Additional Clarification Requested l/( None.
'f .
i ,
Respons:s and Further Clarificztions to NRC Questions from September 29,1998 Meeting i Question 24:
l r'
)
( Provide additional information to support the claim in the Topical Report analysis that !
many LER overpower events would have been prevented with the LEFM/. '
Answer:
I I Note: Answer is entirely proprietary to Caldon Inc. i l
l 1
Attachments: ,
1
- 1. Figure 5-2 from the Topical Report," Sustained Overpower Events Reported in j LER's,1981-1997." !
Additional Clarification Requested:
None.
1 l
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Responses and Funher Clarifications to NRC Questions from September 29,1998 Meeting I
Question 25:
f^x Are the LEFM/ failure modes different than a venturi? If so, explain. Could any i] LEFM/ failure modes cause an overpower event?
Answer: I l l The general categories of LEFM/ failure modes are the same as those for a venturi, although the specific failure modes differ. As the discussion below explains, no LEFM/ ,
failure modes have been identified which could lead to an overpower event. [ l l
1 l
i Historical Performance and Design Imorovement The LEFM/ design evolved from years of experience with both Caldon and l' Westinghouse LEFMs as documented in the answer to Question 4 and Section 7 of the Topical Report. It is this operating experience which provides reasonable assurance that the failure modes of the LEFM/ are understood. The LEFM/ design process, installation process, hardware design, software design and on-line diagnostics were developed to minimize the probability of known failure modes and ensure that they will be annunciated if they occur. In summary, no credible LEFM/ failure modes have been i identified which could lead to overpower events.
rx b Attachments:
None.
Additional Clarification Requested:
None.
I
r i Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting Question 26:
b
. .' V What is the LEFM/ averaging period and how is it selected?
l l Answer:
i 1 I i
Note: The answer is entriely proprietary to Caldon, Inc.
Attachments:
None.
Additional Clarification Requested:
None.
l 1
O I
1
. - - . _ . . - . . . - . - -,. .- - _, . = , _ . . -
.- _. . _ . _ . _ . . . . _...m._. . _ _ . _ _ _ _ . _ _ _ _ _ _ _ . _ . _ . . . . . _ . . . _ . . _ . . .
i.
I Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting l
l ' Question 27:
Clarify where [ ] uncertainty referenced on page 5-6 of the Topical Report is included in the overall uncertainty. Explain the sources of[ ] uncertainty and
- appropriate averaging period. Explain how [. ] is determined [ ] as noted in the Topical Report.
Answer:
1 1 l
Note: The answer is entirely proprietary to Caldon Inc. l Attachments:
None.
Additional Clarification Requested:
None.
CJ' l
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-~ -- . .. . - _ .- - . . .- - - . - . - . - . . . -
1 Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting l
Question 28:
lfh l Provide more data on the historical performance of the LEFM. (CPSES use and expenence)
Answer:
I I Note: This answer is entirely proprietary to Caldon, Inc.
Attachments: None.
Additional Clarification Requested:
Provide clarification of"EPRI Standards". (We have also elected to provide additional l information regarding LEFM performance at Comanche Peak and elsewhere). j Answer:
EPRI Guidelines The EPRI guidance is contained in EPRI TR-103291s, " Handbook for Verification and Validation of Digital Systems", also included in the response to question No. 25 on i September 29,1998. )
LEFM Ooeratinn Exoerience
"( LEFM's have been operating continuously for over 24 years in nuclear power plants.
I 1 As funher support of LEFM performance in the field, actual data from Comanche Peak Units 1 and 2 are plotted in Figures I and 2. These figures show venturi bias as indicated by two independent instruments; LEFM and first stage pressure (corrected for blowdown flow). The figures illustrate three points:
. . The LEFM is in very good agreement with the next best independent indicator of feedwater mass flow in the plant, first stage pressure, and
. both of these indicators consistently reflect dynamic venturi bias over the course of operating cycles at Comanche Peak; likely due to venturi fouling.
. Relative indication: such as the first stage pressure in these plots do not provide the repeatability or assurance required for power determination.
Since there are no highly accurate absolute standards in feedwater flow measurement applications, an application of the LEFM on the Alaskan Pipeline was used to determine l repeatability of the instrument in service. There are a total of 23 chordal LEFMs installed L. along the 800 mile length of the pipeline. These LEFMs form the backbone of a sophisticated leak detection system. Of these LEFMs there are 9 pairs which are installed close enough to each other and without branch lines between to allow direct cross V
!Q i
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Responses and Further Clarificttions to NRC Questions from September 29,1998 Meeting t
comparisons. These cross comparisons can be used to estimate the in service !'
/~T repeatability of these chordal LEFMs. Figure 3 depicts the repeatability calculated 'ia
- 'V
~
cross comparisons of the LEFMs, and demonstrates an estimated repeatability of 0.1% or ,
better.
i
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2
. O O O Figure 1. Comanche Peak Unit 1: Fouling Indications 1.5% i - -
e a at 1.3%
t
[%-# ':, mE l'
I m" a E 1.1 %
i, , ) -
g-m --- 8
,e
,p q M ' ----
- 0.9% ** g [,O +
- g. . * +
g !
