ML20150F246
| ML20150F246 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 07/11/1988 |
| From: | Robert Williams PUBLIC SERVICE CO. OF COLORADO |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| IEB-88-004, IEB-88-4, P-88236, TAC-69917, NUDOCS 8807180197 | |
| Download: ML20150F246 (5) | |
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P.o. Box 840 Denver, Co 80201@40 R.O. WILLIAMS, JR.
July 11, 1988 IvedIn*okboss Fort St. Vrain Unit No. 1 P-88236 U. S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Docket No. 50-267
SUBJECT:
Initial Response to NRC Bulletin 88-04 (G-88152)
Gentlemen:
Public Service Company of Colorado (PSC) has evaluated NRC Bulletin 88-04, "Potential Safety-Related Pump Loss", for applicability to the Fort St. Vrain (FSV) Nuclear Generating Station. This correspondence provides the initial response for each item as addressed below.
NRC Item 1:
Promptly determine whether or not your facility has any safety-related system with a pump and piping system configuration that does not preclude pump-to-pump interaction during miniflow operation and could therefore result in dead-heading of one or more of the pumps.
PSC Response:
Safety-related pump / piping system configurations at FSV have been evaluated for the potential of dead-heading centrifugal pumps during parallel operation.
PSC has determined that parallel operation while on minimum flow does not represent a concern at FSV due to flows being relatively high on the respective centrifugal pump efficiency curves for the pumps that are used for parallel operation. However, due to differing understardings of the scope of Bulletin 88-04, vertical turbine pumps were not initially evaluated.
They are presently being analyzed, and with the NRC Tschnical Contact's concurrence, final response is scheduled for September 8, 1988, due to the current maintenance outage and the need for vendor interface.
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NRC Item 2:
If the iituation described in Item 1 exists, evaluate the system for flot division taking into consideration (a) the actual line and component resistances for the as-built. configuration of the identified system; (b) the head versus flow characteristics of the installed pumps, including actual test data for "strong" and "weak" pump flows; (c) the effect of test instrument error and reading error; and (d) the worst case allowances for deviation of-pump test parameters as allowed by the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)
Section XI, Paragraph IWP-3100.
PSC Response:
The situation described in Item 1 does not exist at FSV for the centrifugal pumps analyzed.
The final response for vertical turbine pumps will be provided on September 8, 1988.
NRC Item 3:
Evaluate the adequacy of the minimum flow bypass lines for safety-related centrifugal pumps with respect to damage roulting from operation and testing in the minimum flow modt. This evaluation should include consideration of the effects of cumulative operating hours in the minimum flow mode over the lifetime of the plant and during the postulated accident scenario involving the largest time spent in this mode. The evaluation should be based on best current estimates of potential -pump damage from operation of the specific pump models involved, derived from pertinent test data and field experience on pump damage. The evaluation should also include verification from the pump suppliers that current miniflow rates (or any proposed nodifications to miniflow systems) are sufficient to ensure that there will be no pump damage from low flow operation.
If the test data do not justify the existing capacity of the bypass lines (e.g., if the data do not come from flows comparable to the current capacity) or if the pump supplier does not verify the adequacy of the current miniflow capacity, the licensee should plan to obtain additional test data and/or modify the provide a miniflow capacity as needed.
PSC Response:
Minimum flow bypass lines have been evaluated for safety-related centrifugal pumps at FSV. The vendor for the two centrifugal pumps (P-2103, P-2103-S) that were initially considered as needing further evaluation was contacted and has specified a
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Page 3 July 11, 1988 minimum flow rate that is consistent with the installed configurationsand actual recirculation ' mode.
Therefore, no further actions are necessary with regard to the analyzed ~
l centrifuga1' pump configurations.
The final response will be provided on September 8, 1988.
NRC Item 4:
Within 60 days of receipt of this bulletin, provide a written response that (a) summarizes the problems and the systems
- affected, (b) identifies the short-term and long-term modifications to plant operating procedures or hardware that have being implemented to ensure safe plant operations, been or are (c) identifies an appropriate schedule for long-term resolution of this and/or other significant problems that are identified as a result of this bulletin, and (d) provides justification for continued operation particularly with regard to General Design Criterion 35 of Appendix A to Title 10 of the Code of Federal Regulations (10 CFR 50),
"Emergency Core Cooling" a'nd 10 CFR 50.46, "Acceptance Criteria for Emergency Core Cooling System for Light Water Nuclear Power Reactors."
PSC Response:
This correspondence fuifills the initial 60-day reporting requirement.
Subsequent discussion with the NRC Technical Contact. has shown the need to evaluate vertical turbine pumps in-addition to the centrifugal pumps analyzed for the initial response to Bulletin 88-04.
PSC will fully respond with information on vertical turbine pumps on September 8, 1988, due to the plant being in a planned maintenance outage and the need for vendor interfsce.
1 NRC Item 5:
Within 30 days of completion of the long-term resolution actions, provide a written response describing the actions taken.
1 PSC Response:
1.ong-term resolution actions are not required at FSV, for the centrifugal pumps presently analyzed. The final response to Item 5 will be reported on September 8, 1988 for the remaining pumps.
NRC item 6:
An evaluation of your actions in response to this bulletin should be documented and maintained at the plant site for a minimum of two (2) years. That evaluation should, as a minimum, address the
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piping system configuration in accordance with Item 1 above, each of the four factors discussed in Item 2,. pertinent test data and field experience on minimum flow operation, and verificatfon of
'the adequacy of current miniflow capacity 'by the pump manufacturer.
PSC Response:
The initial evaluation will be-maintained under memorandum NFS-88_-0288, dated June _ 30, 1988, with the subsequent evaluation to be reported on September 8, 1988.
If there are any questions, please contact Mr. M. H. Holmes at (303) 480-6900.
Very truly you s, b
R. O. Williams, Jr.
Vice President Nuclear Operations R0W/WMD:dvd cc:
Regional Administrator, Region IV ATTN: Mr. T. F. Westerman, Chief Projects Section B Mr. Robert Farrell Senior Resident Inspector Fort St. vrain e
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_s UNITED STATES.0F AMERICA NUCLEAR REGULATORY COMMISSION In the Matter Public Service Company of Colorado
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Docket No. 50-267 Fort St. Vrain Unit No. 1
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AFFIDAVIT R.
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- Williams, Jr., being first duly sworn, deposes and says:
That he is Vice President, Nuclear Operations, of Public Service Company of Colorado, the Licensee herein, that he has read the foregoing information and knows the contents thereof, and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
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O'. W i l l i ams, fr.
Vice President fluclear Operations STATE OF
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COUNTY OF 24,o 6 6 Subscribed and sworrr ore me, a Notary Public on this
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, 1988.
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My commission expires 9- /9
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