ML20236B464

Comments on Proposed Rev 3 to Reg Guide 1.9, Selection, Design,Qualification,Testing & Reliability of Diesel Generator Units Used as Onsite Electric Power Sys at Nuclear Power Plants. Reg Guide Does Not Provide Flexibility

ML20236B464
Person / Time
Site:	Millstone, Haddam Neck, 05000000
Issue date:	03/08/1989
From:	Mroczka E CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Meyer D NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
FRN-53FR45831, FRN-57FR14514, REF-GTECI-B-56, REF-GTECI-EL, RTR-REGGD-01.009, RTR-REGGD-1.009, TASK-B-56, TASK-OR 53FR45831-00008, 53FR45831-8, AE06-1-007, AE6-1-7, B13113, NUDOCS 8903210102
Download: ML20236B464 (8)

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March 8,-1989 Docket Nos. 50-213 50-245 50-336 sc 10-4R 813113 Re: Draft Regulatory Guide 1.9 RS 802-5 Mr. D. L. Meyer, Chief Regulatory Publications Branch f N k Office of Administration and } l j / k/ l Resources Management I i

U.S. Nuclehr Regulatory Commission '

Washington, DC 20555 '

Dear Mr. Meyer:

i Haddam Neck Plant ,

Millstone Nuclear Power Station, Unit Nos. 1, 2, and 3 ~'

Comments on Proposed Revision 3 to Reaulatory Guide 1.9 On November 14, 1988,U) the Nuclear Regulatory Commission published for '

public comment Revision 3 to Regulatory Guide (RG) 1.9, " Selection, Design, Qualification, Testing, and Reliability of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power Plants." Connecticut Yankee Atomic Power Company (CYAPC0) and Northeast Nuclear Energy Company (NNE hereby respectively submit the following comments. On January 18,1989,g the comment period was extended to March 14, 1989.

Backaround i

Proposed Revision 3 to RG 1.9 has been prepared for the resolution of Generic )

Safety Issue B-56, " Diesel Generator Reliability." The NRC Staff has previ- {

ously addressed diesel generator design, reliability, and operational aspects )

by using IEEE Std 387-1984, Revision 2 of RG 1.9, RG 1.108 (which is being l withdrawn), and Generic Letter 84-15. The purpose of this Revision 3 to RG 1.9 is to integrate into a single regulatory guide the guidance previously dispersed in these multiple documents.

l (1) 53 Federal Register 45831, November 14, 1988.

(2) 54 Federal Register 2009, January 18, 1989.

8903210102 890308 ,

PDR REGGD 01.009 C PNU

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8 Mr. D. L. Heyer  !

B13113f? age 2 March 8, 1989 i

General Comments First, NNECO and CYAPC0 recommend that the proposed Revision 3 to RG 1.9 be .

revised to incorporate additional flexibility to take into consideration the age of the emergency diesel generator (EDG) and the manufacturer's recommenda- j tions. Operations, instructions, and maintenance manuals provided with EDGs )

from the manufacturer should be the source documents for establishing preven- '

tative maintenance schedules and surveillance requirements. All EDGs have'not been built to the same specifications and criteria and therefore should not be arbitrarily subjected to the same testing requirem:.nts. This section should include instead a reference to the recently published standard, ASME/ ANSI OM-16, Inservice Testina and Maintenance of Diesel Drives in Nuclear Power Plants. This standard provides requirements for in-service testing and j

maintenance of diesel drives that are utilized in nuclear power plants. These -

diesel drives perform a specific function in shutting down a reactor or in  ;

mitigating the consequences of .an accident. This standard covers the period j beginning with the diesel drive start-up and continuing through the life of i the plant. Test intervals, te::t methods, data requirements, and criteria for '

evaluation of the test results are provided.

Secondly, the draft RG 1.9 appears to direct nuclear plants to dedicate a f great deal of additional resources to the review and evaluation of EDG perfor- i mance. CYAPC0 and NNECO already dedicate a significant amount of resources to EDG monitoring and evaluation due to RG 1.08, Generic Letter 84-15, Institute of Nuclear Power Operation and Electric Power Research Institute documents and the Nuclear Plant Reliability Data System. Existing EDG monitoring programs have successfully demonstrated reliability goalsperfgan'9 In addition, CYAPC0 and NNEC0 use probabilistic risk assessment (PRA) as a means of determining the impact of the EDG failure on plant risk. The EDG failure .

rates in the PRA models are updated as necessary to reflect current assessed reliability. Should the EDG reliability performance substantially change, this would subsequently be reflected in the PRA, and brought to management attention. .

r l While CYAPC0 and NNECO agree that the EDGs are vitally important to the safe operation of nuclear power plants, the draft RG 1.9 does not provide utilities with the flexibility needed to integrate advantageous features of this program l into existing EDG reliability programs.