0.7% * ,
a2 0.5% a n
}. Outages Trip
_ Trip .
$ 03% , Trip + LEFM Fouhng indcation E
a 1st Stage Turbine Press. Indicated Fouhng i 0.1% -
(Corrected for Blowdown Flow)
_o 3g/2B/95 01/26/96 04/25/96 07/24/9610/22/96 01/20/97 04Q0/97 07/19/9710/17/97 01/15/98 04/15/96 07/14/9610/12/96 01/10/99
-03%
-0. 5% ---- -- -
Date i
t
O O O Figure 2. Comanche Peak Unit 2: Fouling indications
.1st Stage Turbine Press. Indcated Fouling (Corrected for Blowdown Flow) 1.3% . LEFM Fouhng Indicaten - .- .. p .
1.1 % ---
0.9% "
k O .7% -
- - -- E --
f- ^{f ,. =<f , Q 5 03%
n .
a - -+
- w f l' w,
0 i% .K. ~
.;.A v.
_o 93(0 5/96 05/15/96 06/23/96 12/01/E @/ N 06/19/97. 09/27/97 01/05/96 04/15/96 07/24/96 11/01/96 02/09/99
-O3%
y Outage
-0.5%
Date
i i
a i
Figure 3. Repeatability of LEFMs in Alaskan Pipeline Calculated Based on Cross Comparison of Suction and Discharge LEFMs at each Pump Station 0 25% - -- - - - - - - -
4 0.20 % - - - - - - - - - - - - - - - - - - -
i -
8 l, 2 -
i a
g 0.15% -- -
' o E-
=
b
- 25 0.10% - - - - - - - - - - - - - - - - -
5 a: ,
0.05 % ~
0 00 % , , r- r , . , 1 .
2 3 4 6 8 9 10 11 12 Pump Station Note: Only includes data from Pump Stations without active branch lines between Suction and Discharge LEFMs.
Data are 2 minute averages.
P
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/ i Attachment to Clarification for Question 28 ,
Note: This attachment entirely proprietary to Caldon, Inc.
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_ __ _=m__ _ _ _ . ___ _ _ _ . _ _ _ . _ _ _ _ . - _ _ . _. _ _ _ _ _ _ . _ ._
\
Responses and Funher Clarifications to NRC Questions from September 29.1998 Meeting question 29:
l V,m How is the LEFM used currently to provide correction factors to the venturis? Is the correction determined on the basis of the absolute accuracy or the repeatability of the LEFM7 .
Answer:
The LEFM is used at Comanche Peak to directly calibrate the nuclear instrumentation.
The correction factor is used only to keep the venturi calibration contemporary for use in 1 the event that the LEFM is unavailable. I A correction factor is calculated in accordance with a plant procedure which has its methodology based on approved calculation. A minimmn of 50 separate two hour data sets of FW mass flow rate from the LEFM and venturis are recorded in a spreadsheet.
The percent difference of each data set, the average percent difference of all data sets, and the standard deviation of all data sets is calculated. The correction factor is calculated from the average percent difference plus the two standard deviation margin.
The spreadsheet calculation is independently reviewed, documented by a TE, and given to the System Engineering Computer Group to implement in the appropriate plant computer software under an approved change process.
The Plant Computer multiplies the feedwater flow rate as determined by the venturis by the correction factor. This correction is displayed on the plant computer as " NET LEFM l CORRECTED POWER" and is available for use when the LEFM is out of service. The s) LEFM is used directly when it is in service. The 2 standard deviation margin used in the i
correction factor calculation prevents this corrected MWth from being equal to the MWth !
calorimetric power determined directly from the LEFM.
The correction is based on the absolute accuracy of the LEFM but a high degree of repeatability is also required.
Attachments:
None.
Additional Clarification Requested:
None.
f' l
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I O I l
l Responses and Funher Clarifications to NRC Questions from September 29,1998 Meeting
, Question 30:
What action is taken when the LEFM fails?
4 Answer:
It is only necessary that the LEFM input to the plant calorimetric be operable during the performance of the daily surveillance that normalizes the Nuclear Instrumentation System and N-16 power indications to the secondary calorimetric measurement. Current administrative controls (plant procedures) specify equipment operability requirements necessary for the calorimetric measurements and several levels of approved alternate
! methods to be used if the preferred instruments are not available. Currently, with the use of any of the approved instrumentation, the uncertainty associated with the power calorimetric measurement is within the allowance provided in the safety analyses. When the use of the reduced uncertainty associated with the LEFM/ is approved in support of an increase in the Rated Thermal Power, these procedures will be enhanced to require that the plant be operated at a power level consistent with the instrumentation used to perform the secondary plant calorimetric. If the LEFM/ is not available during the performance of the required calorimetric measurement, the plant power level would be reduced to operate at a power level consistent with the uncertainty associated with the instruments used for the calorimetric power measurement.
The Plant Computer monitors the " quality" of the LEFM data. Failure of the LEFM system will cause the Plant Computer to label the output of the calorimetric as bad and display and alarm this failure to the control room. Also, when the quality checking of the LEFM causes an Alert condition which indicates that some parameter is degrading, the Plant Computer marks the output of the calorimetric as Suspect to inform Operations that a problem could be occurring in the LEFM system. After Plant Computer notification, Operations follows the procedure to go to Corrected LEFM, Venturi, or Manual calorimetrics.
