ML20058J061

Provides Current Status & Schedule for Completion of Remaining Actions Re Util Response to NRC Bulletin 88-011, Pressurizer Surge Line Thermal Stratification

ML20058J061
Person / Time
Site:	Davis Besse
Issue date:	12/03/1993
From:	Storz J CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2190, NUDOCS 9312130361
Download: ML20058J061 (3)

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300 Mod: son kenue Louis F. Storz Toledo. OH 43C52-0001 Vice Pres: dent-Nuclear 4G-24973OO Davis Besse Docket Number 50-346 i

License Number NPF-3 j Serial Number 2190 December 3, 1993 United States Nuclear Regulatory Commission  ;

Document Control Desk Washington, D. C. 20555 Subj ec t : Status of Remaining Actions Relating to Toledo Edison's Response to NRC Bulletin Number 88-11, Pressurizer Surge Line ,

Thermal Stratification, for the Davis-Besse Nuclear Power y Station ,

i Gentlemen:

The purpose of this letter is to provide the current status and Toledo ,

Edison's schedule for completion of the remaining actions relating to Toledo Edison's response to NRC Bulletin Number 88-11, Pressurizer Surge Line Thermal Stratification, for the Davis-Besse Nuclear Power Station (DBNPS). Toledo Edison's letter dated October 8, 1991 (Serial Number 1982) identified the remaining actions to resolve Bulletin 88-11 for the DBNPS. j The October 8, 1991, letter included BAV-2127, Supplement 1, ,

" Plant-Specific Analysis in Response to NRC Bulletin 88-11, Pressurizer-Surge Line Thermal Stratification," which provides the plant-specific '

analysis for the DBNPS. The report shows that stresses for.the surge line pressure boundary components remain within allevable limits and [

that accumulated fatigue-usage vill satisfy the applicable code l requirements and regulatory commitments for the 40 year licensed life ,

of the DBNPS. This report was predicated on the assumption that certain modifications to pressurizer surge line whip restraints and a spring support and upgrading of insulation vould be completed during Seventh Refueling Outage (7RFO). For the reasons described in Toledo '(i.:

Edison's October 8, 1991,-(Serial Number 1982) these modifications vere ~ '

not accomplished in the 7RFO as originally planned. Serial Number 1982 .l provided justification that continued operation is acceptable at least  ;

through the Ninth Refueling Outage (9RFO) by which time all remaining  ;

act'ans related to Bulletin 88-11 would be completed. The Ninth i Refueling Outage is currently scheduled to commence on October 1, 1994.

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Docket Number 50-346 License Number NPF-3  ;

Serial Number 2190 Page 2 The remaining actions include updating BAV-2127, Supplement 1, to reflect the effects of two additional plant operating cycles on the pressurizer surge line fatigue evaluation for the full 40 year licensed life of the DBNPS. Additionally, as indicated by Serial Number 1982,  :'

the update of BAV-2127, Supplement 1, vill incorporate the NRC approved methodology for determining fatigue usage of the surge line elbows ,

which was recently approved by the NRC in a letter to the Babcock and >

Vilcox Owners Group (BV0G) dated September 16, 1993. Analysis to update BAV-2127, Supplement 1, is ongoing. Toledo Edison expects to ,

submit the update of BAV-2127, Supplement 1, in March 1994.

Toledo Edison's letter dated October 8, 1991, identified several other [

actions for long term resolution of the issues identified in NRC Bulletin 88-11. The following summarizes the status of each of the r identified items:

1. Procedures will be modified to ensure operation within the bounds of pressure-temperature limits during heatup and cooldown as described in Section 8 of BAV-2127, Supplement 1.

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Status: Completed. .

2. The cycling of the makeup flow will be reviewed to ensure that any  ?

related fatigue effects due to thermal striping in the surge line vill not significantly affect surge line reliability. In the event  ;

that plant modifications are required, they are planned to be ,

completed before heatup from the Ninth Refueling Outage.

Status: Completed. Cycling of makeup flow has been evaluated and determined to have an insi, . " cant effect on the pressurizer surge line.

3. Modifications vill be completed ensuring that the surge line whip  !

restraints and spring support PSU-H1 do not interfere with piping [

thermal displacement. Also, the anchor bolts on the support i structure for PSU-B1 vill be restored to a safety factor of four.

Status: These modifications are scheduled for completion during the 9RFO.

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4. Consistent with modifications to the surge line vhip restraints,  ;

the surge line thermal insulation performance vill be upgraded by suitable modifications. The improvement in.the insulation vill result in reduced top-to-bottom temperature differences, more.

nearly resembling those observed at Oconee Unit 1. 1 Status: These modifications are scheduled for completion during the 9RFO.

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Docket Number 50-346 ,

- License Number NPF-3 l

. Se, rial Number 2190 +

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5. During the heatup following completion of the insulation improvements, the surge line thermal conditions vill be monitored  ;

to confirm the conservatism of the analysis for future surge line  !

conditions.

Status: This is scheduled for completion during the 9RF0.

6. The number of heatups and cooldowns vill be monitored to ensure that 50 heatup/cooldown cycles are not. exceeded prior to heatup from the Ninth Refueling Outage.  ;

Status: Ongoing.

Should you have any questions or require additional information, please

• contact Mr. Villiam T. O'Connor, Manager - Regulatory Affairs, at (419) 249-2366.

Very truly yours, ,

ac, PVS/amb ,

cc: J. N. Hannon, NRC/NRR Project Director PD-III-3 J. B. Hopkins, NRC Senior Project Manager J. B. Martin, Regional Administrator, NRC Region III ,

S. Stasek, DB-1 NRC Senior Resident Inspector  !'

Utility Radiological Safety Board ,

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