EPA-HQ-OAR-2008-0708-DRAFT-0362 ----- Forwarded by Melanie King/RTP/USEPA/US on 02/17/2010 03:31 PM

----- |------------> | From: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |"Crockett, Steven" <Steven.Crockett@nrc.gov> |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | To: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |"Higgins, Cortney" <Cortney_Higgins@omb.eop.gov>, RobertJ Wayland/RTP/USEPA/US@EPA, Melanie King/RTP/USEPA/US@EPA, Michael | |Horowitz/DC/USEPA/US@EPA |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Cc: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |"Grahame, Thomas" <Thomas.Grahame@HQ.DOE.GOV>, "Wolfgang, Robert" <Robert.Wolfgang@nrc.gov>, "Lombard, Mark" <Mark.Lombard@nrc.gov>, | |"Imboden, Andy" <Andy.Imboden@nrc.gov>, "Droggitis, Spiros" <Spiros.Droggitis@nrc.gov> |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Date: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |02/05/2010 01:25 PM |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Subject: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |NRC standards on maintenance and testing |

>--------------------------------------------------------------------------- ---------------------------------------------------------------|

Page 1EPA-HQ-OAR-2008-0708-DRAFT-0362

You've asked for some description of the NRC's maintenance and testing standards on emergency diesels that fall within its jurisdiction. Below, I briefly describe the program and provide links to the key documents. There may be a further comment later today, or perhaps further documentation, but I hope that what's below contains the core of our response. At least it will move the discussion along.

Let me first make a general comment about our stance towards EPA's draft final rule. As we did in the case of EPA's Spill Prevention, Control, and Countermeasures rule, we're taking no position on whether the rule should apply to the diesels in the NRC's jurisdiction -- and EPA tells us that's not really an open question anyway. We're not fans of having two regulators overseeing the same machine for different purposes, but we recognize EPA's Clean Air Act jurisdiction here, and this is not a case like the cases involvling radionuclide emissions, where we and EPA were seeking to regulate the same thing for the same purpose (e.g., Yucca Mountain, decommissioning, radionuclide emissions to air). We're aiming mainly at providing information about our program, and at understanding, as best we can in the short time allotted, whether there's anything in the rule's approach to maintenance and testing that might raise a nuclear safety concern. These diesels are critical to ensuring safety in emergency conditions; so of course the maintence and testing of these diesels is critically important to us. And that's so whether we're talking existing diesels or new ones; the fact that the rule imposes no retrofits on existing emergency diesels doesn't eliminate the possibility that the rule might raise a nuclear safety concern.

However, to the extent that we understand this complicated rule -- necessarily complicated because of its great scope -- we don't think it raises a nuclear safety issue, at least not as a general matter, though details matter (and we note one below). Our principal standard on maintenance, 10 CFR 50.65, is a "performance-based" rule, and so leaves scope for variation in maintenance practices. Annually changing the very large quantity of oil in a huge diesel engine designed to provide emergency power to an operating nuclear power reactor is no light matter, but, in and of itself, it needn't pose an unacceptable risk. Similarly, we have testing guidance (listed below), but EPA's rule appears to leave room for its application.

What can matter though are detailed prescriptions. The reliability of EDGs can be one of the main factors affecting the risk of core damage from a station blackout. Changes of any kind in a safety-related system or component – including imposition of prescriptive maintenance procedures or maintenance schedules – could impact the prevention or mitigation of the consequences of accidents at nuclear reactors, because changes to the established maintenance procedures for an emergency diesel could impact its reliability or availability. Excessive maintenance could negatively impact the availability of the system or component, and excessive testing could negatively impact its reliability. For these reasons, we're concerned about one aspect of EPA’s prescriptive schedule for performing management practice requirements: EPA appears to allow delays in maintenance only when the diesel is operating in response to an ongoing emergency. See page 163, footnote 4. The NRC’s approach, on the other hand, is designed to minimize overall risk. 10 CFR 50.65(a)(4) states, “before performing maintenance activities ... the licensee shall assess and manage the increase in risk that may result from the Page 2EPA-HQ-OAR-2008-0708-DRAFT-0362 proposed maintenance activities.” This applies to emergency diesels, with the result that the NRC rule might allow a delay in maintenance when the EPA rule

would not. Could the footnote be expanded somehow to incorporate a judgment about overall risk? Could it say, for example, the following? "If an emergency engine is operating during an emergency and it is not possible to shut down the engine in order to perform the management practice requirements on the schedule required in the final rule, or if shutting the engine down would otherwise pose an unacceptable risk under federal, state, or local law, the management practice can be delayed until the emergency is over. The management practice should be performed as soon as practicable after the emergency has ended, or the unacceptable risk has abated."

We're less concerned about the rule's testing requirements, even though we've taken great care in the area of testing (see below), in order to avoid the extremes of too much testing (and therefore unnecessary wear and tear), or too little (and therefore inadequate demonstration of reliability). We're less concerned about the rule's requirements here, because they appear to leave room for the appropriate application of other federal, state, or local standards (see pages 148-49), and that would include the NRC's important guidance on the subject.

I hope that, in the future, when EPA is engaged in rulemaking that might apply to the NRC's licensee, the two agencies will be able to consult earlier than they were able to this time. Earlier consultation proved useful in the cases of EPA rulemaking on water intake structures and underground diesel fuel tanks. We keep an eye out for EPA rulemakings, but we sometimes miss them. I hope that the little consultation we've had these past few days has been useful to both agencies, and I hope too that we'll continue the consultation if unexpected issues should arise in the course of implementing the rule.

NRC DOCUMENTS ON MAINTENANCE AND TESTING OF EMERGENCY DIESEL GENERATORS AT

NUCLEAR POWER PLANTS.

- 10 CFR 50.63, Loss of all alternating current power.

- 10 CFR 50.65, Requirements for monitoring the effectiveness of maintenance at nuclear power plants.

- Regulatory Guide 1.160, “Monitoring the Effectiveness of Maintenance at Nuclear Power Plants”, esp. pages 4-5. http://adamswebsearch2.nrc.gov/idmws/doccontent.dll?library=PU_ADAMS^PBNTAD01&

ID=003970364

- Regulatory Guide 1.155, "Station Blackout." http://adamswebsearch2.nrc.gov/idmws/doccontent.dll?library=PU_ADAMS^PBNTAD01&

ID=003957121

- Regulatory Guide 1.9, "Application and Testing of Safety-Related Diesel

Generators in Nuclear Power Plants."http://www.nrc.gov/reading-rm/doc-collections/reg-guides/powerreactors/active/01-009/01-009.pdf

- American Society of Mechanical Engineers document ASME OM-S/G 2007, "Standards and Guides for Operation and Maintenance of Nuclear Power Plants," is also in use at nuclear power plants. Part 16 of this document applies to Page 3EPA-HQ-OAR-2008-0708-DRAFT-0362 emergency diesel generators. This document has not been formally approved by the NRC, but NRC staff participated in its development.

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