Attachments:
None.
Additional Clarification Requested:
None.
O v
l
l Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting i
Question 31:
i v Explain how Figure 5-2 in the Topical faport was made. Specifically address how the curves were fitted to the information presented in Table 5-1.
I Answer:
l l Figure 5-2 of the Topical Report (attached) shows the probability density curve for plant operation in the vicinity of 102% of the licensed thermal power using the existing venturi based instrumentation and using the LEFM/. This answer is intended to clarify three aspects of this figure. These are (1) the development of the curves upon which the figure is based, (2) the relationship of the Figure to Table 5 1, and (3) reconciliation of the vertical scale that appears on the figure with the probability of exceeding a certain power level. These aspects are addressed below.
1
- 1. Development of the Curves in Figure 5-2. Figure 5-2 was created assuming normal distribution curves for the uncertainty of each instrument set and based on a thermal power uncertainty (2a) for the venturi of 1.4% and, for the LEFM/, ofi0.6%. The venturi-based curve is centered on 100% thermal power and the LEFM/ curve is centered at 101% power to reflect a 1% uprate. The full scale normal distribution curves corresponding to Figure 5-2 are shown in Figure 1, attached to this answer. Figure 5-2 l I
and the attached Figure 2 provide a close-up of the region of the normal distnbution curves in the vicinity of 102% power to highlight the differences between the venturi and LEFM/ curves in this region. Note that Figures 1 and 2 depict probability density.
O h Normal distribution curves were created using the following equation for the normal probability density function :
3
_.l [x uh2 I l f( x)= e k"/
a- j where is the mean of the distribution and o is the standard deviation. The following data were used in creating Figures 1 and 2, and Figure 5 2 in the Topical Report.
Data Used in Topical Report Uncertainty Mean (2a) (p)
Venturi 1.4% 100% power LEFM/ 0.6% 101% power i Bowker and Lieberman, Engineerine Statistics. Prentice Hall, Inc.: 1972.
O U
Responses and Funhar Clarific"tions
. to NRC Questions from September 29,1998 Meeting l
- 2. Relationship of Figure 5-2 to Table 5-1.
O
() Table 5-1 from the Topical Report is repeated below for clarity of discussion.
Table 5-1. Probabilities and Odds Associated With Nozzle and LEFM/ Uncertainty Bounds Number of Venturi Nozzle LEFM/ Probability of Operation Odds of Exceeding Standard Bounds (t) Bounds Within Bounds Bounds on the High Deviations (t) Side 1 0.7% 0.3% 68% 1/6.3 2 1.4% 0.6% 95.4 % 1/44 3 2. I% 0.9% 99.7 % in41 4 2.8% 1.2% 96994 % 1/32,300 5 3.5% 1.5% 99 9 994 % 1/3.3 million In short, Figure 5-2 plots the probability density function in the vicinity of 102% power for the venturi and the LEFM/ using the equation described in Part 1 of this answer.
Looking at the entire probability density function curves in Figures I and 2 attached, the
" probability of operation within bounds" from Table 5-1 above is the area under each curve (the integral of the density function) within the bounds expressed in Table 5-1. The
" odds of exceeding the bounds on the high side" from Table 5 1 is the probability of l operating in the region to the right of the selected bound, expressed as a ratio. For example,102% thermal power can be described as the +1.0% bound on the LEFM/
curve centered at 10l% power. The probability of exceeding 102% thermal power is ;
illustrated by the area under the normal distribution curve to the right of 102%, or:
l
..!.. p[ 2 P= e \" dx a- 2x
'102 Figure 3 depicts the result of this integrati3n for the venturi and LEFM/ case in the Topical report in the vicinity of 102% power. Solving the integral above for each instrument set yields the following probability of exceeding 102% of thermal power:
Probability of Exceeding 102% Thermal Power
% Odds Venturi 0.2% 1/500 LEFM/ 0.04 % 1/2000 O
O
. _ _ . . _ _ _ _ ,_ . __ _ . . _ _.- _.. . m.. . .__ , _ . _. . _ .
Responses and Further Clarifications to NRC Questions from September 29,1993 Me: ting i
- 3. Verticci Scale on Figure 5-2. The vertical scale on the attached Figure 2 and on f Figure 5 2 in the Topical Report (i.e. the numerals that appear along the y-axis) is the
- scale that appears on normal distribution curves for probability density. The numbers appearing on the y-axis are associated with normalization of the curve such that the area beneath it is equal to one. In short, these numbers have no direct relevance to the probability argument, which is an argument based on areas under the curves rather than specific y values.
i f
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v.-< ~ w H - +e- ~cm -,
e- -
0.025 0.020 \\
.s I .LEFMFdwith 1% uprate "g Current instrumentation
\
g g 0.015 i
@ \
E \
f 0.010 \
g I \
li \
$ 0.005
\
0.000 I I I I II I I I I I I I I N ' 'l I I 100.5 101.0 101.5 102.0 102.5 103.0 Power (percent of currentlicense)
Figure 5-2. Probability of Exceeding Power Levels in Vicinity of 102% Licensed Power 5-8
O O O .
