ML20154A420

Safety Evaluation Supporting 831108 Response to Generic Ltr 83-28,Items 3.1.1,3.1.2,3.2.1,3.2.2 & 4.5.1 Re post-maint Testing & Reactor Trip Sys Reliability

ML20154A420
Person / Time
Site:	Millstone, Haddam Neck, 05000000
Issue date:	11/04/1985
From:	NRC
To:
Shared Package
ML20154A404	List: ML20154A401 ML20154A405 ML20154A420
References
GL-83-28, TAC-54082, NUDOCS 8603040037
Download: ML20154A420 (4)

Text

w .

- w

,v S c - L av b.:.;i.p a.q. . ,>.) ..

SAFETY EVALUATION GENERIC LETTER 83-28,_ ITEMS 3.1.1. 3.1'2, 3.2.1, 3.2.2, and 4'5.1 _

NORTHEAST UTILITIES MILLSTONE NUCLEAR POWER PLANT, UNIT 1

.. DOCKET NO. 50-245 1.0 Introduction On February 25, 1983, both of the scram circuit breakers at Unit 1 of the Sales Nuclear Power Plant failed te open upon an automatic reactor trip ;

- signal from the reactor protection system. This incident occurred during '

the plant startup, and the reactor was tripped manually by- the operator about 30 seconds after the initiation of the automatic trip signal. The failure of the circuit breakers has been determined to be related to the sticking of the undervoltage trip attachment. Prior tio this incident, on

' February 22, 1983, at Unit I of the Sales Nuclear Power Plant . an auto-matic trip signal was generated based on steam generator low-low level during plant startup. In this case the reactor was tripped manually by the operator almost coincidentally with the automatic trip.

.Followin2 these incidents , on February 28, 1983, the NRC Executive Director for Operations (E00), directed the staff to investigate and

, report on the generic isnplications of these occurrences at ITnit 1 of the Salem Nuclear Plant. The results of the staf f's inquiry into the generic

. 1splications of the Sales unit incidents are reported in NUREG-1000

" Generic !apitcations of ATWS Events at the Sales Nuclear Power Plant.E As a result of this investigation, the Of rector, Division of Licensing,

' Office of Nuclear Reactor Regulation requested (by Generic Letter 83-28 dated July 8,1983) all licensees of operating reactors, applicants for an operating license, and holders of construction permits to respond to cer-tain generic concerns. These are categorized into four areas; (1) Post-Trip Review, (2) Equipment Classification and Vendor Interface, (3) Pos't-Maintenance Testing, and 4) Reactor Trip System (RTS) Reliability Improvements. Within each o(f these areas various specific actions we delineated. .

This safety evaluation -(SE) addressed the following actions of Generic Letter 83-28:

3.1.1 and 3.1.2, Post-Maintenance Testing (Reactor Trip System Components) -

3.2.1 and 3.2.2, Post-Maintenance Testing (All Other Safety-Related Components)

~ ~ gRO3040037 06022,1ADocg 95999 33 p

i PDR em

- , ~w.-,,m-- --m , . - - , - , _ - --,,e - - - , - - - - - - - - - , -- ,,-- , e - - - - - -

• = .- .

. * ,_ ,s

. . . c ,,

~. .

~:

Safety Evaluation 2 Y

• 4.5.1, Reactor Trip System Reliability (System Functional Testing) ,,

I i

By a letter dated November 8,1983, Northeast Utilities (the licensee)

, cescribed their planned or completed actions regarding the above items for  :

.. Hillstone Nuclear power plant, Unit 1.  !

m. 2.0 Evaluation f

.i 2.1 General i Generic Letter 83-28 included various NRC staff positions regarding the specific-actions to be taken,by operating reactor Itcensees and operating g license applicants. The Generic Letter 83-28 positions and discussions of  :

Itcensee compliance regarding Actions 3.1.1, . 3.1. 2, 3. 2.1, 3.2.2, and j 4.5.1 for Millstone Unit 1 are presented in the sections that follow.

~

2.2 Actions 3.1.1 and 3.1.2, post-Maintenance Testina (Resetor Trin

_ System Components) .

position 2

Licensees and applicants shall submit the results of their review of

._ . test and maintenance procedures and Technical Specificaticns to assure that post-maintenance operability testing of safety related ,

components in the reactor trip systenL (RTS) is required to be con-ducted and that the testing demonstrates. that" tNe .Jequipment is

_ capable of performing its safety functio'ns .before bein'g returned to se rvi ce.

