ML20137Z753
| ML20137Z753 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 04/10/1997 |
| From: | Barron H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9704250107 | |
| Download: ML20137Z753 (8) | |
Text
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DUKEPOWER April 10,- 1997 U. S. Nuclear' Regulatory Commission Attention: Document Control Desk Washington, DC 20555
Subject:
McGuire Nuclear Station, Units 1 and 2, Docket Nos.-50-369 and 370 Supplement to Containment Purge Proposed TS Amendment l
By letter dated January 6, 1997, Duke Power Company submitted a
-proposed one-time revision to McGuire Units 1 and 2 Technical Specifications.
The proposed change would allow operation of the Containment Purge Ventilation System during Modes 4 and 3 during
'the startup from each respective steam generator replacement
[
outage.
On March 3, 1997, a conference call was held with representatives of the NRC Staff and Duke Power Company.
It was requested that Duke provide follow-up responses to a number of questions from the. Staff.
Responses to each of these questions is provided in
. Attachment 1.
]
On March 12, 1997, a conference call was held with l
representatives of the NRC Staff and Duke Power Company, i
Responses to each of these questions is provided in Attachment 3.
This letter contains the following Commitments:
- 1. UFSAR Section 15.6.5.3 will be updated. (Attachment 1) i
- 2. Either VP train used for Containment purging in Modes 4 and 3 will have an operable filter. (Attachment 2)
- 3. The VP valves that will be used for Purging in Mo' des 4 and 3 will be tested prior to entry into Mode 4.
l (Attachment 3) go?A'I 9704250107 970410~
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PDR ADOCK 05000369 h-P PDR ll ll ll Ill ll lllll
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U.
S.. Nuclear Regulatory Commission April 10, 1997 Page 2 Please contact R.
O.
Sharpe at (704) 382-0956 if you have any questions.
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Very truly yours, H.
B.
Barron Attachment i
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U.
S. Nuclear Regulatory Commission April 10, 1997 Page 3 xc:
L.
A.
Reyes, Regional Administrator U.
S. Nuclear Regulatory Commission, Region II 101 Marietta Street, NW, Suite 2900 l
Atlanta, GA 30323 S. M.
Shaeffer Senior Resident Inspector McGuire Nuclear Station V.
Nerses Project Manager, ONRR i
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4 McGuire Nuclear Station Response to NRC Staff Questions Containment Purge During Modes 4 and 3 Question 1 - Why was containment release modeled as a release through the Annulus Ventilation System ?
Response - Prior to initiating containment purging in Mode 4, containment integrity will be established per Tech Spec 3.6.1.1.
With the Containment Purge valves open, the most likely leak path in the event of a LOCA would be through the Containment Purge System (VP).
Due to limitations of the current Duke, McGuire model, a containment release through the VP System is not allowed by the model.
This event is therefore modeled by releasing the source term at the start of the event.
No credit was taken for the time required for the decay heat to cause the fuel to melt; this time is approximately 100 minutes.
The source term is released to lower containment.
Activity is transported to upper containment via the ice condenser.
No credit is taken for iodine removal in the ice condenser.
Activity is then transported to a volume equivalent to 1% of the annulus volume and released outside containment via filters.
Additionally a transport path is modeled which bypasses the reduced annulus volume and filters.
The release through the Annulus filters is modeled to represent a release through the Containment Purge filters.
Additional description of the model is provided in Attachment 2.
Question 2 - The iodine removal efficiencies are misstated in the discussion of calculation MCC-1227.00-00-0064, Analysis of Consequences Following a DBLOCA with VP in Operation in Mode 3 Following the SGR outage.
Response - The following iodine removal efficiencies were used in the calculation:
Particulate 99%
Elemental 90%
Organic 70%
The discussion portion of the calculation has been revised to reflect the iodine removal efficiencies that were used.
Question 3 - The UFSAR discussion on operation of the Control Room Ventilation System (VC) is inconsistent on the discussion of control. room pressurization on page 15-113 and Table 15-34.
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Page 2 l
Response - Table 15-34 is correct in stating that VC pressurization with outside air is assumed to be 1800 CFM.
Section 15.6.5.3 will be revised in the next update.
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Question 4 - Provide assurance that the VP filters will be in place and operable prior to the initiation of containment purging in Modes 4 and 3.
Provide assurance that the VP Sys*em will remain intact following a postulated LOCA.
9 Response - Since credit is taken for the VP filters in the dose analysis discussed above, either train of the Containment Purge System that is utilized for purging lower containment in Modes 4 and 3 will have an operable filter package per the surveillance
. requirements of Technical Specification 4.9.4.2.
l Table 9-40 of the UFSAR discusses conformance to Regulatory Guide l
1.52, Rev.
1.
As noted in the comment to Regulatory Position C-2-d, the VP System is not subject to any containment pressure surges.