Figure 1. Probability Density Function lilustrated in Top 6 cal Report 1.40 --- -- -- - ---
- n.
t 1.20 - - - - - - - - - - - - - - - - - - --- -- - - - - -
l --i----- - '
1.00 - - - - --
+
0 80 --- - - - - - - - - - - - --
,a -
--- 5-Venturi (2 sigma =1.4%) ,
- - - - - - LEFM with 1% uprate (2 sigma =0.6%), ,' ; i 0.60 - - - - - - - - -
I- - - - - - - - -
0.40 -- - - - -
- t. :
0.20 ,
i - ,
1 97 98 99 100 101 102 103 Power (percent of current licensed power level) l
F bv s/
i Figure 2. Probability Density Function lilustrated in Topical Report in the Vicinity of 102% Licensed Power 0 025 -- --
- - - - - - - --. - - - - - - - -~
-- - - q )
i 0.020 - - - - - - - -- -- 2 I - -- -
! f k'
l 0.015 - .- - - - - - -- --
t
_ _ _ _ _ _ _ _ _1.__ _ I.
Venturi (2 sigma =1.4%) ,j
- - - - - - LEFM with 1% uprate (2 sigma =0.6%)
'. l i
0.010 -- -- - - - - -
i.
t
- i 0.005
\,.
100.5 101 101.5 102 102.5 103 Power (percent of current licensed power level)
O O O >
Figure 3. Probability of Exceeding Power Considering Thermal Power Uncertainty in Topical Report .
0.02 - - - - - - - - - - - -
0.018 --- ---- --
i ,
I
! 0.016 -
-- - - - - - " - ----2 - -- - - - - --
0.014 - - - -
5 --- - - -- --
0.012 ,
Venturi (2 sigma =1.4%)
. - - - - - - LEFM with 1% uprate (2 sema=0.6%)
0.01 - - - - - - - - - -
-; --- - = = = ~ = = = = ~'- -- -
0.008 - - - - - - - - - '- .
0.006 - -
0.004 -
0.002 .,
0 l
a 1
1 --
~. .
'~~-+
4-101 101.2 101.4 101.6 101.8 102 102.2 102.4 102.6 102.8 103 Power (percent of current licensed power level)
.._ ._ . _ . . . . . . .m . . . . . . . . _ . . _ . . . . - -
h Responses and Further Clarifications to NRC Questions from Srptember 29,1998 Meeting i Question 32: -
O V Regarding the answer to Question 10 in the handout material from the most recent i meeting, were the uncertainty values for both the venturi and LEFM arrived at using the . '
same methodology? What methodology was used? Please give a detailed description of any differences in the combination of uncertainties as presented in the topical report.
Answer:
The uncertainty values for the LEFM/ and for the venturi were arrived at using the same methodology as described in the topical repor'.. In methodology, there is no difference between the combination of uncertainties for these site specific cases as compared to the methods presented in Chapters 3 and 4 and Appendices A and E in the topical report.
Attachments:
None.
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Responses and Funh*.r Clarific_tions to NRC Questions from September 29,1998 Meeting Question 33:
Explain in specific terms why the venturi uncertainty at Comanche Peak is so much lower than that discussed in the Topical Report; i.e. what uncertainty factors are different and why?
Answer:
Fundamentally, the Comanche Peak venturi-based thermal power acertainty is lower than that presented in the Topical report because the Comanche Peak venturi based thermal power calculation uses precision differential pressure cells calibrated for optimum accuracy at full power. This contributor for the Comanche Peak case is almost l
half the uncertainty (twice the accuracy) of the bounding assumptions in the Topical Report. The attached table compares the Topical Report case to the Comanche Peak case in detail.
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V V V Attachment to Question 33 Response.
