ML20246D451

Advises That Util Alternate Rod Insertion & Recirculation Pump Trip Sys Design & Conformance to ATWS Rule (10CFR50.62) Basic Requirements & Objectives Not Acceptable

ML20246D451
Person / Time
Site:	Brunswick
Issue date:	08/21/1989
From:	Adensam E Office of Nuclear Reactor Regulation
To:	Eury L CAROLINA POWER & LIGHT CO.
References
TAC-73351, TAC-73352, NUDOCS 8908280101
Download: ML20246D451 (4)

Text

p. . . .w pc < /

%  : w ,r

- 4 o

~ UNITED STATES g

h ]; [;}y, 7~ -

g ~ NUCLEAR REGULATORY COMMISSION g- WASHINGTON, D. C. 20555 h.... #f t

August 21, 1989 l

,7 '

Docket Nos. 50-325' and.50-324' Mr. Lynn W. . Eury

-Executive Vice President

' Power Supply:

m Carolina Power.& Light Company iPost Office. Box.1551 Raleigh, North Carolina 27602

Dear Mr. ,

Eury:-

L

SUBJECT:

' ANTICIPATED. TRANSIENTS WITHOUT SCRAM.(ATWS) SYSTEMS DESIGN DEFICIENCY -

BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 (TACS 73351/73352).

On April;14,1987,~ Carolina Power & Light Company (CP&L) submitted a' letter .

providing the NRC staff with details of the Brunswick Steam Electric Plant (BSEP) alternate rod insertion (ARI) and recirculation ump trip (RPT) ' systems'

. design and conformance to.the ATWS Rule (10 CFR 50.62) + basic. requirements and L

objectives.

In early February 1989, the NRC reside,t inspector performed an inspection on the "as-built" SSEP ATWS ARI/RPT syst *.. and noted that the ARI logic and solenoid valves were powered from the same distribution panel as one' division

'd of the reactor trip system (RTS) analog transmitter trip units. This raised NRC = concern regarding the independence of the ARI system power supply from-

'the RTS.

During-a conference call held on March 1,1989, the staff requested CP&L to

. provide more detailed drawings. related to the ARI system and RTS power supplies.

Based'on the drawings provided on March 15, 1989, the staff reconstructed the

.. "as-built" power supply arrangement. into a simplified block diagram as shown in Figure 1 (see Enclosure 1). This block diagram was provided to CP&L by the Resident Inspector and was verbally agreed to by CP&L on April 1, 1989.

As illustrated in Figure 1, the_BSEP's ARI logic and final actuation devices (i.e., ARI solenoid valves) are' powered from a DC Distribution Panel 12A,

. feeder No. 2. The power to the RTS analog transmitter trip unit (ATTU) is also supplied from this same Distribution Panel 12A, on feeder No. 19, which is contrary to the commitment stated in. the CP&L's letter dated April 14, 1987.

Furthermore, the staff concludes that the "as-built" ARI system power supply arrangement is not in agreement t.ith the ATWS Rule Guidance regarding System ano Equipment Specifications. The ATWS Rule Guidance, published as

" Supplemental Information" when the final rule was noticed in the Federal Register (49 FR 26036) on June 26, 1984, states, in part, that the diverse

. reactor trip system (diverse scram system or alternate rod injection) logic a 8908280101 890821 '.

<gDR ADOCK0500tg4 g ]

9

t .,w

.o l . . .

Mr. Lynn W. Eury ' ^"9" ' '

and actuation device power must be from an instrument power supply independent

'from the power supplies for the existing reactor trip system. Existing RTS and instrument channel power supplies may be used, provided the possibility of common mode failure is prevented.

Based on the ATWS Rule Guidance, the staff has also provided clarification of )

the Guidance to the B&W Owner's Group on various acceptable design options that i can be used to resolve the power supply independence issue. The following i options are acceptable to the staff:

1.: Provide a non-class .1E de power supply with non-class IE. battery backup that provides power to the ARI system logic and ARI solenoid. valves.

2. . Upgrade the ARI system to a class IE system that is powered by RTS power ,

sources and.show, through a failure modes and effects analysis, that common  !

mode failures will not propagate through the power supplies and disable l both the RTS and the ARI/RPT system. j for you information, we are enclosing a copy of the staff's clarification letter to the B&W Owner's Group,' dated September 7, 1988 (Enclosure 2).  !

