ML20028F484
| ML20028F484 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 01/25/1983 |
| From: | Broehl D PORTLAND GENERAL ELECTRIC CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| TAC-08291, TAC-42594, TAC-8291, NUDOCS 8302010386 | |
| Download: ML20028F484 (6) | |
Text
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Donald J. Brochl Assistant Vce Presdent January 25, 1983 Trojan Nuclear Plant Docket 50-344 License NPF-1 Director of Nuclear Reactor Regulation ATTN:
Mr. Robert A. Clark, Chief Operating Reactors Branch No. 3 Division of Licensing U. S. Nuclear Regulatory Commission Washington DC 20555
Dear Mr. Clark:
Containment Purging and Venting In our letters of October 2, 1981 and February 12, 1982, h;E committed to the replacement of the 8-inch hydrogen vent valves with valves qualified to the NRC guidelines dated September 27, 1979. Attached ic the quali-fication informatton for the Aplacement valves.
Sincerely, "a$$ '
Attachment c:
Mr. Lynn Frank, Director State of Oregon DW Department of Energy 8302010386 830125 PDR ADOCK 05000344 P
pon 121 S W Samen Spent. Penn. 0<egon 97204
E Trojan Nuclear Plant Robert A. Clark Docket 50-344 January 25, 1983 i
License NPF-1 Attachment Page 1 of 5
, HYDROGEN VENT VALVE QUALIFICATION INFORMATION The 8-inch hyr. ogen vent valves will be replaced during the 1983 refueling outage with valves qualified to the NRC guidelines of September 27, 1979.
The following information is provided to demonstrate the qualification of the replacement valves and actuators. The numbers correspond to the NRC guideline number in the clarification to the September 27, 1979 NRC letter.
1.
NRC Guideline: The aP across the valve is in part predicated on the Containment pressure and gas density conditions. What were the Containment conditions used to determine the A s across the valve at P
the incremental angle positions during the closure cycle?
PGE Response: A choked flow / static seismic test was performed on a 12-inch prototype valve to demonstrate operability for flow and load conditions simulating a Loss-of-Coolant Accident (LOCA). For conservatism, the test was performed with a constant AP of 65 psfi across the valve. This aP value is in excess of that expected during actual LOCA conditions.
2.
NRC Guideline: Were the dynamic torque coefficients used for the i
determination of torques developed, based on data resulting from actual flow tests conducted on the particular disc shape / design / size?
What was the basis used to predict torques developed in valve sizes i
different (especially larger valves) than the sizes known to have undergone flow tests?
l PGE Response:
Design torques for the 12-inch prototype valve were i
based on 3-inch scale model tests. The 12-inch bench test demon-strated that the design torques were conservative relative to measured to rq ue s.
Bench test and model testing data were compared and interpolated to predict torque characteristics for 8-inch valves.
3.
NPC Guideline: Were installation effects accounted for in the de'.ermination of dynamic torques ?eveloped? Dynamic torques are known.o be affected for example, by flow direction through valves with offset discs, by downstream piping back pressure, by shaft orientation relative to elbows, etc. What was the basis (test data or other) used to predict dynamic torques for the psrticu-lar valve installation?
PGE Response: The valve manufacturer has conducted model testing to demonstrate that installation effects are adequately accounted for j
in the determination of dynnmic torques.
Additional tests are in l
progress to demonstrate operability under many installed piping
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configurations. Model test data have been interpolated to predict dynamic torque ef fects for smaller valves for-the most conservative installation configuration.
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Trojan Nuclear Plant Robert A. Clark Docket 50-344 January 25, 1983 License NPF-1 Attachment Page 2 of 5 4.
NRC Guideline: When comparing the Containment pressure response profile against the valve position at a given instant of time, was the valve closure rate vs time (ie, constant or other) taken into account?
PGE Response: The Containment pressure response profile was not used in determining valve operability.
Rather, a constant AP was used as discussed in No. I above. This approach is more conservative.
5.
NRC Guideline:
Provide the necessary information for the table shown below for valve positions from the initial open position to the seated position (10* increments if practical).
Valve Position Predicted AP Maximum AP (in degrees - 90* = full open)
(across valve)
(capability)
PGE Response:
As discussed in No.1 above, the valve has been delanstrated operable for a constant AP of 65 paid and, therefore, predicted maximum AP values at incremental angle positions were more conservatively accounted for.
6.
NRC Guideline: What code, standards, or other criteria was the valve designed to? What are the stress allowables (tension shear, torsion, etc) used for critical elements such as discs, pins, shaf t r
yoke, ece, in the valve assembly? What load combinations were used?
PGE Response:
It has been specified that these valves shall be designed to ASME Section III, Class 2 requirements. The stress values and loadings shall also be in accordance with ASME Section III.
Seismic and dynamic loads were considered to occur simul-taneously. The 12-inch prototype valve bench : est demonstrated operability for a AP of 65 psfi while undergoing 11.0 g simulated seismic loadings applied in two perpendicular directions.
NRC Guideline Nos. 7 and 8 were omitted from the clarification provided to the September 27, 1979 letter.
9.
NRC Guideline:
For those valve assemblies (with air operators)....
ecc.
PGE Response:
The valves to be installed at Trojan will be equipped with motor operators.
10.
NRC Guideline: When air-operated valve assemblies use accumu-lators.... etc.
Trojan Nuclear Plant Robert A. Clark Docket 50-344 January 25, 1983 License NPF-1 Attachment Page 3 of 5 PGE Response: The valves to be installed at Trojan will be equipped with motor operators.
11.