Companson of Topical Report Results to Comanche Peak S4e-Spechc Thermal Power Uncertainty Based on Preosson VenturiInstruments Topical Element Topical Element Topical Report Comancho Peek Topical Venturi Topical Venturt Comanche Peak leem Allowance 2 eigma Allowance 2 sigma 2 Loops (%) 4 Loops (%) Uncertainty (%)
1 Feed Flow Nozzle Coefficient O 5% of flow 0.5% of flow 0.35 0.25 0.5 2 Feed Flow Nozzle Dunensions ind. In Coefficsont incl. In Coefficient incl. In Coefhcient incl. In Coefhcient incl. In Coeffoent 3 Thermal Expanson - Properbes 10 % 5% 0 07 0.07 0 06 4 Thermal Expanson -Temperature 2.5 degrees F 5.0 degrees F 0 0 0 01 5 Differenbal Pressure - Systematic 2% of full range 1.157% of full range
- 1.06 1.06 0707 Differential Pressure - Random not apphcable not appbcable 0.75 0.53 n/a 6 Feed Density- Correlation 0 05 lbs/os ft not apphcable 0 05 0.05 0 7 Feed Density- Temperature 2.5 deg FKL12 ts/cu ft 5 dog F/ 044% per F 0.08 0 06 0 22 8 Feed Densaty- Pressure 20 psWD 005 bs/cu ft 11 psWO.00038% per psi 0 0 0 004 9 Feed Enthalpy- Temperature 2.5 deg F/2.7 blunb 5 dog F/.1430% per F 0.25 0.18 0.715 10 Feed Enthalpy- Pressure 20psif.02 btuab 11psil.0001035% per psi 0 0 0 001 11 Steam Enthalpy- Monsture 0.25%f1.65 btunb 0.25%and .85%/%mst. 0.21 0.21 0 21 12 Steam Enthalpy- Pressure 20 psi /0.75 btuab 11 psWO.00491% per psi 0.1 0.1 0 054 13 Other Gains and l_osses 10% of each item Smlar basis 0 07 0.07 0 085 14 Blowdown assumed in item 13 10% 0 0 0 01 Net error due to temperature (item 7+1 tem IMtem 4) 0.33 0 24 0.925 Net error due to pressure (Item 8-Item 10) 0 0 0 003 Total Uncertainty, Thermal Power 1.40 1.26 1.29
- restncted to full power operaton Note. Comanche Peak Data From TU Electne Calculation RXE-TA-CP2SO23, Rev. O. ,
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I Responses and Further Clarific:tions to NRC Questions from September 29,1998 Meeting Question 34:
(O g Provide a figure analoFous to Figure 5-2 in the Topical using the Comanche Peak site-specific uncertainty values for the venturi and LEFM instruments.
Answer:
Figure 1 presents the probability density for the Comanche Peak site-specific uncertainty values of 1.29% for the venturi and 0.56% for the LEFM, using the same method as employed in the Topical Report. Figure 2 is the probability of exceeding any particular power level (the integral of the density curve) for the same case. Comparing this result to Figure 3 shows that operation with the Li:FM is less likely to result in operation above 102% power than with the venturi instruments in both cases. The numerical results are as follows:
Probability of Exceeding 102% Thermal Power at Comanche Peak Using Site-Specific Uncertainty Values
% Ratio Venturi (l.29%) 0.1% 1/1000 LEFM (0.56%) 0.03 % 1/3000
^
Under the current regulations, licensees may maintain a she-specific thermal power uncertainty as large as i2%. Therefore, Figure 4 is presented for consideration. Figure 4 compares the proposed accuracy requirement with the LEFM/ uprate ofi0.6%
uncertainty centered about 10l% power to the current limit ofi2.0% uncertainty centered about 100% power. Figure 3 illustrates that the safety benefit associated with the LEFM/ uprate, which would regulate licensees to maintain i0.6% accuracy, is significant as compared to the current regulations. Comparing the 2% current regulation to the 0.6% LEFM/ proposal (including the uprate) gives the following results:
Probability of Exceeding 102% Thermal Power
% Ratio Venturi (2%) 2% 1/40 LEFM/ (0.6%) 0.04 % 1/2000 I
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- m. ._ __._ _._ _ . - . - _. _ . ~ . . ... . .. _ _ . _ . _ . . _ .
Figure 1. Probability Density Function Considering Comanche Peak Data in the Vicinity of 102% Licensed Power 0.025 --~ - - - - - - - -- -
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- I 0.020 -- --- --- 5- - - --- - -
i 0.015 -- - -- ---- - - - - - - -
- --- { - - ---
Venturi (2 sigma =1.29%) !
- - - - - - LEFM with 1% uprate (2 sigma =0.56%) J ",
0.010 - - - - - --
--i: I i
t e l 0.005 --- - - - - - -
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-}.
100.5 101 101.5 102 102.5 103 Power (percent of current licensed power level)
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O O O Figure 2. Probability of Exceeding Power Considering Comanche Peak Data ,
4 0.02 -- -
I t 0.018 - -- ---
--5 '
, i 0.016 - - - -- -- -- - - -- - - - - - - - - - - - - -
k '. ;
0.014 - - - -- - - - - - -- - - - - - - - - - - - -- - - - - -
'. t 0.012 -- - ----- -
Venturi (2 sigma =1.29%)
- - - - - - LEFM with 1% uprate (2 sigma =0.56%) I 0.01 -- - - - - - - ----
t t
0.008 - --- - 5--- -- ---- - - - - - - - - - - - - - I s
0.006 -
k - -- - - - - - ---- - --
i 0.004 - --- -- --
--( - - - - - - - - - - - - - - - - - - - -- --
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0.002 . !
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-+-
'.., --- ~
. t O - -- - -
1 101 101.2 101.4 101.6 101.8 102 102 2 102.4 102.6 102.8 103
- Power (percent of current licensed power level)
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Figure 3. Probability of Exceeding Power Considering Thermal Power Uncertainty in Topical Report 2
0.02 -- - - - - - - - - - - - -
O.018 - - - - -- - - - -
-1 --- - - - - - - - - - --
0.016 --- --
--- - - - - --- -- - - - - - - ~- ~---
- i 0.014 - - - - - - - - - -
1 0.012 -- - - - - -- - - - - -
-- - ---_*-- ~ - - - - - - - ---
. Venturi (2 sigma =1.4%)
- - - - - - - LEFM with 1% uprate (2 sigma =0.6%) ,
0.01 = = = - ~ = = = = = "--- ---
--t i
- t 0.008 - - -
0.006 - - -- --- - - - -- -- - - - - - -- - - - - -- -- -
0.004 - - - - - -
~
, l 0.002 -- - - - - - - --
0 6- + - N --
- 101 101.2 101.4 101.6 101.8 102 102.2 102.4 102.6 102.8 103
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Power (percent of cunent licensed power level) b
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i Figure 4. Probability of Exceeding Power Considering Venturi Uncertainty of 2% -!