Specific comments on RG 1.9 are attached for your consideration.

(3) Institute of Nuclear Power Operation Nuclear Power Plant Performance Indicators 1988 Mid-Year Report published the following EDG unavailability data for July 1987 through June 1988 for each unit:

Haddam Neck Plant, 0.002; Millstone Unit No.1, 0.002; Millstone Unit No. 2., 0.000. Please note that adequate data was not available on Millstone Unit No. 3 to calculate EDG unavailability data.

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Mr.'D. L'. Meyer B13113/Page 3 March 8, 1989 We trust that these comments will be useful in the finalization of Revision 3 l to RG 1.9.

< Very truly yours, CONNECTICUT YANKEE ATDMIC POWER COMPANY NORTHEAST NUCLEAR ENERGY COMPANY E. 'U./Mroczka //

Senior Vice President cc: U.S. Nuclear Regulatory temmission, Do:umeret Control Desk W. T. Russell, Region I Administrator M. L. Boyle, NRC Project Manager, Millstone Unit No. I G. S. Vissing, NRC Project Manager, Millstone Unit No. 2 D. H. Jaffe, NRC Project Manager, Hillstone Unit No. 3

, A. B. Waag, NRC Project Manager, Haddam Neck Plant l W. J. Raymond, Senior Resident Inspector, Millstone Unit Nos.1, 2, and 3 J. T. Shedlosky, Senior Resident Inspector, Haddam Neck Plant A. W. Serkiz, Regulatory Publications Branch, U.S. Nuclear Regulatory Commission, Office of Administration and Resources Management A. Marion Nuclear Management and Resources Council 1776 Eye Street, NW Suite 300 Washington, DC 2006-2496

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Docket Nos. 50-213 50-245 t .

50-336 I' 50-423 B13113 l

Attachment Specific Comments on RG 1.9 a

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March 1989 w; _

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Mr. D. L. Meyer l Attachment /B13113/Page1 March 8, 1989 Introduction. Paraaraoh 7 The words " degrade with age" are not meaningful unless they are related to

. potential failure effects.

CYAPC0 and NNECO recommend the following change: "Unless the diesel genera-tors are properly maintained, age-related changes 'may progress to the point where a required operating function may be threatened."

Discussion. Paraaraoh 5 The wording suggests that the generator differential current trip may result from an overspeed condition. This is not the case, as the differential protection serves to detect electrical failures within the zone protected during all starting and running conditions of the diesel.

Discussion. Paraaraoh 6 Provided that the reliability goa'l of the diesel can be maintained at the target level, it should not be necessary to limit the number of automatic trips provided under an " accident" scenario. Spurious or unwanted trips during surveillance testing will result in a decrease in reliability which may still, hcwever, remain above the target level. The advantages of adequate protective devices in limiting equipment damage and allowing a more ready return to service could more than offset potential interference with the successful functioning of the unit. The target reliability goal is demon-strated by surveillance testing when all of the protective trips are in service.

Reaulatory Position. Section 10.2.1.1 This section needs to be clarified. The first sentence states that the diesel i should start from standby and attain required voltage ano frequency within

" acceptable time limits." The second sentence states that the diesel be slow l started and reach rated voltage and frequency on a "prespecified schedule" l selected to minimize stress and wear. Are the " acceptable time limits" and "prespecified schedule" one in the same? Acceptable time limits may be interpreted as the time requirements for the diesel to attain rated voltage and frequency to accept safety-related loads during an accident to satisfy the safety anelysis. Acceptable time limits for a slow start should be a manufac-turers' recommendation. There should be differentiation between a slow start and a fast start.

In addition, this section should allow for EDGs that cannot be slow started.

For instance, Millstone No.1 EDG cannot be slow started due to the design of the speed and voltage control systems. During each test start, the engine is o

et Mr. D. L. Meyer Attachment /813113/Page 2 March 8, 1989 l brought up to full speed and voltage at tne same rate as during an emergency l

demand start.

l Reaulatory Position. Section 10.2.1.2 i

This monthly load test should depend on manufacturers' recommendations. Not all manufacturers recommend full load tests; at Millstone Unit No. 2 the manufacturer recommends a 75 percent load test to minimize stress.