The staff has concluded that the "as-built" ARI system power supply arrangement l at BSEP is not in agreement with the ATWS Rule Guidance or the commitment made ,

in your April 14, 1987 letter that the ARI system will be designed so the t

' ARI power supply is independent of any RTS components. Therefore, within 15 days of receipt of this letter, you are requested to advise us if you plan to meet the ATWS Rule Guidance and your earlier commitment. If so, within 60 days of receipt of this letter, you are requested to 3rovide the NRC with your plan and its schedule for implementation to resolve t11s issue. You should consider the options above in preparing a plan to meet the ATWS Rule Guidance.

The reporting and/or recordkeeping requirements contained in this letter affect fewer than 10 respondents; therefore, OMB clearance is not required under P. L.96-511.

Sincerely, $/hren 4v' Nh Elinor G. Adensam, Director Project Directorate 11-1 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation

Enclosures:

As stated-cc w/encls:

.See next page DISTRIBUTION p Docketfile T. Le.

0GC NRC & LPDRs P. Anderson B. Grimes, 9/A/2 f PDII-1 Rdg File Jordan, MNBB.3302 S. Varga, 14/E/4 \

L. Spessard, MNBB-3701 G. Lainas ACRS(10)

E. Adensam M. Sinkule, RII OFC :LA . :0GC-  : P5:NRR :D 21

.....:.. 2 g _::PM:FD21 NAME :PA drson :NLe:jd  :*MYoung :G Juas :EAd nsam  :  :

F"~%~~~~~~L .a.- ;R"::::~ ~~ *::W":"" ;::X"""; """"~ ~~ ; ~ ~ ~""" ~ \

p g, L

[ . s ,, _ '

I .- Mr. L. W. ' Eury Brunwick Steam Electric Plant I

Carolina Power & Light Company Units I and 2 cc:

Mr. Russell B. Starkey, Jr. Mr. H. A. Cole Project Manager Special Deputy Attorney General Brunswick Nuclear Project State of North Carolina i:

P. O. Box 10429 P. O. Box 629 Southport, North Carolina 28461 Raleigh, North Carolina 27602 Mr.. R. E. Jones, General Counsel Mr. Robert P. Gruber Carolina Power & Light Company Executive Director P.'O. Box 1551 Public Staff - NCUC Raleigh, North Carolina 27602 P. O. Box 29520 Raleigh, North Carolina 27626-0520 Ms. Frankie Rabon Board of Commissioners P. O. Box 249

Bolivia, North Carolina 28422 Resident Inspector #

U. S. Nuclear Regula. tory Comission Star Route 1 P. O. Box.208 Southport, North Carolina 28461 1

Regional Administrator, Region II U. S. Nuclear Regulatory Commission 101 Marietta Street, Suite 2900 Atlanta, Georgia 30323 Mr. Dayne H. Brown, Chief Radiation Protection Branch j Division of Facility Services N. C. Department of Human Resources 701 Barbour Drive Raleigh, North Carolina 27603-2008 Mr. J. L. Harness Plant General Manager l Brunswick Steam Electric Plant P. O. Box 10429 Southport, North Carolina 28461 ,

j i

1 1

^

Enclosure 1

,6 -

PlV. I. 480 VAc Mcc gT5 ti f 5 6AT7EAY Bm64f BArtray BATTERY M/6r 5sr - PeWFM ""

LA cogy cH ARer 5A 24-1 c84Au re R LA-i ",

s A - s.

yy,, ,, V- l + i e ir RTS * \10lMt Yh' LoGsc V8TAL

'I1F/tse vpc swiTcHaeAnD 2A pweg sist, PMeL5

• 110VAc DC DISTR Dc, DISTR, pat 4EL 4 A PA4EL liA rerpia m ocA Fersex reessa

1. 6 TM (it et

, n 9 4 n RT5 RT5 Ecc5 RTS A u Sytreet vpRTe CAL 8A'KUI DiV. I DW I. up(

SoAAp I'SAS ATTU ATTu- 3.c,y3ty,3 YA'#I AL5eFd ARE Arro FlcoRE r f. Steestrico atock orAsers or tsweg suppty ARRA44EMENT FoA AAI Ado RT5,

m.

~

Encl sure 2 September 7, 1988

-L.

