ML20198R345
| ML20198R345 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 11/05/1997 |
| From: | Barron H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9711130244 | |
| Download: ML20198R345 (9) | |
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Duke Fower Company W},'
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November 5, 1997 Document Control Desk US Nuclear Regulatory Commission Washington, D.C.
20555 Subjects-McGuire Nuclear Station, Units 1 and 2 Docket Nos 50-369 and 50-370 Proposed Technical Specification Amendment Technical Specification Table 3.3-4 (ESF Trip Setpoint)
Request for Additional Information Dear Sir On October 13, 1997, Duke Energy Corporation (Duke) submitted a proposed Technical Specification Amendment package to revise an ESF trip.cetpoint for ECCS switchover.
An expedited review and approval by the NRC was requested by Duke to allow for implementation during the current refueling cutage.
During NRC review of the package, questions that needed immediate answers were generated.
A conference call was conducted on October 30, 1997, between the NRC and Duke and questions developed by the NRC were discussed.
Written summaries of Duke's responses to NRC questions are provided in the attachment.
There are no regulatory commitments contained in this transmittal.
If there are any questions concerning this amendment request or should additional information be required, pleese contact Virginia Owen at-(704)875-5113.
Very truly yours, t
IDDl H. B..Barron, Vice President
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j McGuire Nuclear Station Duke Energy Corporation h
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t US Nuclear Regulatory Commission November 5, 1997 Page 2 xc Mr. Luis A. Reyes Administrator, Region II US Nuclear Regulatory Commission Atlanta Federal Center.
61 Forsyth St.,
SW, Suite 23T85 Atlanta, GA 30303 Mr. Victor Herses US Nuclear Regulatory Commission office of Nuclear Reactor Regulation (14H25)
Washington,-D.C. 20555 Mr. Scott M. Shaeffer NRC Senior Resident Inspector McGuire Nuclear Station Mr. Richard M. Fry, Chief Division of Radiation Protection State of North Carolina 3825 Barnett Drive Raleigh, N.C.
27609-7221
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- US Nuclear Regulatory Commission l
Nbvember 5, 1997 i
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bxc: E. Mac Geddin J. W. Boyle P. R. Herran G. A. Copp (EC050 ).
M. S. Kitlan (CN01RC)
J.'E. Burchflold (ON01RC)
J. W. Piteua V. S.
Owen' W. R. Cross K. L.. Crane P. T. Vu J. M. Washam P. R. Newton (PB05E)
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CONFERENCE CALL OF 10/30/97
'i BETWEEN NRC AND NCGUIRE NUCLEAR STATION RE: PROPOSED TECENICAL SPECIFICATION REVISION i'
TABLE 3.3-4 (ESF TRIP SETPOINT)
QUESTIONS / ANSWERS
- 1) Provide a discussion of how the nonsafety related wiring to the enclosures and in the enclosures is separated from the safety related wiring.
Include in this discussion detailed schematics of the three FNST level instrument I
enclosures, including wiring penetrations and component locations for the level instrument, the two heaters, and the associated instrumentation and controls.
Response
Enckground Informations Currently, the three safety related FWST level transmitters are mounted inside three separate enclosures between the FWST and the FWST missile wall.
The temperature is very difficult to regulate inside of the enclosures because of their size (24"H x 20"W x 12"D).
The new design will relocate all of the level instrumentation inside one heated room between the FWST and the FWST shield wall (see Figure 1).
The room is approximately 14 feet high, 20 feet long, and 4 feet wide.
There is adequate space in this room to allow ease of instrument maintenance.
The new room will be insulated and heated.
Two completely independent space heaters will be provided to heat the room.
The space heaters are sized such that only one is required to maintain the temperature in the room between 60' F and 70* F with an outside temperature of
-5' F (the lowest outside temperature of
-5' F is based on FSAR Table 2-9).
One heater is provided as the primary heater and another as a backup.
The primary heater temperature control switch is set to turn the space heater on at 60* F and off at 70* F.
In the event that the primary heater fails, the backup heater is set to turn on at 48' F and of f at 70* F.
If the-temperature inside the new room reaches 50' F, the plant computer will alert the operators of a low temperature condition.
This is indication that the primary heater has failed or is I
unable to maintain the room temperature.
At this point, the operators will be instructed to investigate the situation.
If necessary, additional space heating can be provided to increase the room temperature.
Three GFI receptacles are provided inside the new room and can be used to power temporary space heating if required.
Relocating the instruments inside of this new room also significantly decreases the amount of impulse tubing exposed to the outside environment.
Each safety related tranamitter will only have about 8 feet (a total of 24 feet for all three safety related transmitters) of tubing extending outside of the heated room (currently, there is a total of approximately 120 feet of impulse tubing exposed to the (.vironment that requires heat tracing).
Sections of impulse tubing exposed to the outdoor environment will be heat traced utilizing redundant heat trace controllers.
Jaswert Figure 1 (attached) provides an illustration of equipment layout and cabling inside the new FWST instrument room.
The safety related transmitter cabling runs from inside the plant to an area between the FWST and FWST shield wall via an underground cable trench.
