IR 05000280/1990032
| ML18153C430 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 11/02/1990 |
| From: | Belisle G, Julian C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18153C429 | List: |
| References | |
| 50-280-90-32, 50-281-90-32, NUDOCS 9011160113 | |
| Download: ML18153C430 (4) | |
Text
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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REGION II
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101 MARIETTA STREET, ~
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ATLANTA, GEORGIA 30323 *
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Report Nos.:
50-280/90-32 and 50-281/90-32 Licensee:
Virginia Electric -nd Power Company Glen Allen, VA 23060 Docket Nos.:
50-280 and 50-281 Facility Name:
Surry 1 and 2 License Nos.: DPR-32 and. DPR-37 Inspection Conducted: _ O~ob)J 9-11,. \\990
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',/ /,2 J Inspector:
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G. A. Bel fsle. -
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Accompanying Personnel:
A. E. Levin Approved by: C A *. *~1 C. A. Julian, Chie Engineering Branch Division of Reactor Safety SUMMARY Scope:
Date 'S7i gned
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Date Signed This routine, announced inspection was conducted in the areas of reviewing the licensee's calculations and test procedures for determining flow through the recirculation spray heat exchangers (RSHXs).
Results:
In the areas inspected, violations or deviations were not identifie The licensee made basic engineering mistakes in the calculation for determining which RSHX train to tes These mistakes, however, did not significantly impact the result The calculation for*determining RSHX fouling appeared adequate (paragraph 2).
The special test to determine RSHX flow appeare adequate (par~graph 2).
9011160113 901102 PDR ADOCK 05000280 Q
PNU
,,, Persons Contacted Licensee Employees REPORT DETAILS
- W. Benthall, Supervisor, Surry Licensing R. Cherry, Licensing A. Hall, System Engineer J. Kelly, System Engineer J. Niland, Project Engineer J. Pak~ Nuclear E~gineering Services
- A.-Price, Assistant Station Manager R. Rasnic, Nuclear Engineering Services J. Waddill, Nuclear Engineering Services S. Wiser, Nuclear Engineering Services
- T. Towers, Superintendent of Engineering Other licensee employees contacted during this inspection included engineers, operators, and administrative personne NRC Resident Ins~ectors
. *S. Tingen, Resident Ins~ector
- Attended exit interview Acronyms and initialisms used throu~hout this report are listed in the,
last paragrap.
RSHX Testing (61701)
VEPCO calculation ME-0262, Equivalent Length Comparison of Service Water Piping to Recirculation Spray Heat Exchangers, Revision 0, was performed to show that the single train of RSHX scheduled for service water flow testing was representative of the four trains at Surry (two for Unit 1, two for Unit 2).
The comparison was performed by converting a 11 service *
water piping, valves, fittings, and the heat exchangers themselves to equivalent lengths of 24-inch OD pipin The conversion was done by first determining the equivalent lengths of all fittings and valves at their actual diameters in accordance with conventional length-to-diameter ratios (such as those published in the Crane manual), and then using a pressure drop equation to calculate the length of 24-inch OD pipe that would result in an equal pressure drop for the same volumetric flo A similar conversion was done for the RSHXs using specifications data from the heat exchanger manufacture **
The inspectors review of this calculation found that the conversion of pipe lengths was not done properly because it -oini tted the effect of changing the pipe diameter on the friction factor for the pip Furthermore, the inspectors also discovered that, in determining the overall equivalent length of 24-inch OD piping for each RSHX* train, para 11 el branches of piping had been added together as if they were in series, giving erroneous answer These errors were brought to VEPCOs attention by telephone and were discussed further onsite on October During the discussion on October 9, VEPCO admitted that errors had been made, but claimed that the impact of the errors on the conclusions reached by means of these calculations were minima The inspectors-agreed that the errors did not affect the conclusions reached, but expressed concern about the abi 1 i ty of VEPCO I s engineering staff to do fundamenta 1 fluid mechanics calculations.properl VEPCO stated that a modification of the original calculation was being prepared to correct these error An additional meeting was conducted on October 10 to discuss the modification and to resolve any remaining difference During this meeting, VEPC0 1s modified approach was examined; VEPCO engineers attempted to calculate directly the pressure drop for each RSHX train properly accounting for different pipe si.zes and parallel branche However, additional errors were found in this revised calculation, stemming from VEPCOs failure to account for changes in velocity with changes in pipe diameter The friction factors. and effective resistance terms were calculated correctly, but, rather than account individually for each different pipe diameter, a 11representative 11 diameter of 36 inches was chosen, and the velocity in that pipe was used for all pipe pressure drop calculation This error was brought to the attention of the VEPCO e.ngi neers and, after extended discussions, VEPCO.agreed that the calculation would be redone from the*
beginning in a rigorous manne *
The inspectors conclusion drawn from ME-0262 was that the RSHX train*
scheduled for testing was representative of those in the two unit The inspectors also concluded that the calculation demonstrated that ample flow would be available to meet RSHX service water-side requirement The errors found in the ME~0262 and its revisidns did not invalidate the above conclusions; however, VEPCO should be especially careful in these types of calculations to follow fundamental fluid mechanics principles* in developing estimates for the perform~nce of thermal-hydraulic system.
.
The inspectors reviewed ME-0266, Evaluation of Recirculation Spray Heat Exchangers, Revision 2. This calculation was.developed to model the -RSHXs and assess their ability to remove long term DBA heat loads under microfouling conditions. This ~alculation concluded that the RSHXs can be effectively 20 percent blocked after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and 80_percent blocked after-30 days and still remove containment heat load An allowable rate of macrofouling was also calculate The inspectors concluded that this calculation, after discussion with VEPCO personnel to resolve questions, was acceptabl. -.
The inspectors reviewed I-ST-90, Recirculation Spray Heat Exchangers Source Water Flow Test, Revision 0, and subsequent procedure change, Number 90-13 The purpose of this test was to collect data in 6rder to determine that the DBA flow and long term cooling is adequate to reject design basis heat loads from containmen The other purpose of this test was to collect data necessary to validate pressure drop values provided by the manufacturer and estimate reduction in heat transfer capability due to macrofouling. This test appeared adequat *
Within this area, no violations or deviations were identifie.
Exit Interview
_The inspection scope aria results were summarized on October 11, 1990, with those persons indicated in paragraph The inspector described the areas inspected and discussed in detail the inspection result Dissenting comments were not received from the license.
Acronyms and Initialisms OBA NRG OD RSHX.
SR VEPCO Design Basis Accident Nuclear Regulatory Commission Outside Diam~ter Recirculation Spray Heat Exchanger Special Test Virginia Electric and Power Company