ML20132F807
| ML20132F807 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 07/31/1985 |
| From: | Mittl R Public Service Enterprise Group |
| To: | Butler W Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8508020393 | |
| Download: ML20132F807 (6) | |
Text
. -.
Pud:c Service PS G Compar.y
-l E!ectnc and Gas 80 Park Plaza, Newark, NJ 07101/ 201430-8217 MAILING ADDRESS / P.O. Box 570, Newark, NJ 07101 Robert L. Mitti General Manager Nuc' ear Assurance and Regulation July 31, 1985 Director of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, MD 20814 Attention:
Mr. Walter Butler, Chief Licensing Branch 2 Division of Licensing Gentlemen:
RESPONSE TO THE NRC REQUEST FOR ADDITIONAL INFORMATION (RAI)
SAFETY PARAMETER DISPLAY SYSTEM (SPDS) ISOLATION HOPE CREEK GENERATING STATION DOCKET NO. 50-354 Enclosed for NRC staf f review, please find the Public Service Electric and Gas Company (PSE&G) item-by-item response to the subject RAI regarding SPDS isolation discussed in the May 1985 telecon.
Please note that the detailed reports referenced in responses to items 2.a, 2.b, 2.c, and 2.d will be available for NRC review in mid-October 1985.
This information is pertinent to Hope Creek Safety Evaluation Report (SER) Outstanding Issue 15.
Should there be any questions or concerns on this matter, please do not hesitate to contact us.
Very truly yours, MNbtA/gp fm yo\\
Enclosure M P85 139/14 1-dh The Ener9Y People 8508020393 850731 PDR ADOCK 05000354 F
- 9gy,
. Director of Nuclear Reactor.
2 7/31/85 Regulation.
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.D. H. Wagner
.USNRC Licensing Project Manager
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A. R. Blough' i
USNRC Senior Resident Inspector i
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~ - Response to NRC Request for Additional Information on SPDS Isolators NRC Item No. 1 "The SPDS safety systems shall be suitably isolated from electrical or electronic interference with equipment and sensors that are in use for safety systems."
Response
The HCGS SPDS interfaces with Class lE safety-related cir-cuits via qualified isolation devices.
All isolation devices used at HCGS to interface between safety-related Class lE circuits and non-safety-related circuits are described in the response to FSAR Ouestion 421.13.
Those isolators used in SPDS interfaces are described in parts (b), (c.3), and the optical isolation device description of 4
the NSSS part of the question response.
NRC Item No. 2.a "For each type of device used to accomplish electrical iso-lation at (HCGS), describe the specific testing performed to demonstrate that the device is acceptable for its applica-tion (s).
This description should include elementary diagrams, where necessary, to indicate the test configura-tion and how the maximum credible faults were applied to the devices."
Response
General descriptions of the testing performed on each isola-tion device are provided in the response to FSAR question 421.13.
Detailed descriptions of the testing performed are contained in the test procedures / reports provided by the vendor performing the testing.
The response to FSAR ques-tion,421.13 will be revised to provide test report references as they become available.
NRC Item No. 2.b
" [ Provide } data to verify that the maximum credible faults applied during the test were the maximum voltage / current to which the device would be exposed and how the maximum voltage / current was determined."
M P85 139/14 3-dh
a
. Response The response to FSAR Question 421.13 will be revised to include the calculated maximum credible " hot short" voltage and short circuit current values for each isolation device.
The following description of how these fault values were calculated will also be included in the revised question response.
Maximum credible " hot short" voltage and short circuit current calculation methodology:
A.
Assumptions:
1.
Maximum " hot short" voltage conditions occur when the phase conductors of one cable become faulted with the phase conductors of a higher voltage cable without shorting to ground.
2.
Maximum " hot short" voltage conditions and short circuits (to ground) do not occur simultaneously.
3.
Maximum short circuit current is based on maximum connected source voltage and cable impedance.
4.
None of the non-Class lE electrical protection devices (i.e.,
fuses, circuit breakers, etc.)
function to remove the fault identified in assumption 3.
5.
Cable impedance is based on temperature at 10'C for conservatism.
Actual temperature is expected to be higher, which would result in lower short circuit currents than those calculated at 10'C.
B.
Maximum credible " hot short" voltage calculation methodology:
1.
The adjacent cable with the highest voltage poten-tial that could be shorted to the cable of concern is determined from engineering drawings.
2.
A 10 percent factor representing nominal voltage fluctuations is then added to the voltage potential of the cable identified in Step 1.
M P85 139/14 4-dh l
. 3.
The maximum credible " hot short" voltage is then calculated by adding the fault voltage obtained in Step 2 to the nominal voltage of the cable of concern.
C.
Maximum credible short circuit current calculation methodology:
1.
Calculate the maximum voltage from the normal source by summing the rated voltage, the voltage due to nominal voltage fluctuations, and where applicable, the voltage due to transformer tap fluctuations.
2.
Calculate the cable impedance by multiplying the length of the cable of concern (actual constructed length or 95 percent of engineered length, if actual constructed length is not available) by the imped-ance per length value (based on 10*C) obtained from the manufacturer's specifications for the particular cable type and size.
3.
The maximum credible short circuit current is then calculated by dividing the maximum voltage value obtained in Step 1 by the cable impedance value obtained in Step 2.
The test report for each isolation device will identify that the device was tested to these calculated (or higher) fault values.
NRC Item No. 2.c
" [ Provide] data to verify that the maximum credible fault was applied to the output of the device in the transverse mode (between signal and return) and other faults were considered (i.e., open and short circuits)."
Response
The test report for each isolation device will identify that the maximum credible " hot short" voltage and short circuit current faults were applied in transverse mode.
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J NRC Item No. 2.d
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" Define the PASS / FAIL: acceptance cr'it eria for each type of device."
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Response
The PASS / FAIL criteria will be defined in the test procc5dre for each isolatiyn device; The basic PASS / FAIL criteria is that no credible fault on the non-Class lE side (includiny maximum credible " hot short" voltage and short circuit cur-rent faults) will cause misoperations or degradation of operation on the Class 1E (safety-related) side of the isolation device =.
NRC Item No. 2.e
" Provide a commitment that the isolation devices comply with the environmental qualifications (10CFR50.49 and tha. seismic qualificiations which were the' basis for plant licpnsing."-
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Response
s The environmental.ind seismic' qualification requirements for each isolation deOice are identified in the response to FSAR Ouestion 421.13.
NRC Item No. 2.f
" Provide a ~ desbription of thermeasures to protect 'the safety systems from electrical inteiference (i.e.,
Elec' rosta' tic c
Coupling, EMI, Common Mode, an& Crosstalk) that may be generated by the SPDS."
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Response
i The. electrical inte'rference testing performed on each isola-tion device is identified in the response to FSAR Ouestion 421.13.
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