- r; ,

Licensees and applicants shall submit the results of their check of

. vendor and engineering recommendations (regardinf safety-related components in the RTS) to ensure that any appropriate test guidance

_. is included in the test and maintenance procedures or the Technical Specifications, where required.

Ofscussion The licensee's response states that a review of all test and main-tenance procedures and Technical Specifications indicate that post-maintenance operability testing of reactor trip components is re-

. quired in all cases. In general, this is accomplished as part of the restoration sections of procedures, retests required after mainten-ance, or performance of surveillance procedures as required by~

Technical Specifications.

mess 89 D

.s

_. . .f.% ' ' ;.  :

5 -G .

Safety Evaluation _ .

.3 The licensee's response also confirms that all known vendor and engineering recommendations have be.en included in test and mainten-ance procedures. The licensee further states that no recommendation in'volved potential changes to Technical Speciff, cations. -

~ Based on the above, the licensee has complied with the' NRC Staff posttion for Actions 3.1.-1 and 3.1.2 of Generic Letter 83-28.

2.3 Actions 3.2.1 and 3.2.2, Post-Maintenance Testing (All Other Safety _^

Related Components) ,

Position Licensees and applicants shall submit a report' documenting the ex-tending of test and maintenance procedures and Technical Specifica-tions review to assure that post-maintenance operability test.ing of all safety-related equipment is required to be conducted and that the testing demonstrates that the equipment is capable of performing its safety function before being returned to service.

~-

Licensees and applicants shall submit the results of their check of vendor and engineering recommendations (regarding all other safety related components) to ensure that any appropriate test guidanca is included in the test and maintenance procedures or the Technical Specifications, where required.

Discussten - -

The licensee's response stated that the review of- test and mainten-ance procedures and Technical Specifications for all other safety -

related ' equipment is , required in all cases. Tne licensee response also confirmed that a check of vendor ard engineering recommendations was conducted to ensure they have beec included in test and sainten-ance procedure or Technical Specifications. .

Based on the above, the licensee has complied with the NRC Sta'ff position for Actions .3.21 and 3.2.2 of Generic Letter 83-28.

~

2.4 A tion 4.5.1, Reactor Tr1p System Reliability (System Functional

_ Testing)

Position -

On-line functional testing of the reactor trip system, including independent testing of the diverse trip features, shall be performed.

The diverse trip features to be tested include the breaker under-voltage and shunt trip features on Westinghouse, B&W, and CE plants; the circuitry used for power interruption with the silicon controlled

- rectifiers on B&W plants; and the scram pilot valves and backup scram valves (including all initiating circuitry) on GE plants.

~

.  ;)

. . ' . s . ;. e.

._ - fi n.d::

7

_ Safety Evaluation 4 -'

Discussion .

The licensee's response stated that on-line functional testing of the reactor trip system 15 performed in the frequencies defined ~by the Te3nical Specifications. The trip signal is input at the. initiating switch, and therefore demonstrates operability of all initiating circuitry and the scram pilot valves. As of November 8, 1983, the licensee was performing an investigation to determine the optimum surveillance requirements for the backup scram valves. _.

Ir. a letter date.1 March 16,1984, the licensee stated that they are implementing a procedure to fully test the backup scram valves and the ATWS backup scram valves. This testing will be performed during refueling outages. In a memorandum dated N6vember 16, 1984 from R. W. Houston, NRR, to G. Lainas, T. Novack, and D. Crutchfield, NRR, justification has been provided to not require modification of backup

• scram system to provide on-line testability.

Based on the above, the licensee has complied with the NRC staff posit,ior.s for Action 4.5.1 of Generic Letter 83-28.

3.0 Conclusion ~

Based upon the foregoing discussions, the staff concludes that the lican-see is in compliance with Actions 3.1.1, 3.1.2. 3.2.1, 3.2.2, and 4.5.1 of

,_e.

Generic Letter-83-28.

1 f

Date: November 4,1985 }

i

. Principal Contributor: Jonn A. Schumacher ORp e

m e

, em O

e m

m M