0.2 - - -
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O.18 -
i 0.16 -
- l, - - - - - - - - - - - - ' - - - - - - - - - - - --- - - - - - -
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0.14 - - - - - - - - - - - - - - - - - - -- -
s 0.12 -
, Venturi (2 sigma =2%) ,
--- - -LEFM with 1% uprate (2 sigma =0.6%)
0.1 - -- , - - - - - - - -- - -
0.08 - - - - - I - - - - - - -- --- -- -
t 0.06 - - - - - - - ---
r 0.04 - --
0.02 -- -
W O ' ' + -
i 101 101.2 101.4 101.6 101.8 102 102.2 102.4 102.6 102.8 103 Power (percent of current licensed power level) i l
l Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting l
Question 35:
The Caldon Topical Report and the Answer to Question 25 explain that a benefit of the LEFM is that it is a self-contained " integrated" system. Beyond on-line diagnostics I capability, please discuss in the application of the LEFM at Comanche Peak how common mode failures are avoided such that the uncertainty values assumed for the LEFM remain valid during plant operation. Was any type of Failure Modes and Effects Analysis conducted during system design?
Answer:
As part of a critical design review performed by an independent contractor in 1994, fault tree and failure modes and effects analyses (FMEA) were performed for the LEFM 8300 system. The fault tree analysis identified major LEFM components or functional blocks within components whose failure could lead to " top undesired events". These are defined ,
as events which could cause a flow measurement error without alerting the user. l l
The results of the fault tree analysis focused the FMEA, which defined the effects of the identified failures on the system and the method of detection for each of the identified failures. Common mode errors were considered as part of this work, and potential failure modes were assessed for probability of occurrence. Design improvements were incorporated into the LEFM 8300 and LEFM/ designs as a result of this work, and these analyses are currently undergoing revision for the LEFM/ system.
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l l Responses and Funher Clarifications to NRC Questions from September 29,1998 Meeting Additional Clarifications In Response to Questions Raised by the Staff at the
'(U) September 29,1998 Meeting In addition to the 35 responses and clarifications provided by item number, two other issues were raised during the meeting and were discussed during follow-up telephone conversations with the Staff. These issues are summarized and addressed below.
- 1. LER's The Staff requested that Caldon provide the list of LER's used for the figure in the Topical Report to the NRC. The Staff requested that Caldon provide the list by LER Number, and by categories used in the Topical Report. The list is provided as Attachment I to this document.
- 2. Acceptance Criteria There was considerable discussion during the meeting regarding specifications, qualifications, factors, or features which would make an instrument acceptable for use in conjunction with a 1% power increase. In response, Caldon has summarized the factors considered by Caldon to demonstrate instrument performance sufficient to warrant operation at the increased power level. Caldon has discussed these criteria with the Staff and presents them for further consideration. In summary, the LEFM/ meets the following criteria:
O V
- 1. Instrument uncertainty must be equal to or less than i 0.6% thermal power (2 standard deviations, normally distributed) or better. This leads to a probability of exceeding the analyzed power ofless than 1 in 2000,
- 2. Instrument uncertainty contributors must be combined by the root sum squarea if independent and algebraically if correlated and systematic.
- 3. One must be able to define what the instrument measures and how the measurer tent is related through physical principles to thermal power.
- 4. The instrument must have an established record of performance consistent with its analyzed accuracy.
- 5. Model test data, traceable to national standards, must be sufficient to assure that all instrument sensitivities are identified and bounded. Uncertainties arising due to all potential differences between test and plant conditions must be explicitly identified and bounded.
- 6. Modeling and extrapolation uncertainty bounds must be validated using data from the mstalled instrument in the plant.
! 7. Periodic or continuous verification is required. Continuous verification of significant contributors to the thermal power uncertainty (feedwater flow and feedwater ia
Responses and Funher Clarifications to NRC Questions from September 29,1998 Meeting .!
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temperature) is required. Other contributors must be periodically verified. For
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instnaments subject to periodic verification, instrument uncertainty must allow for any potential indication changes during the interval between verifications. ;
J See Attachment 2 for more detail on these criteria. !