This modification only affects the safety related transmitter cabling from the point where the cabling exits the cable trench inside the FWST missile wall up to the new transmitter location.
The following discussion only pertains to the separation of sections of cabling affected by this modification.
Separation between safety and non-safety related cabling affected by the subject modification was designed in accordance with Duke Power Electrical Discipline Design Manual, Section DC-1.01. Revision 16.
Separation of the redundant safety relatem cabling complies with section 6.3 of DC-1.01, which specifies a minimum of 18 inches separation between redundant safety related cables without additional' protection or 12 inches with an approved fireproof barrier between them.
The redundant safety related cables affected by this modification are separated by a distance greater than 18 inches.
Addit.lonally, each safety related cable is routed in conduit which is considered a fireproof barrier. There are no safety related cables run with non-safety related cables for this modification.
The nearest non-safety related cable is approximately 18 inches from the safety related cabling (this non-safety related cable is routed 2
in rigid conduit and is used to supply 110 VAC power to t
the new room receptacles).
Space heater power cables are routed approximately 3 feet from the safety related transmitter cables.
In summary, the separation of safety related cabling and non-safety related cabling meets or exceeds the requirements outlined in Duke Power Design Criteria DC-l 1.01.
- 2) Nou has the licensee ensured that no more than one channel can be removed from service at a time?
Response
There are administrative controls within existing procedures that do not allow more than one channel to be removed from service at any one time during modes 1 through 3.
The procedures contain specific caution 1
statements that prohibit multiple channels out of service.
The procedures also contain specific steps directing personnel to obtain approval from the control room SRO before removing equipment from service to further ensure that no more than one channel is removed from service at a time.
Placing a FWST level channel into TEST (to perform the monthly analog channel operational test) illuminates an annunciator on the 1.47 Bypass panel.
- 4) How is manual bypassing of a FWST channel accomplished?
Is access to the bypass capability under the licensee's administratise control?
When a channel is bypassed, is the bypass status indicated in the NCR7
Response
There are no manual bypass switches.
Individual channel testing provides a means of manual bypass.
Each channel contains a test switch which substitutes a potentiometer in the circuit for the level transmitter.
When the channel is placed into test (i.e. for the analog channel operational test), status of this test condition for that channel is illuminated in the control room through 1.47 Bypass indication.
- 5) Has the licensee evaluated the seismic response spectra of the new instrument installation?
The Rosemount 1153D weighs about 24 lbm.
How is the instrument connected to the FWST?
Can the sensing lines be broken during a DBE?
3
the FWST?
Can the sensing lines be broken during a DBE7
.The instrument itself is qualified for 70, but the instrument installation on the FWST must be evaluated.
Responset The seismic response spectra of the new instrument installation was evaluated using Duke Power Specification MCS-1108.00-00-0002 (Specification For The Response Spectra and Seismic Displacements For Category I Structures).
The safety related level instruments are mounted to the inside of the FWST missile wall which consists of 24
. inches of reinforced concrete. The additional weight of e equipment added to the missile wall will have a negligible effect on the seismic response of the missile wall. In addition, the seismic qualification of the new safety related level transmitters envelope the design acceleration calculated for the FWST structure.
Level instrument impulse tubing extends from the instrument location on the concrete missile wall to the instrument taps at the tank.
1 The three sensing lines that extend from the FWST to the safety related level instruments will be routed in a tube support designed in accordance with ANSI /ISA Standard S67.02-1980, Section 5.2.
This is necessary due to the difficulty in maintaining the separation requirement between the three redundant instrument lines. Note that the area between the FWST and FWST shield wall is not considered a hostile environment because the area is not subject to high energy jet streams, missiles, or pipe whip.
The instruments arn mounted seismically as specified in Duke Power installation specification MCS-1210.05 0038.
- 6) Unlike the existing configuration, non-Class lE electrical devices (heaters and associated wiring) will be inside the instrument enclosures.
Has the licensee evaluated the electromagnetic environment and its effect on the new instrumentation?
These evaluations apply for both noise susceptibility and emissions.
Has the local FWST environment been evaluated for susceptibility and maissions of electromagnetic interference (EMI) in accordance with the NRC approved EPRI Quideline TR-102323?
4
Response
Each existing safety related level transmitter is currently mounted inside of a 24"H x 20"W x 12"D metal box and between the FWST and the FWST missile wall.
Inside each of these boxes are the safety related level transmitters, transmitter cabling, enclosure heaters and associated cabling, thermostats, and temperature switches that are used for alarming purposes.
An evaluation of the electromagnetic environment in the new instrumentation area (see Figure 1) has not been performed.
However, this modificatiot does not introduce any new EMI emissions in the ?.ocation between the FWST and FWST missile wall.
Review.)f EPRI Guideline TR-102323 for the modification has been performed.
Equipment and cable separation requirements as specified in this report are met.
EMI associated with the new transmitters may be reduced as a result of this modification because the separation between the safety related level transmitters and the space heating equipment will be significantly increased as compared to the existing level instrument enclosures.
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