ML20094J974
| ML20094J974 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/08/1992 |
| From: | Broughton T GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| C311-92-2035, NUDOCS 9203170194 | |
| Download: ML20094J974 (2) | |
Text
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houfe 441 South Middletown, Pennsylvania 17057 0191 711 944 7621 TEL.EX 64 2386 Writer's Direct Dial Nurnber:
(717) 948-8005 March 8, 1992 C311-92-2035 U.S. Nuclear nagulatory Commission Attn: Docume "ontrol Desk Washington,., 20555
Dear Sir:
Subject:
Three Mi k Island Nuclear Station, Unit 1 (THI-1)
Operating License No. DPR-50 Docket No. 50-289 Request for Approval to Use ASME Code Case N-498
" Alternative Rules for 10-Year Hydrostatic Pressure Testing for Class 1 and 2 Systems,Section XI, Division 1" Pursuant to 10 CFR 50.55a(g)(5)(iii), GPU Nuclear requests approval to implement the alternative rules of ASME Section XI Code Case N-498 for Class 1 and 2 systems which was approved by the ASME on May 13, 1991.
The currently applicable Edition of the ASME Code Section XI for THI-l is the 1986 Edition.
Code Case N-498 allows a VT-2 visual leakage examination to be performed at nominal operating pressure rather than at the Code required hydrostatic test pressure. The provisions of Code Case N-498 would be used in lieu of the 10-year hydrostatic pressure tests required by ASME Section XI Table IW8-2500-1. Category B-P, and Table IWC-2500-1. Category C-H.
It is understcad that Code Case N-498 has been reviewed by the NRC and found acceptable although approval has not been reflected in Regulatory Guide 1.147.
It is also understood that approval for use has been granted to other licensees, e.g.,
,gg Cooper, Salem-1, and WPPS-2.
000.
gg Use of the alternative rules will reduce cost, critical
)ath outage time, and em total radiation exposure to personnel without reducing tie level of cuality or "O
safety.
Leakage would not be appreciably more apparent using the hycrostatic y
test as compared with the VT-2 visual examination allowed by Code Case N-498
-< o because the applicable system hydrostatic test pressure would not apply RQ significant additional stress to the piping.
It is noteworthy that IMI-l has completed thirteen (13) system hydrostatic tests to date and never found weld gg or piping throughwall leakage.
& a. n-t Personnel exposure dose savings would be associated with elimination of the
/
need to install and remove hydrostatic test equipment, remove and blank relief I
I ' U GPU Nuclear Cotporabon is a subs:dtay of General Pubhc Ubkhes Corporation I
.s
Do'cument Control Desk C311-92-2035-Page 2 of ?-
valves, 2nd isolate and restore valve lineups reouired for the hydrostatic tests.
System hydrostatic tests that would be affected are:
i 1
Tir ' team System from the Once Through Steam Generator secondary side to:
an Steam Isolation Valves, the Emergency Feedwater Co drol Valvcs
' C/D), and the Main feedwater Check Valves (FW-Vl?A/B);
System; i
4 orn Injection System; R
in-
'lls and piping inside containment of Reactor Building Emergency Ceu t
.js em; 2.
Building Spray Sy', tem; 6.
3 4ecombiner System; 7.
Hipa i.
.ure Injection System; 8.
3t.ent t.-I Couling System; and 9.
Various Keactor Guilding penetrations, c
i;w first system to which this Code Case would be applied is the Main Steam System. A Hydrostatic test of the Main Steam System requires gagging or blanking of the eighteen (18) Main Steam Safety Valves (MSSVs) to achieve the required hydrostatic test pressure.
Gagging could potentially damage the MSSVs and would require a valve retest.for operability.
Blanking off the MSSVs would likely result in a need to retest some or all of the valves. An estimated four days of critical path time would be raved during an outage by using the alternative rules c' tede Cese N-498 rather than-performing a hydrostatic test of the Main Steam bysten er required by the currently applicable 1986 Code Edition.
in conclusic,,, tr.ere does not 1?. ear to be sufficient benefit to be gained to warrant the risks and resource tapact associated with system hydrostatic tests.
Approval is requested by May,1992 to facilitate the budgeting _and i.heduling of activities for the TMI-l Cycle 10 Outage (10R) which is scheduled to begin in Septamber, 1993.
Sincerely, V<A T. G. Bro hton Vice Pres dent and Director, TM:- 1 MRK cc: Region I Administrator lhi-1 Senior Project Manager TMI Senim Resident Inspector
.