Containment isolation valves prevent the pressure surge from reaching the filter train.
Closure of the VP valves is discussed further in Attachment 3.
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4 MCC-1227.00-00-0048 a
Appendix B bM By:
Date:
ff
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Page z7o of Computer. Code: DOSESITE Calculation:
COM-0204.C6-11-0042
==
Description:==
DOSESITE is a certified FORTRAN code used to calculate doses from all postulated design basis i
accident (DBA) release paths from Containment to the environment.
Doses are calculated at the j
Exclusion Area Boundary (EAB) and Low Population j
Zone (LPZ).
For any DBA, there are three potential release pathways, listed below:-
it a.
Containment Leakage --> Through VE Filters
}
--> Either Exhaust to Environment or Recirc to Annulus, b.
Containment Leakage --> Bypass VE Filters -->
3 Exhaust to Environment, U
ECCS Recirc Leakage --> Through VA Filters c.
--> Exhaust to Environment.
s There are six activity removal mechanisms that are
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modeled in the code, including:
3 1.
Ice Condenser (Iodines),
2.
3.
4.
Auxiliary Building Filters (Iodines),
5.
Radioactive Decay (Iodines and Noble Gases),
6.
Containment Leakage (Iodines and Noble Gases).
j An iterative process is used to calculate the activities released to the EAB and LPZ.
Reg.
Guide 1.109 dose conversion methodologies are utilized to determine the dose values in the EAB and LPZ.
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A complete description and derivation of the DOSESITE computer code can'be found in the verification calculation file listed above.
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4 McGuire Nuclear Station Response to NRC Staff Questions Containment Purge in Modes 4 and 3 1.
Provide technical details about the containment purge valves and the valve operators, including type, size, model number, l
aspect ratio, and disk type.
Are these valves and operators identical in model and part number to the containment purge valves at Catawba? Provide technical details of the differences, if any.
Response
The valves and actuators to be used for purging at l
McGuire are identical to the valves used at Catawba (24" Fisher L
Type 9200 with Bettis 732C-SR60 actuator).
The NRC Staff has previously reviewed the closure adequacy review report performed by the valve vendor (Fisher Controls) as discussed in the Staff's SER attached to Amendment No. 150 for Catawba Unit 1 dated July l
30, 1996.
1 2.
Provide information that should be documented in the IST program for these valves.
If these valves are not in the IST program, provide justification.
Response
The VP valves are currently in the IST program for Tech Spec required leak rate test (Test Requirement #1, "LT-TS).
l However, the stroke time test requirement was removed per Unit 1 l
Rev 14/ Unit 2 Rev 10 (4/20/90) on the basis that they only have a containment integrity function in Modes 1-4 and they are not opened during these modes and are passive as far as stroke time
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is concerned.
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- 3. Will the remote position indicator verification and the fail 1
safe test be performed, as required by ASME Section XI, prior
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to purging operat ions in Modes 3 and 4?
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Response
Yes.
The following tests will be performed on the VP valves prior to entry into Mode 4: a Type C leak test, a remote position indication verification test, a fail safe test, a stroke time test and a spring torque output test.
1 4.
Please provide the calculations, data, and assumptions that are part of the flow test performed by the manufacturer referenced in Attachment 2 to the proposed Technical Specification amendment.
1 1
s' Page 2
Response
This information is the same as that provided for Catawba in Report FOR-49, Rev. A dated May 30, 1995, 24" Type i
9200 Containment Purge Isolation Valve Closure Adequacy Review.
The NRC Staff has previously reviewed this report as discussed in j
the Staff's SER attached to Amendment No. 150 for Catawba Unit 1 dated July 30, 1996.
- 5. ANSI B16.41, Appendix J, recommends extrapolation proportion limits of 50-200 percent of nominal piping diameter.
Were the valves used by the manufacturer to perform the flow test within these limits?
If not, please provide justification.
Response
Please see W.
R. McCollum, Jr.'s letter dated May 20, 1996, Response to RIA #3.
As noted above, the NRC Staff has previously reviewed the closure adequacy review report performed by the valve vendor (Fisher Controls) as discussed in the Staff's i
SER attached to Amendment No. 150 for Catawba Unit 1 dated July 30, 1996.
- 6. What are the required seating torques for the valves?
Are the actuators adequately sized for the required seating torque?
Response: Please see W.
R. McCollum, Jr.'s letter dated May 20, 1996, Response to RIA #4.
The valve torque requirements are also discussed in the Staff's SER attached to Amendment No. 150 for Catawba Unit 1 dated July 30, 1996.
- 7. Have the flow path characteristics such as elbows and tees been reviewed against assumptions in the analysis of torque and self closing performance under DBLOCA conditions?
Response
Review of Report FQR-49 does not indicate that flow path characteristics are a significant consideration in the expected closing response of the VP valves.
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