Mr. L. C. Stalter' Chairman BWDG/ATWS Cosmittee i Davis Besse Nuclear Power Station 5501 North S. R. 2 (Mail Stop 3205)

- Oak Harbor Ohio 43449

SUBJECT:

AUGUST 17, 1988 B&W/NRC ATWS MEETING The purpose of this letter is to susmarize major points addressed during the meeting which was held with the B&W ATWS owners group on August 17, 1988 to discuss the overall ATWS Rule requirements including power supply independence as related to the staff generic B&W ATWS SER.

After a presentation by you and other merters of the owners group, the staff

.provided clarification on various acceptable design options that would resolve the power supply independence issue. We concludeo that each licensee should consider each option as it appites at each specific plant. The following options were presented by the staff:

1. Provide a DSS /AMSAC. design as depicted in the viewgraph (Figure 1) presented at the meeting. This viewgraph shows the DSS /AMSAC being i powered via a 480 volt bus with its own independent (i.e,, not associated with the RTS) non-Class IE battery, rectifier and charger that provide 120 YAC to the ATWS circuitry. l l

2. Provide a power source to the DSS as discussed above but non-battery l

' backed. In addition, provide a discussion showing that for all loss of offsite power scenarios, the rods will be released through a loss of voltage to the 480 YAC holding mechanism. Furthermore, show that the Emergency Feedwater Initiation and Control System (EFIC) design  :

(oritsequivalent)meetstherequirementsoftheATWSRule(i.e.,

show that EFIC and AMSAC are equivalent in that they both perform i the same function). If EFIC is powered through RTS 120 VAC buses i then show by a failure modes and effects. analysis that common mode  :

failures will not propagate through the power supplies and disable  ;

both EFIC and the RTS. For this case, the EFIC system has to be a Class 1E system.

3. Provide a Class 1E DSS that is powered by 'RTS power sources and show i through a failure modes and effects analysis that costa mode failures  ;

will not propagate through the power supplies and disable both DSS and  !

the RTS. EFIC is to be treated as discussed in (2) above.

D91MrS56r WP '- - - - - - - _ - -

L. C. Stalter Based on our discussions to date, it is appamnt that the power supply issue has delayed the implementation of the ATWS system at the B&W plants. We are concerned over this delay and strongly recourend that the B&W licensees proceed with their planned ATWS implementation utilizing the option that will support the quickest resolution of the power supply independence issue. Option 1 will provide the most expeditious resolution and would clearly esot the power supply independence guidance published with the ATWS Rule. The approaches specified in options 2 and 3 are significantly more complex in that they involve the development of specific detailed failure modes and effects analyses. Such approaches could significantly delay resolution of the power supply independence issue (separation issue) and may ultimately lead to non-t.cceptance by the staff should unacceptable failure modes be identified.

Following receipt of each plant specific " conceptual" design package, the staff plans to review the package within 30 days and to approve, or disapprove with coments, the proposed design. This will be followed by the issuance of a safety evaluation upon receipt of a more detailed design package. Since the generic design review has now been completed and the options for resolving the power supply issue are sufficiently clear, we have concluded that the staff safety evaluation does not have to precede the implementation of the required-ATWS equipment. In other words, our safety evaluation would be a " post-imple-mentation" review. All B&W plants, upon receipt of the NRC approval of the conceptusi design, should install the ATWS equipment during their next refueling outage. In special cases where this can't be accomplished, it should be brought to the attention of the staff for their review and approval per 10 CFR 50.62(d).

Sincerely, N

Gary Holahan, Acting Director Division of Reactor Projects - III, IV, Y and Special Projects Office of Nuclear Reactor Regulation

Enclosures:

As stated l

l i

i

tw l 11

.;1 ...

1 ---

=

-a t

r _

i ..........,

w3 i

$3-

~

! e

,L ._ '- 1 i 5

.i \

I i41

-l i I I i

i 4 3 e5 e 4o , ,e j-g

] _ i

g. .......

g g - .......

- E v  :

'4 - l 7

l 7 I e

,l -

i

e

= l _U -

• i'

- [ '

! ~

id  !

W _ i 1_l5

=

__ = -e  :

- e l i l l I  !

i

_ =

.I -

r i

i l -a A

/ I O

. m*

s.su.

g- n -

1

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _