ML20199K652
| ML20199K652 | |
| Person / Time | |
|---|---|
| Site: | Mcguire |
| Issue date: | 11/21/1997 |
| From: | Barron H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9712010174 | |
| Download: ML20199K652 (4) | |
Text
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Mdisi,r Nudrar Station
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- MG01VI' 12700 Ilagers l'erry Rd.
lluntersville, NC 28078-9M0 H. B. Barrom We hesident. MsGui,e (704) 873 4800 cvnct Nudeer Generation ikpartmens (704) 875-4809IAx November 21, 1997 U.
S. Nuclear Regulatory Commission Doct: ment Control Desk Washington, D. C.
20555
Subject:
McGuire Nuclear Station, Unit 2 Docket No. 50-370 Containment Purge in Modes 3 and 4
References:
- 1) Duke letter of January 26, 1996 from W. R. McCollum, Jr. to the Document Control Desk
- 2) Duke letter of May 6, 1996 from W.
R. McCollum, Jr. to the Document Control Desk
- 3) NRC letter of July 30, 1996 issuing Amendment 150 to Catawba Unit 1 FOL
- 4) Duke letter of January 6, 1997 from M.
S.
Tuckman to the Document Control Desk
- 5) NRC letter of April 24, 1997 issuing Ame#Unent 174/156 to McGuire Units 1 and 2 FOLs As detailed in Reference 5,
the NRC approved a
one-time revision to Technical Specifications 3.6.1.1, 3.6.1.2, 3.6.1.8, and 3. 6.1. 9 for McGuire Units 1 and 2.
This change allowed operation of the Containment Purge Ventilation System in Modes 3
and 4
during startup from each unit's steam generator replacement outage.
This change was deemed necessary due to respiratory hazardous gases which would jeopardize personnel safety.
The Steam Generator (S/G) Replacement outages at Catawba Unit 1 and McGuire Unit 1 were completed in late 1996 and early 1997, respectively.
As expected, purging of lower containment f
during heatup prior to critical operation of each unit following. S/G replacement has proven to be an ef fective - and safe means of eliminating respiratory hazardous gases from lower containment and providing a safe work environment for workers who must complete necessary tasks in lower containment
/
prior to unit startup.
8 Ad/h 971201017497gt P"
eof IllIlElEJI(5lIlM
U. S. Nuclear Regulatory Commission
-No,vember 21, 1997 Page 2 One of the assumptions in the dose analysis in support of the Amendments for Catawba Unit 1 and McGuire Units 1 and 2 was the period of time that the core had decayed prior to a postulated accident during purging operations.
For Catawba Unit 1, 80 days had been assumed. For the McGuire Units 1 and 2 analysis, this was shortened to 70 days.
As a result of schedule improvements, McGuire Unit 2 may be ready to re-enter Mode 4 in less than 70 days The analysis previously provided in Reference 4
has been revised to assume 65 dsys of core decay verces the previous assumption of 70 dnys.
All other assumptions in the analysis remain unchangede The revised doses are presented in Attacnment 1.
L In response to a previous NRC Staff question, a commitment was made for Catawba (Reference 2) to provide eye protection to Control Rocm personnel in the unlikely event of significant Reactor Coolant System leakage, failure of a Containment Purge isolatien valve and detection of beta activity or noble gases in the Control Room.
With this commitment, the NRC used a 7S Rem Control Room Operator skin dose acceptance limit for Catawba.
The eye protection committnent was included in Reference 4 for McGuire Units 1 and 2. For McGuire Units 1 and 2,
the Staff's SER (Reference b) used ar2 acceptance limit of 30 Rem fcr Control Room Operator Skin dose.
The calculated result presented was 30 Rem leaving no margin to the stated acceptance limit.
The revised doses presented in Attachment 1 are below the stated 6cceptance limits.
For skin doce this is based on a 75 Rem acceptance limit.
McGuire is changing its commitment regarding days of decay prior to VP operation to 65 days from the original 70 day commitment.
If additional information is required, please call Robert Sharpe at (704) 382-0956 or Mike Cash (704) 875-4117.
Very truly yours, Yk/
H.
B.
Barron
I rs s
l U.
S. Nuclear Regulatory Commission November 21, 1997 Page 3 cc:
Mr. V. Nerses, Project Manager Office of Nuclear Reactor Regulation U.
S. Nuclear Regulatory Commission Mail Stop 14H25, OWFN Washington, D.
C.
20555 Mr.
L.
A.
Reyes, Regional Administrator U.
S.
Nuclear Regulatory Commission - Region II 101 Marietta Street, NW - Suite 2900 Atlanta, Georgia 30323 Mr.
S.
M.
Shaeffer Genior Resident Inspector I*cGuire Nuclear Station Mr. Dayne Brown, Director Division of Radiation Protection P.
O. Box 27678 Raleigh, North Carolina 27611-7687
d 3
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1
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McGuire Nuclear Station Unit 2 I
Revised Dose Analysis in Support of Containment Purging Following S/G Replacement I
The following is the results of dose analyses performed by Duke to determine the upper f
bounds to the doses to the Exclusion Area Boundary (EAB), the Low Population Zone (LPZ),
and the Control Room for the sequence described in Reference 4.
j 4
70 Days Core Decay 65 Days Core Docr.y Gaideline Values (10 CFR 100)
Doses to the EAB Doses to the EAB j
Whole Body Dose:
0.0692 Rem Whole Body Dose:
Thyroid Dose:
88.3 Rem Thyroid Dose:
206 Rem 300 Rem Doses to the LPZ Doses to the LPZ i
j Whole Body Dose:
0.0219 Rem Whole Body Dose:
0.0181 Rem 25 Rem Thyroid Dose:
18.5 Rem Thyroid Dose:
Guideline Values
[
Doses to the control Room Doses to the Control Room (GDC 19, SRP 6.4) l Whole Body Dose:
0.012 Rem Whole Body Dose:
Skin Dose 5.39 Rem Skin Dose 5.91 Rem 75 Rem
- Thyroid Dose:
5.61 Rem Thyroid Dose:
i i
- Applicable with eye protection 4
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