NRC-90-0055, Responds to Generic Ltr 89-19, Request for Action Re Resolution of USI A-47 - Safety Implications of Control Sys in Lwrs. Overfill Protection Sys Adequately Separated from Main Feedwater Control Sys

Responds to Generic Ltr 89-19, Request for Action Re Resolution of USI A-47 - Safety Implications of Control Sys in Lwrs. Overfill Protection Sys Adequately Separated from Main Feedwater Control Sys

ML20012D436
Person / Time
Site:	Fermi
Issue date:	03/19/1990
From:	Orser W DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CON-NRC-90-0055, CON-NRC-90-55, REF-GTECI-A-47, REF-GTECI-SY, TASK-A-47, TASK-OR GL-89-19, NUDOCS 9003270322
Download: ML20012D436 (4)

Text

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' William S, orser di"~ Wce President

. Nuclear. operations 1

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g@ ge g gcy oan 481 ' oeneration March 19, 1990 NRC-90-0055 U. S. Nucicar Reguletory Commission Attn Document Control Desk Washingt on, D. C. 20555

References:

1) Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43 4 2) NRC Generic Letter 89-19. " Request for Action Related to Ret olution of Unresolved Safety Issue A-47-Safety Implication of Control Systems in LWR Nuclear Power Plants",

dated September 20, 1989 3). Detroit Edison Letter NRC-89-0204, dated September 12, 1989

4) Detroit Edison Letter, NRC-89-0207, dated September 28, 1989 x

5) NRC Letter (TAC Nos. 59611 and 74835),

dated December 4, 1989

Subject:

Response to NRC Generic Letter 89-19 Detroit Edison has reviewed the Generic Letter 89-19 (Reference 2) which was r_eceived on October 9,1989. This Generic Letter requests licensees to take actions related' to resolution of USI A-47 as recommended in Enclosure 2 of the Generic Letter.

Detroit Edison has reviewed the Generic Letter's requirement to provide automatic reactor vessel overfill protection to mitigate main j

feedwater (MFW) overfeed events. Fermi 2' has an automatic overfill

- O Q. protection system which is initiated on a. reactor vessel

$8 high-water-level signal on e 1-out-of taken twice initiating logic.

O$ and is classified as a " Group I" plant in the Generic Letter. The Generic Letter has concluded that this design is acceptable provided NU that (1) the overfill protection system is separate from the MFW Q@ control system, and (2) the plant procedures and Technical 51 Specifications include requirements to periodically verify operability Oct of the system.

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e. 0. 0. At Fermi 2, the overfill protection system is adequately separated f rom the MFW control system such that both of the systems are not  ;

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p' f powered Yiom the"same source, not located.-in othe same cabinets and not routed'EsoLthat a . fire is likely to 'af fect both systemsW While- the

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.-level :of design does not preclude any possible ~ situation' from h

M, preventing the trip, it do.es protect against the most probable single.

R i failures: (e.g'.. fuse or; electrical component) and guards 'against hg maintenance. errors,?with the .MFW Control System .~and- overfill-F s prot ection.1 spstem being located in separate = cabinets. ; LIn addition,

,FermiL 2 surveillance procedures and Technical Specifications have-

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' requirements to periodically? verify the operabilityiof: the system..

_4 1Thus.;both of=the provistone of GL 89-19'for;" Group I" plants are ^

P satisfied by Fermi"2. The system design has been previoualy evaluated :

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-as' acceptable,by the NRC in NUREG-0798, Safety Evaluation Report for o ' Fe rmi12. ' '

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Edison has-reviewed plant operating procedures and operator f' ' t.raihingliniregard to- reactor vessel overfill events that may occur p ,

ivia:the condensate system-pumps during. reduced system pressure 0i operation. Procedures clearly state the operating band for ' water s

level. ' Aclesson plan provides information on'the capability of the ~

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fi;r condensate system pumps. . There are simulator scenarios involving 1oes

.of feedwater pumps Jin which the instructor stresses the potential n _ problems caused by a reactor pressure.vesael overfill situation and.

W, operator actions which should be taken to prevent this from occurring. : Additionally,; following. review of this Generic Letter, two

g. simulator evaluation. scenarios were revised to specifically evaluate q^

operator performance during' poteatial reactor vessel ^ overfill events.

S' ;The: review has concluded that Fermi-2 procedures and operator training- ~l y

are adequate to assure that the operators can successfully recognize '

and prevent such overfill events.

l Although not , requested by the Generic Letter, Detroit Edison has also reviewed High Pressure Coolant Injection (HPCI) and Reactor Core  ;

Isolation Cooling (RCIC) Systems high reactor vessel water level i

- trips. These. trips are similar to MFW trips except the initicting [

logic' is .2-out-of-2 which is classified as " Group II" in the Generic (

' Letter. 'Our review-has concluded that for both HPCI and RCIC systems. (

the protection system is separate from the control systm and the high re' actor vessel trips are adequately addressed in plant procedures and , ~~

Technical 1 Specifications. Therefore, HPCI and RCIC also satisfy the' 4

provision of this Generic Letter.

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Hence, as discussed above, Fermi 2 design is consistent with the j 1

recommendations of this Generic Letter and no additional actions are required.to be implemented. q L l A plant specific control systems f ailure analysis was recently conducted for Fermi 2. The results were submitted in References 3 and ,

4 and the NRC issued its Safety Evaluation Report in Reference 5.

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-[ USNRC Mareh 19.:1990

. NRC-90-0055 Page 3 If you have any questions, please contact Mr. Girija Shukla at (313) 586-4270.

Since rely.

l cc A. B. Davis R. W. DeFayette W. G. Rogers J. F. Stang 4

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(. . ..

• c r; 98 ~ 11SNRC .

!: Ma ch-19, 1990

' NRC-90-0055' Page 4 t:

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< I,: WILLIAM S. ORSER, do hereby af fizu that the foregoing statements are based on facts and circumstances which are true and accurate to the best of my knowledge and belief.

c h WILLISM S. ORSER p Vice President.

L Nuclear Operations I'

On this Y[, day of -Q/[f_,1990,;before me persona 11y' app'eareil William S. Ort. teing first duly sworn and says that he executed the foregoing as his free act and deed.

4. f Notstry Pufic'

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' WU.y L CARtSON Notary Public.Woyne County, MI MyCommissionEuphes228,1991 f.

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