ML20235U255
| ML20235U255 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 06/12/1987 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8707220411 | |
| Download: ML20235U255 (5) | |
Text
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Shippingport, PA 15077-0004-June 12, 1987 U..
S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington,.DC 20555
Reference:
Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 Request for Information on RTD Technical Specification Change Gentlemen:
By. letter. dated September 23, 1986, additional information was requested on.the overtemperature and overpower AT setpoints with respect. to Beaver Valley Unit 1
Technical Specification Change
- Requests, 116 and 116 Revision 1, dated January 14, 1986 and July 25, 1986, respectively.
In response to your request for information enclosed are:
1.
Three (3) copies of WCAP-11462 entitled, "Overtemperature.
and Overpower Delta-T Reactor Trip Setpoint Calculations for Beaver Valley Unit 1"
(Proprietary) and Supplement 1 of WCAP-11462.
2.
Three (3) copies of WCAP-11463 entitled, "Overtemperature and Overpower Delta-T Reactor Trip Setpoint Calculations for Beaver Valley Unit 1" (Non-Proprietary) and Supplement 1 of WCAP-ll463.
- 3., " Supplemental Information on RTD Replacement".
- Also, enclosed is a
Westinghouse authorization
- letter, CAW-87-034, Proprietary Information
- Notice, and accompanying F
e As item 1
contains information proprietary to Westinghouse n$$
Electric Corporation, it is supported by an affidavit signed by j
- RL Westinghouse, the owner of the information.
The affidavit sets forth the basis on which the information may be withheld from public i
-$g Eo disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.790 of the
.,g Commission regulations.
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Accordingly, it is respectfully requested that the information 5
which.
is proprietary to Westinghouse be withheld from public R$
disclosure in accordance with 10 CFR Section 2.790 of the m a.a-Commission's regulations.
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NL fM gSib OW u oo ecMA's~ coevader M
I Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 Request for Information on RTD Technical Specification Change Page 2 Correspondence with respect to the proprietary aspects of the Application for
?!ithholding or the supporting Westinghouse Affidavit should reference CAW-87-034 and should he addressed to R.
A.
Weisemann, Manager of Regulatory and Legislative
- Affairs, Westinghouse Electric Corporation, P.
O.
Box
- 355, Pittsburgh, Pennsylvania 15230-0355.
If you have any questions regarding this information, please contact my office.
Very truly yours,
.. (
- YlL,
. D.
Sieber h'Vice President, Nuclear i
cc:
(without WCAPs)
Mr. F.
I. Young, Resident Inspector U.
S. Nuclear Regulatory Commission Beaver Valley Power Station Shippingport, PA 15077 U.
S. Nuclear Regulatory Commission Regional Administrator Region 1 631 Park Avenue King of Prussia, PA 19406 Mr. Peter S. Tam U.
S. Nuclear Regulatory Commission Project Directorate No. 2 Division of PWR Licensing - A Washington, DC 20555
- Mail Stop 316 Addressee only L _. _ _
ATTACHMENT 1 BEAVER VALLEY UNIT 1 Supplemental Information on RTD Replacement Provided below is additional information on the replacement of the Sostman RTD's with Rosemount RTD's that may aid in your review of g
this matter.
1 Background
Rosemount 176KF RTD was identified and procured as the replacement RTD through our stock inventory request program when the Sostman RTD was no longer available in 1976.
The Rosemount RTD was recognized as acceptable because Westinghouse was supplying both Sostman and Rosemount RTD's for the narrow range RCS protection channel application during this time period.
1 When the stock of Sostman RTD's was depleted in 1981, our maintenance section started using the Rosemount RTD's that had been in stock since 1976 as replacements.
Four (4) Rosemount RTD's were used as replacements in March 1981.
Of these four (4)
RTD's, only one was used as an active protection channel input (Loop 2
cold leg).
In April, 1982 five (5) additional Rosemount RTD's were used as replacements, four (4) of which were active protection channel inputs.
At the time of the 1982 replacements, our Instrument and Control section asked Engineering to determine if the Rosemount RTD's were acceptable environmentally qualified replacements.
Engineering determined that they were environmentally qualified and recommended replacement of the Sostman with Rosemount RTD's.
