ULNRC-04939, Response to 11/12/03 Meeting Questions Regarding Application of Proprietary Leak-Before-Break (LBB) Methodology Reports and Draft Regulatory Guide DG-1108

Response to 11/12/03 Meeting Questions Regarding Application of Proprietary Leak-Before-Break (LBB) Methodology Reports and Draft Regulatory Guide DG-1108

ML040270055
Person / Time
Site:	Callaway
Issue date:	01/14/2004
From:	Keith Young AmerenUE
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
DG-1108, ULNRC-04939
Download: ML040270055 (5)

Text

Union Electic One Ameren Plaza I"

1901 Chouteau Avenue PO Box 66149 St. Louis, MO 63166-6149 314.6212m2 January 14,2004 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 Ladies and Gentlemen: ULNRC- 04939 t7§1 wAmeren UE DOCKET NUMBER 50483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

FACILITY OPERATING LICENSE NPF-30 APPLICATION OF PROPRIETARY LEAK-BEFORE-BREAK (LBB) METHODOLOGY REPORTS AND DRAFT REGULATORY GUIDE DG-1108

References:

1. ULNRC-04868 dated June 27, 2003

2. ULNRC-04926 dated December 9, 2003 In Reference 1 above, AmerenUE transmitted an application for amendment to Facility Operating License No. NPF-30 for the Callaway Plant. During the NRC review of that amendment application, several questions arose which were discussed during a meeting with NRC staff on November 12, 2003. Reference 2 above provided the responses to those questions.

During a teleconference on December 19, 2003, additional issues were discussed on the response to the shielding question (pages 12-14 of Attachment 1 to Reference 2). The first issue involved a verification that this shielding modification would not impact vital area access to the plant during the course of an accident (NUREG-0737 Action Item II.B.2). The second issue requested that AmerenUE provide a more quantitative basis (i.e., dose saved outweighs any additional dose resulting from the modification) supporting our statements that this modification is an ALARA measure. The following discussion addresses the two additional issues.

C0oD asubsidIary .1fAmetn Corporfadn

ULNRC-04939 January 14,2004 Page 2 We have reviewed the equipment located within the zone of influence on the 2000 foot and 2026 foot elevations of the Reactor Building and found no equipment that would require possible personnel interface. If plant personnel happened to be inside containment during power operations, they would be just passing through the area and would not exceed the dose currently received during a refueling outage.

Since the secondary bio-shield walls are not fission product barriers, they were not designed to provide shielding to meet design basis event dose rates. As such, vital area access will not be affected. In addition, we looked at the dose rates that might be affected outside of the Reactor Building as a result of cutting this access door through the bio-shield wall. Our investigation showed that no credit is taken for our secondary bio-shield wall for dose calculations outside of containment; therefore, cutting this doorway will not change that design basis.

The purpose of cutting a doorway through the 'C' loop SG secondary bio-shield wall is to provide a safer, faster way of accessing the secondary steam generator platforms and the reactor coolant pumps. A review of outage work history and dose rates at Callaway Plant indicates that, during a normal refueling, outage scaffold crews will receive about 80 mrem installing access scaffold ladders to the secondary platform (sludge lance platform). The temporary ladders are needed because normal access is closed off due to steam generator maintenance activities.

The ladders are dangerous from a personnel safety aspect because they are approximately 25 feet high with no cage, therefore fall protection is required. We looked at the time it took to access the temporary ladder, climb it, and raise tools to the platform and multiplied this time by the dose rates in the area and the number of entries during a refueling outage. We conservatively estimated the dose received during a refueling outage just for this activity to be approximately 500 mrem. If one compares the dose of 580 mrem/refueling outage to the increased dose rates personnel may be exposed to outside the bio-shield wall as a result of cutting the access doorway, one can calculate stay times for an equivalent dose. Based on this, we concluded that personnel would have to be within the zone of influence on the 2000 foot elevation of the Reactor Building, which will have a dose rate of 188 mremlhour, a total of 3.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> during a cycle. Likewise, personnel would have to be within the zone of influence on the 2026 foot elevation of the Reactor Building, which will have a dose rate of 67 mrem/hour, a total of 8.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> during a cycle.

Based on the above, total exposure to plant personnel will be reduced as a result of providing an access doorway through the secondary bio-shield wall at this location resulting in keeping personnel exposure ALARA. In addition, we will be eliminating the personnel safety concern of climbing the temporary ladder to the sludge lance platform.

ULNRC-04939 January 14, 2004 Page 3 If you have any fiuther questions on this amendment application, please contact us.

Very truly yours, Keith D. Young Manager, Regulatory Affairs KDY/TEH/WMC/GGY/mlo

STATE OF MISSOURI )

) SS COUNTY OF CALLAWAY)

Keith D. Young, of lawfil age, being first duly sworn upon oath says that he is Manager, Regulatory Affairs, for Union Electric Company; that he has read the foregoing document and knows the content thereof; that he has executed the same for and on behalf of said company with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.

By 00, Ke~tD. Young IU Manager, ReguVaory Affairs SUBSCRIBED and sworn to before me this i dayNof Plan r , 2004.

8 NOTA&' '- imUtA PLCbI NOTAX OMN PUBLIC eQ-a" ItCo

ULNRC-04939 January 14, 2004 Page 4 cc: U.S. Nuclear Regulatory Commission (Original and 1 copy)

Attn: Document Control Desk Mail Stop P 1-137 Washington, DC 20555-0001 Mr. Bruce S. Mallett Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)

Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 7E1 Washington, DC 20555-2738 Manager, Electric Department Missouri Public Service Commission PO Box 360 Jefferson City, MO 65102