----- Forwarded by Jaime Pagan/RTP/USEPA/US on 12/08/2008 10:32 AM

-----

Robin Weeks <Robin.Weeks@kirbycorp .com>

12/05/2008 05:00 PM To Jaime Pagan/RTP/USEPA/US@EPA

cc Subj ect

Jaime, I understand the attached letter from the EMA has been s ent to your attention. As a supplier to the nuclear power industry of emergency diesel generators, we at Engine Systems, Inc. have an interest in this issue as well. I would like to state our support for an exemption for emergency and station blackout di esel generators for large engines as discussed in the letter, as well as for any size engine used in this critical application. For the reasons stated below, we believe that the public interest is better served by providing reliable emergency diesel power fo r nuclear applications.

Safety

- Related Components Emergency diesel generators (EDGs) are required by the US Nuclear Regulatory Commission to be qualified for safety related service. There are a number of existing standards such as IEEE 387, IEEE 344, IEEE 323, and USNRC Reg Guide 1.9 among others that state the requirements for diesel generator qualification and reliability. My company and the nuclear power industry spends a great deal of resources in qualifying diesels and diesel components for this demanding service, as well as maintaining them over the life of the nuclear power plant, typically 40 years in the past, but now being extended to 60 years. Nuclear power plants utilize commercial power sources to operate and control the reactor, reactor coolant pumps, and all of the normal power needs at the plant. Diesel engines have a long history of providing emergency backup power during loss of offsite power (LOOP) events. Items that provide the safety

- related function are defined as components tha t assure:

 The integrity of the reactor coolant pressure boundary

 The capability to shut down the reactor and maintain it in a safe shutdown condition; or

 The capability to prevent or mitigate the consequences of accidents which could

re sult in potential offsite exposures Note that the exposure being mentioned, is the public exposure to a radiation release from a nuclear power plant. Class 1E components are the electrical components and systems in a nuclear power plant that have a safety

- related function. Emergency diesel generators are classified as 1E components. IEEE 323 states: "Class 1E equipment in nuclear power generating stations must meet its safety functional requirements throughout its installed life. This is accomplished by a thorough program of quality assurance, design, qualification, production, transportation, storage, installation, maintenance, periodic testing, and surveillance."

Diesel Engine Operation The above requirements, particularly with respect to testing and s urveillance has meant in the past that nuclear power operators start their diesel generators monthly, operate them for a 1

- 2 hours, and then keep them in a standby mode until the next monthly surveillance run is initiated.Every refueling outage which is either on an 18 or 24 month cycle, the operators typically run

their diesel for 24 hours. Over the course of an entire year, these units may have fewer than 50 running hours accumulated. They have so few hours in fact, that the scheduled maintenance of th ese diesels is based on calendar time, not running hours as it typical of commercially operated units. It is an open question as to whether or not diesel exhaust aftertreatment equipment can be successfully qualified for 1E safety

- related service. One of the critical issues for qualification is that the safety

- related component must be functional both during and after a design basis seismic event. If the component fails during a seismic event such that the diesel engine cannot operate, then the diesel gen erator has failed to meet it safety

- related function. In addition, if the exhaust aftertreatment were to require maintenance during operation of the diesel generator in an emergency, due to a failure of one of its systems or components, or due to a more ro utine service issue, then it could also prevent the diesel generator from performing its safety

- related function, thus placing the public at risk. In addition, emergency diesel generators are typically required to start and be ready to load (operating at rated voltage and frequency) in 10

- 15 seconds. Typical exhaust aftertreatment systems are not functional during such a rapid startup, and would therefore be ineffective. It may also be the case that the diesel is started but left unloaded during a loss of coolant incident (LOCA), wherein the normal commercial power supply remains available. In this case the exhaust temperature of the diesel engine may be too low for the exhaust aftertreatment equipment to function properly. Wh ile a solution may be to provide an auxiliary burner in the exhaust system to artificially elevate temperatures, this is a poor use of the limited volume of onsite stored diesel fuel which is devoted to the emergency needs of the diesel genset. Again, this could potentially put the public at risk if the LOCA were followed by LOOP.

Webelieve it is not in the best interest of public safety for an emergency diesel generator which operates so few hours per year to be burdened with the additional exhaust aftertreatment systems require d by 40CFR60. There is little to no environmental benefit, but there exists a potential risk to the public that the emergency diesel will be unavailable to the operate when required. A requirement for exhaust system aftertreatment makes a great deal of se nse for protecting the environment in commercial applications such as baseload power production, or peaking service. These are operations where the diesel engine would either be operating around the clock for baseload applications, or for 6

- 8 hours or more each day in peaking service. This is not the case with backup emergency power at nuclear stations. Since emergency diesel engines operate rarely except for once per month surveillance testing, they have an insignificant impact to the environment. Nevertheless the complexity, added cost, physical size, and ongoing maintenance activities that would be associated with exhaust af tertreatment systems for these engines is apparently being ignored in favor of regulating diesel engines broadly regardless of app lication. More importantly, reliability may be adversely affected which is directly related to public safety in the event of an accident. Webelieve that the risks associated with a potential release of radiation to the public far exceed any benefit deriv ed from exhaust aftertreatment systems for emergency diesel generators. Much like the fire pump engine case, where the benefits of a reliable diesel engine far exceed any short term increased diesel emissions during the course of operating during this cri tical mission, we believe the public interest is to ensure the proven reliability of emergency diesel generators is maintained. Weurge the EPA to p rovide the exemptions requested in the EMA letter. W e also encourage this exemption to be extended to all emergency diesel generators and station blackout diesel generators provided to nuclear power plants, regardless of cylinder displacement.Thank you,

Robin L W eek s Applications Engineer Engine Systems, Inc. (252) 407

- 8517

fax (252) 446

- 1134