NRC Guideline:
For valves assemblies requiring a seal pressuriza-tion system.... etc.
PGE Response: The valves to be installed at Trojan will not be equipped with a seal pressurization system.
12.
NRC Guideline: Describe the modification made to the valve assembly to limit opening angle. With this modification.... etc.
PGE Response: The valves to be installed at Trojan will be operable through the full range of motion and will not be required to have a limited opening angle.
13.
NRC Guideline: Does the maximum torque developed by the valve during closure exceed the maximum torque rating of the operators?
Could this affect operability?
PGE Response: The operators for the valves will be sized such that the maximum torque required to shut the valves during LOCA conditions will be within the capability of the operators.
14.
NRC Guideline: Has the maximum torque value determined in No. 13 been found to be compatible with torque limit settings where applicable?
PGE Response: The torque required to close the valves under accident conditions will not exceed the torque limit switch settings.
15.
NRC Guideline: Where electric motor operators are used, has the minimum available voltage to the electric operator under both normal and emergency modes been determined and specified to the operator manufacturer to assure the adequacy of the operator to stroke the valve at DBA conditions with these lower-limit voltages available?
Does this reduced voltage operation result in any significant change in stroke timing? Describe the emergency mode power source used.
PGE Response:
PGE has specified that the motor torque et 80 percent voltage shall be capable of overcoming the maximum AP across the seat of the valve, taking into account friction due to valve packing. The motor operator will be capable of fully opening or closing the valve against this AP within three seconds. The emergency power supply for these valves is the diesel generators.
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Trojan Nuclear Plant Robert A. Clark Docket 50-344 January 25, 1983 License NPF-1 Attachment Page 4 of 5 16.
NRC Guideline: Where electric operator units are equipped with handwheels, does their design provide for automatic reengagement of the motor operator following the handwheel mode of operation? If not, what steps are taken to preclude the possibility of the valve being left in the handwheel mode following some maintenance, test, j
etc, type operation?
1 PGE Response: The electric operator units are equipped with hand-wheels for manual operation of the valve.- When the electric motor is engaged, the handwheel is disengaged. Af ter handwheel operation, the electric motor is automatically reengaged.
- 17. NRC Guideline:
Describe the tests and/or analysis performed to j
establish the qualification of the valve to perform its intended function under the environmental conditions exposed to during and after the DBA following its long-term exposure to the normal plant environment.
PGE Response:
In addition to the operability test of a 12-inch valve under pressure, flow, and loadings simulating operating and seismic conditions possible during a LOCA, seat leakage tests were performed to demonstrate leak tightness of the valve using metal-to-metal sealing in lieu of elastomer seals. The metal-to-metal sealing was demonstrated to improve with age of the valve. The test showed sealing improved continuously up to 41,000 cycles, the limit of the test.
The effects of debris on sealing capability of the valve was also tested. The test showed the valve could tolerate some large de!. tis and still maintain a relatively low leakage, even with a damaged l
seal. The debris used in the teet will not pass through the protective debris screens at Trojan. Additionally, the valve demonstrated good sealing characteristics under varying temperatures from the cryogenic range to 900*F.
18.
NRC Guideline: What basis is used to establish the qualification of the valve, operators, solenoids, valves? How was the valve assembly l
Ivalve/ operator) seismically qualified (test, analysis, etc)?
i PG2 Response: Valve / operator qualification has been based on test data, analyses, or a combination of these. Analyses have becu performed to demonstrate the applicability of generic test dt a when required. During dynamic operability testing of the 12-inch proto-type valve with am air operator, static loads simulating 11.0 g seismic load were applied. Additionally, resonant frequency testing of the 12-inch valve assembly was performed, verifying seismic l
f requency analysis for a range of 1-40 Hz.
These tests, along with generic seismic test data for the motor operator to be supplied with the valve, will ne analyzed and a final seismic qualification report will be issued by the valve vendor.
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Trojan Nuclear Plant Robert A. Clark Docket 50-344 January 25, 1983 License NPF-1 Attachment Page 5 of 5 19.
NRC Guidelines Where testing was accomplished, describe the type tests performed, conditions used, etc.
Tests (where applicable) such as flow tests, aging simulation (thermal, radiation, wear, vibration endurance, seismic), and LOCA-DBA environment (radiation, steam, chemical) should be pointed out.
PGE Response:
Dynamic valve testing under DBA-LOCA conditions are described under Nos. I and 17 above. Valve materials were selected such that they would not be susceptible to radiation, steam, or chemical environments expected during a LOCA. There are no elasto-meric materials used in these valves.
A generic type test report is available for the valve operator, which demonstrates qualification for a DBA-LOCA environment.
An evaluation will be performed to substantiate the applicability of this report to the valve actuators being supplied with the valves.
20.
NRC Guideline: Where analysis was used, provide the rationale used to reach the decision that analysis could be used in lieu of testing.
Discuss conditions, assumptions, other test data, handbook data, and classical problems as they may apply.
PGE Reaponse:
Analyses performed to demonstrate valve / actuator qualification are supported by test data from model or operability testind. Analysis alone was not used in qualifying these valves.
21.
NRC Guideline: Have the preventative maintenance instructions (part replacement, lubrication, periodic cycling, etc) established by the manufacturer been reviewed, and are they being followed? Considera-tion should especially be given to elastomeric components in valve body, operators, solenoias, etc, where this hardware is installed inside containment.
PGE Response: Valve / actuator maintenance and instruction manuals will be provided with the new valves. The manufacturers' maintenance instructions will be implemented at that time.
SAB/4sjelB18
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