The basis for establishing a " prescribed schedule" for diesel generator loading and unloading is reasonable. However, the section should elaborate more on the definition of a " prescribed schedule." This should also be in accordance with manufacturers' recommendations.

Reaulatory Position. Section 10.2.2 The cr'.,eria for accelerated testing should not be based solely and uncondi-tionally on test failure statistics. If test failures can be attributed to isolated failures of components of the diesel system, increasing the test frequency will reduce the reliability of the diesel from additional unneces-sary starts rather than improving confidence. This section should be worded to provide flexibility in specifying acceleded testing when good engineering judgment determines it to be prudent.

Reaulatory Position. Section 10.2.3,.1 It is understood that manual prelubrication in accordance with manufacturers recommendations is allowed so as to prevent unnecessary stress to the bearings from a dr ter 84-15.g'ptart. This was described in NNECO's response to Generic Let-Reaulatory Position Section 10.2.3.2 Loading the generator to its continuous rating in less than its design acci-dent sequence time every 6 months is unnecessary and causes excessive stress on the generator, and is inconsistent with ensuring maximum generator avail-ability.

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W. G. Counsil letter to D. G. Eisenhut, "Information Requested by Generic Letter 84-15," dated February 4, 1985.

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a s Mr. D. L. Meyer--

Attachment /B13113/Page3 March 8, 1989 Reaulatory 30sition. Section 10.2.4 CYAPC0 a'nd NNEC0 question the need to perform a simulated loss of off-site 3 power test (Section 10.2.4.1) separate from an autostart (SIAS) signal test (Section.10.2.4.2)sincethetwoareperformedtogether(Section10.2.4.3).

Reaulatory _ Position. Section 10.2.4.2 This section should state that it is only applicable if the diesel gets an i autostart signal during' an SIAS. This is not the case at Millstone Unit No. 2.

Reaulatory Position. Section 10.2.4.3 This section should provide flexibility to remove some emergency loads during the test by placing breakers in test position; for example, to prevent the possible undesirable starting of emergency injection pumps during shutdeun conditions.

Reaulatorv iosition Section 10.2.4.6 This test should 'only be part of preoperational testing, not every refueling.

This test stresses the engine 9 necessarily and excessively for limited informational gain.

Reaulatory Position. Section 10.2.4.9 The method to demonstrate that all diesel generator trips are bypassed (except

'or engine.overspeed and generator differential) should not create the poten-tial for the actual condition that causes a bypassed trip (i.e., do . not intentionally cause a low lube oil pressure or a high temperature condition).

A statement of caution should be included in this section.

Reaulatorv Position. Section 10.2.4.11

. This test is also excessive and unnecessary for limited informational gain.

Reaulatory Position. Section 11 This section regarding environmental qualification is of little value if the diesels are located in mild environments such as those at Millstone Unit Nos. 1, 2, and 3 and the Haddam Neck Plant.

Reaulatory Position. Section 16 l The logging and reporting criteria is greater than what NNECO and CYAFC0 l consider adequate. Millstone and Haddam Neck use the Preventative Maintenance i

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, s l Mr. D. L. Meyer j Attachment /B13113/Page 4 l March 8, 1989 Management System and Plant incident Reports for documentation, failure analysis, and corrective actions. Extensive changes to existing procedures would be required to include those additional items the Regulatory Guide recommends.

! Reaulatory Position. SectioD_18 The entire section is wordy and provides too much detail regarding a diesel generator reliability program. The section goes beyond what is necessary for the Regulatory Guide. Reference to ASME 0&M Standard No.16 would provide a good example of what a reliability and maintenance program could contain.

Each individual utility should be allowed flexibility to establish its own diesel generator reliability program based on less specific guidelines. This section contains a good foundation that along with general guidelines, will allow the utility to establish a program specific to its diesels' needs. The requirements of the program should take into consideration the age of the plant, the design basis, und the applicable codes and standards for which the diesels were installed. This section must have enough flexibility to allow plants to add the most necessary, advantageous, and cost effective features from this proposed program to their existing EDG reliability programs. An extensive analytical program is not needed as long as the utility can maintain a reliability which exceeds that required for the applicable station blackout position.

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