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December 20, 2006

* Overly conservative NRC regulation: Seismic calculations for piping system design

October 22, 2004

* Browns Ferry - pipes carrying > 200¡F fluids will be 316 SS NG material, not susceptible to IGSCC

September 3, 2004

* Grand Gulf - evaluation of effect of degraded pipe supports

November 7, 2003

Pilgrim requests relief from pressure test requirements for some small pipes in high rad area

Instead of hydrostatic testing, Pilgrim has proposed to substitute visual examinations of Reactor Coolant Pressure Boundary (RCPB) vent, drain and branch (VTDB) lines and connections for evidence of leakage every outage, and to check them during the 10-year ISI pressure test after four hours at pressure associated with 100% power. All the examinations would be conducted with the isolation valves in their normally-closed position. Plant Hatch was granted similar request in 1998. The proposed alternative will allow plant personnel to avoid an estimated one person-rem per outage, as the valve alignment and realignment required for the hydrostatic test would have to be performed in high radiation area near main steam loop piping within containment. The request also notes that, since the hydrostatic test would have to be performed after all RCPB maintenance is complete, it would always tend to occur at the end of an outage, and thus the time required to set up, test, and restore would impact outage schedule -- an unnecessary hardship pursuant to 10 CFR 50.55a(a)(3)(ii) without a sufficient compensating increases in the level of quality and safety. Entergy requests approval by December 1, 2004, to allow implementation during refueling outage 15.

[Source: William J. Riggs (Pilgrim Station - Director, Nuclear Assessment), letter to NRC, "Pilgrim Relief Request (PRR)-29, Relief from System Hydrostatic Test Requirements for Small Bore (² 1-inch), ASME Code Class 1 Reactor Coolant Pressure Boundary (RCPB) Vent, Drain and Branch (VTDB) Lines and Connections", November 7, 2003] Note: a PDF copy of the letter and Relief Request No. 29 is available from NRC at: http://www.nrc.gov/reading-rm/adams/web-based.html, by entering accession number ML033240525

July 1, 2003

* Pipe inspection - relative advantages and weaknesses of radiography vs ultrasonic, two complementary techniques

May 28, 2003

* Piping - progress in 'Cyclic Thermal Fatigue' modeling aids in proactive management of this piping failure mechanism

May 15, 2003

NEI thinks NRC staff exaggerates industry characterization of pipe failure experience

NRC staff draft: "The Nuclear Energy Institute (NEI) position states that pipe whip, jet impingement, spray or flooding from non-safety-related (NSR) systems could create additional failures of safety-related (SR) SSCs. The staff believes that this sentence should be revised as follow: 'Physical impacts, such as pipe contact (pipe falling such that it physically contacts safety-related equipment), pipe whip, jet impingement, spray or flooding, etc. from NSR SSCs could create additional failures of SR SSCs. This revision specifically identifies the need to consider the potential for structures and components (SCs) falling onto SR SCs and is consistent with industry operating experience with identified failures.

NEI Response: "Operating experience suggests that only high-energy FAC failures need to be addressed. The definition of high energy should be in accordance with the plant licensing basis."

[Ref: NEI handout at May 15, 2003 meeting with NRC, titled "Responses To Staff Comments On Industry Guidance On 54.4(A)(2) Scoping Criterion", released by NRC via ADAMS on June 17, 2003 as ACN ML031620032]

April 21, 2003