Pilgrim Heater: "I'll gladly pay you Tuesday for a hamburger today".

Popeye’s J. Wellington Wimpy "I'll gladly pay you Tuesday for a hamburger today".

Why pay the price of a plant shutdown...a proper refueling outage when you can put off maintenance today for maintenance in the distant future.

This condition resulted in the development of a susceptible condition resulting in a failure by shell leakage of the heater during operation on August 15, 2014.

Come on, if the NRC and Entergy were competent, they would have replaced this heater in the prior refueling outage. What they all proved to us is they have zero capability to predict a heater failure and its erosion.

Dates: April 1, 2015 through June 30, 2015

August 11, 2015

SUBJECT: PILGRIM NUCLEAR POWER STATION - INTEGRATED INSPECTION

REPORT 05000293/2015002

Annual Sample: Through-wall Leak of Feedwater Heater Shell E-103B

a.    Inspection Scope

b.     

The inspectors performed a review of Entergy’s root cause evaluation and corrective actions associated with CR-2014-4052. The inspectors assessed the problem identification threshold, extent of condition reviews, and the prioritization and timeliness of corrective actions to determine whether Entergy personnel were appropriately identifying, characterizing, and correcting problems associated with the history of the erosion/corrosion of numerous locations of the E-103B feedwater heater shell.

Specifically, feedwater heater E-103B has a history of shell erosion/corrosion issues. Since 1999, these issues have been resolved by a series of repairs and evaluations performed as needed to extend the replacement date of the heater. The Flow Accelerated Corrosion Program has measured and monitored the thickness of portions of the shell since 1999. No tubes have been plugged (removed from service) since heater installation in 1984. Feedwater heater E-103B was removed and replaced during the current refuel outage (RFO 20) with an identical heater procured without modification or change to original specifications. The replacement feedwater heater was procured for a planned replacement due to the continued degradation and resultant leaks in the shell.

The inspectors assessed Entergy’s problem identification threshold, cause analyses, extent of condition reviews, compensatory actions, and the prioritization and timeliness of Entergy’s corrective actions to determine whether Entergy staff were appropriately, identifying, characterizing, and correcting problems associated with this issue and, whether the planned and/or completed corrective actions were appropriate. The inspectors took note that the feedwater heater while being risk significant is not a safety-related component. However, the feedwater heater was designed and fabricated to the requirements of ASME Section VIII. In addition, the inspectors interviewed responsible engineering personnel to assess the effectiveness of the implemented corrective actions.

b. Findings and Observations

No findings were identified.

The direct cause of the shell leaks was erosion of shell base metal and penetration in areas around the shell structural stiffeners until those areas could no longer carry the required loads. The inspectors reviewed test records of ultrasonic thickness readings acquired to support that wall thickness met the acceptance levels contained in engineering documents. However, wall thinning and loss of adjacent structural support to the shell and stiffeners continued.

The inspectors reviewed Entergy’s causal evaluation that identified the likely causes of the failure, including the degradation by corrosion of the shell in numerous area locations and in the areas of shell structural support. This condition resulted in the development of a susceptible condition resulting in a failure by shell leakage of the heater during operation on August 15, 2014. The inspectors noted that a replacement for the E-103B heater had been purchased and placed into storage in 2000.

The inspectors confirmed the critical parameters were being tracked and included appropriate alert and action levels when wall thinning decreased to a “t-critical” level. This wall thickness provides design margin with an inclusive allowance such that action is taken prior to actual encroachment on the design minimum allowable wall thickness.

The inspectors also reviewed a selection of sample locations where the highest wear rates have been detected in heater wall thickness monitoring plans. The inspectors interviewed engineering staff and reviewed test data to verify that monitoring and trending of wear data was measured and evaluated by engineering personnel.

The inspectors reviewed a selection of test data for various components and did not identify any additional issues. The inspectors determined Entergy’s overall response to this issue was commensurate with the safety significance, was timely, and included reasonable compensatory actions. The inspectors concluded that actions completed were reasonable to correct the problem and prevent reoccurrence.