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Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting
[ Attachment I
(,/ List of LER's Events Due to Feed Flow or Temperature-Related Calculation Errors LER No. Docket No.81-016 50-298 86-025 50-483 90-012 50-219 95-004 50-220 95-006 50-443 94-019 50-298 Events Due to Feed Flow or Temperature-Related Instrument Errors LER No. Docket No.82-002,82-034 50-333 82-024 50-260 83-024 50-029 83-027 50-309 85-008 50-346 !86-004 50-237 86-025 50-483 87-011 50-482 87-034 50-237 88-028 50-361 &
50-362 88-035 50-361 90-003 50-033 91-008 50-219 92-018 50-305 91-030 50-245 92-014 50-277 93-008 50-324 i
94-001 50-301 94-002 50-311 94-012 50-271 95-003 50-388 95-008 50-296 94-003-01 50-354
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i Res'ponses and Further Clarificulons to NRC Questions from September 29,1998 Meeting -
I[ Incidents Due to Other Core Thermal Power Error or Failure of Other Instruments i
V.
r LER No. Docket No.83-027 50-321 90-012 50-461 t 93-001 50-220 95-010 ' 9-458 - I 95 011 :s-410 95-013 95-043 50-416 50-336
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95-008- 50-388 95-039 50-354 95-021 50-237 95-015 50-387 &
$0-388 e 95-012 50-293 l 96-002 50-352 96-001 50-277 96-006 50-255 !
94-001-01 50-301 ;
94-003-01 50-354 i
% -013-00 50-341 3
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Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting i
l Attachment 2 l
/' Criteria
(
Bases for Acceptability of 1.01 Operating Margin Using Enhanced Feedwater Flow Measurement Technology l
' The following paragraphs provide the detailed criteria and bases for the acceptability of a p +er uprate in accordance with the use of the LEFM/ for thermal power measurement. Each of these criteria is essential to the demonstration of acceptability.
- 1. Acceptability of Operation at 1.01 Times the Licensed Thermal Power Based on Instrument Accuracy An allowance of 0.01 of the licensed thermal power of a nuclear power plant provides sufficient margin for the uncertainties in the measurement of thermal power as these uncertainties affect the analyses of the transients and accidents in the licensing basis for the plant, provided the total uncertainty in the measurement is normally distributed about the licensed thermalpower, with two standard deviations equal to or less than 0.006 ofthe i licensedthermalpower. That is, analyses ofloss of coolant accidents and other transients and accidents in the
! safety analysis report originating from a " full power" condition may be performed at a power level of 1.01 times the licensed thermal power. More specifically, this criterion applies to the sections of Chapter 15 of the Standard
{
Review Plan listed in Attachment 1. This criterion is subject to the conditions enumerated in 2 through 6 below. !
Basis:
This criterion isfounded on the specifiedstandard deviation ofthe normal uncertainty distribution, which leads to a probability, due to measurement uncertainty, ofpower level exceeding 1.01 times the licensedpower ofless than 1 in 1000. It isfurther based on priorfindings ofthe NRC staffrelative to the consequences ofoverpower. In connection with the [1992] revision to 10CFR30.46, the staf]' held that a l
., power level as much as [3%) above licensedpower had little efect on thepeak clad temperature in a i
'{
,s loss ofcoolant accident analyred using Appendix K.
2, Methodology for Uncertainty Accounting All uncertainties in the thermal power determination must be accounted and combined in accordance with procedures and methods specified in ASME PTC 19.1. That is, modeling and process variable measurement uncertainties shall be combined as the root sum squared if they are uncorrelated with one another and algebraically if they are systematically related.' It must be demonstrated that the aggregate uncertainty in the power determination does na exceed 0.006 of full power on a 2 standard deviations basis.
Basis:
The basesfor the treatment ofindividual uncertainties and biases and their combination is given in the referenced ASME standard This standard was developedfor the analysis ofuncertainties in acceptance testing ofsteam turbines, which testing requires a precise determination ofthermalpower. It is hence directly applicable to the determination ofthermalpower in a nuclearpower plant.
- 3. Completeness of Analytical Model The means for the determination of thermal power must be based on established physical principles, so that 2
sources of uncertainty can be identified analytically, as part of their design basis. Specifically, algorithms relating measured variables to the mass flow rate and energy content of fluids exiting from and returning to the i
l
' An example of the latter category: an error in the measurement of feedwater temperature by a resistance l thermal detector will lead to an error in the density input to a mass flow determination and an error in the enthalpy of the feedwater. The errors add algebraically in the determination of thermal power.
4 ;\ 2 That is, random uncertainties and undetected biases in measurements or algorithms l
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Responses and Funh:r Clarific1tions to NRC Questions from September 29,1998 Meeting l
l nuclear heat source must rest on recognized physical principles'.
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Basis:
A scientific analysis ofuncertainties, particularly those due to the modeline ofthe thermalpower measurement process is not possible without a complete set ofmathematical relationships between measured variables and the thermalpower. Such relationships also help to ensure that there are no errors ofomission in the modelingprocess; i.e., that the modelis complete. The completeness ofthe design basis is discussedin the SRP, Appendh 7.1-C. Section 4.
- 4. Established Performance Record 1
The means for determination of thermal power must have an established record of performance (i.e.,
measurement accuracy) comparable to that implicit in I above, in configurations similar" to that of the nuclear plant system in which they are applied.
Basis:
This criterion requires empirical confirmation ofthe completeness and correctness ofthe uncertainty analysis.
- 5. Bounding of Modeling Uncertainties by Test Constants in the modeling of the mass and'or heat transpon processes on which the measurement of the thermal power rests must be bounded by a test or tests', the results of which are traceable to appropriate standards.