Engineering also noted that there was a significant difference between the response times of the two types of RTD's and recommended that Westinghouse review the replacements both functionally and environmentally.
Although environmental qualification is j
documented, it appears that no functional review was
{
performed.
The remaining Sostman RTD utilized as an active protection channel input was replaced with a Rosemount RTD in November, 1984.
During the design of the modification to add filters to the protection channel T
and AT summators (DCP-695),
it
- appeared, from the infveormation we
- had, that there were no differences in the technical and procurement specifications of the Sostman and Rosemount RTD's.
This was confirmed by the Westinghouse site representative.
Based on this we concluded I
that there would be no change necessary to the Technical Specification Overtemperature AT and Overpower AT setpoints except for the addition of the lag compensation terms.
1
q ATTACHMENT 1 (Continued)
]
Page 2 l
The thermal EMF error associated with the Rosemount 176KF RTD's was not recognized as a concern until brought to our attention by the NRC reviewer for Technical Specification Change Request No.
116.
We performed a review of NRC Information Notice 0, Circulars and Bulletins and did not identify this concern as being previously identified to the industry by the NRC.
2.
Use of Existing Setpoints Westinghouse performed a setpoint calculation for Beaver Valley 1
to aid in providing a
response to the NRC request for information dated September 23, 1986.
The results of this calculation are provided in WCAP-11462 "Overtemperature and Overpower Delta-T Reactor Trip Setpoint Calculations for Beaver Valley Unit 1"
(Westinghouse Proprietary) and Supplement 1 of the WCAP.
WCAP-11462 is a
partial result of a
larger study being performed by Westinghouse for Beaver Valley 1 to update the basis for our protection systems setpoints to include a more thorough consideration of instrument inaccuracies and operating experience resulting in additional assurance of safe and reliable operation.
When this study is complete, it will be reviewed to determine if any changes to our existing Technical Specification protection systems setpoints are appropriate.
l Upon review of WCAP-11462, an evaluation of the calibration l
accuracies of the narrow range protection RTD's was initiated l
to assure they are consistent with the values specified in WCAP-11462.
As a
result of this evaluation, one active protection RTD was determined to be unreliable.
The installed spare at that location has been connected as the input to that protection channel.
All other protection channel RTD's were l
consistent with the WCAP-11462 accuracy requirements.
Verification of the narrow range RTD's calibration accuracies in conjunction with the setpoint analysis of WCAP-11462 i
provides assurance that BVPS Unit 1
can be safely operated using the existing Technical Specification overtemperature AT and Overpower AT setpoints.
Comparison of our Technical Specification change 1A-116 with WCAP-11462 indicates agreement of the Overtemperature AT and overpower AT setpoints with the exception of the wording of the allowable values in Note 3 of Table 2.2-1.
However, the 4%
of computed AT is actually a smaller tolerance than the 3.4%
of AT span in WCAP-11462 at nominal full power operation.
For the 4%
of computed AT to exceed 3.4% of the AT span the computed AT setpoint must be 85.9'F.
At nominal full power operation with stable conditions the computed overtemperature AT is approximately 79.5'F (1.18
- 67.4).
l
ATTACHMENT 1 (Continued)
Page 3' 3.
UFSAR References Provided below are UFSAR references that discuss overpower and overtemperature AT trips:
Table 7.2-3 lists the system accuracy for linearity and reproducibility as:
Overtemperature:
1 2*F and i 15 psi overpower:
1 2*F Section 7.2.1.1.9 references Table 7.2 for system
+
accuracies but does not describe the methodology used.
Section 14D.2 notes that a setpoint study was performed to simulate performance of the control and protection system.
WCAP-7795 "Setpoint Study for Duquesne Light.
Company Beaver Valley Unit 1"
discusses control and protection system sensitivities for gains and time constants but does~
not include a
discussion of instrument errors.
Sections 3.4.2.1 and 14D.4 note that the setpoints were calculated assuming approximately 15%
margin in the critical heat flux calculation.
Section 14D.4 notes that preliminary startup tests demonstrated that actual instrument errors are equal.to or less than the assumed values.
Sections 7.2.1.1.2 and 14 identify the overtemperature AT trip as protection against low DNBR-(DNBR > 1.3) and the overpower AT trip as protection against excessive power (kw/ft).
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