Likewise, the uncenainties in these constants must be bounded by a test or tests. If the modeling test differs from the plant installation with respect to one or more modeling parameters, the uncettainties in the extrapolation from fg the conditions of the model test to the conditions of the plant must be explicitly considered in the determination of
' For example, measurement of mass flow with a nozzle rests on the relationship between the net force on the fluid entering the nozzle throat and the time rate of change of total fluid momentum--Newton's second law. This measutement complies with the requirement of criterion 3 because: (1) a set of equations relating the measured variables-nozzle differential pressure, fluid temperature and pressure, and the nozzle dimensions--to the mass rate of flow through the nozzle can be derived from first principles and (2) the sources of uncertainty in the mass flow measurement can methodically and inclusively be identified on a hypothetical basis. The magnitude of the uncertainty for each source can then be bounded rigorously by test and/or analysis. The explicit analytical relationships also facilitate the modeling, using accepted modeling principles, of the fluid system in which the measurement device will be applied, for the purpose of calibration. Rigorous modeling permits the quantification of effects (and errors) due to variables that cannot be duplicated in the calibration tests (e.g., the viscosity of water at high temperature and pressure).
Similarly, flow measurement using the transit times of acoustic pulses along chordal paths in a pipe rests on (1) the fundamental relationship between mean velocity, time, and distance traveled, and (2) the numerical integration of chordal mean velocities over the conduit area. This measurement therefore also complies with the requirement of criterion 3 because, again, the sources of uncertainty can be methodically and inclusively identified and bounded and definitive models for calibration can be constructed.
On the other hand, not all methods of ultrasonic flow measurement can be described based on first principles. For example, a flow measurement based on the Doppler shift caused by turbulent eddies would n9.1 comply because the fluid velocities thus determined cannot rigorously be related to the volumetric or mass flow and no straightforward modeling relationships can be established for calibration testing.
- The term "similar" is used here to connote similarity in the modeling sense, that is, mathentatically similar in terms of geometric scale, Reynolds number, fluid velocity , fluid properties and/or other parameters as appropriate to describe the physics of the measurement process.
' The discharge coefficient of a nozzle used to determine the mass flow rate of feedwater is an example of a (Vg) modeling constant.
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Responses and Further Clarifications to NRC Questions from September 29,1998 Meeting the overall uncertainty in the modeling constant (s). In addition, if the modeling constants rest on tests of devices
['T geometrically similar to the device (s) used for the determination of power, the uncertainties in the modeling
() constants must explicitly include allowances for the geometric uncertainties in both the tested device (s) and the device (s) to be used for the determination of power.'
Basis: \
This criterion requires a rigorous andinclusive bounding ofthepotential uncertainties due to the l modelin.g of the power determination process.
- 6. Validation of Modeling Uncertainties Those properties of the calibration model that affect the uncertainties in extrapolating model results to the plant' must be confirmed in the plant by test or other measurements, as appropriate. Any differences between model and plant must be analytically reconciled and accounted in the uncettainties in the modeling constants determined from the calibration test.
Basis:
The reconciliation ofin-plant conditions with model(i.e., cal re.aon) conditions ensures that any errors in the extrapolation process are accounted l
- 7. Verification of Design Basis Parameter Uncertainties:
Uncertainties in the measurements of the physical variables used in the algorithm for the determination of power' must be bounded by analysis of the components of each measurement. In addition, these bounds must be confirmed by tests of the measurement apparatus at the place of manufacture or in the plant, upon installation.
For significant contributors to uncertainty, such as feedwater flow and feedwater temperature, continuous verification is required. For those other instruments whose confirmation is periodic, the uncertainty in the fm affected variable must include an allowance for changes in components of the measurement apparatus that might 1
l take place during the calibration period. The allowance must be conservatively bas:d on actual experience with
() the measuremeni apparatus as well as tests to determine environmental effects that might not be encompassed by the experience base.
Basis:
This criterion ensures that varameter uncertainties are and remain within their design bases when the power determination process is used The rigorous continuing design basis assurance is warranted by the assumption in criterion I that the power determination uncertainty is now and will remain characteri:ed by a normal distribution with one standard deviation not exceeding 0.003 offullpower.
The intent ofthis criterion is to meet the versflability discussion ofthe SRP, Appendix 7.1-C, Section 4.
l ' For example, if an uncalibrated ASME nonle were used for the determination of mass flow, with a
! discharge coefficient based on tests of a nominally identical nonle, the uncertainties in the nonle used for l the mass flow determination must include allowances for the dimensional uncertainties in the throat
! diameter and upstream diameter of each nozzle as well as allowances for dimensional uncertainties in tap placement, tap configuration and nozzle surface finish.
For example, the transverse and axial fluid velocity fields upstream of a flow nozzle or ultrasonic transit time flow instrument.
' The differential pressure measurement and the throat and pipe diameters are examples of such variables
,-s for a mass flow determination from a flow nozzles; the transit time measurements, the non fluid time delay,
- ( ) the path length and the pipe diameter are examples for a volumetric flow measurement based on the transit U times of ultrasonic pulses.