ML20151G827

Requests Schedular Exemption from 10CFR50.49(j) Requirements So NRC Concerns W/Environ Qualification of Bunker-Ramo Penetration Equipment Do Not Delay Issuance of Full Power License for Unit.Safety Evaluation Encl

ML20151G827
Person / Time
Site:	Braidwood
Issue date:	04/07/1988
From:	Hunsader S COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), Office of Nuclear Reactor Regulation
References
4347K, NUDOCS 8804200154
Download: ML20151G827 (13)

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Commonwesith Edison i

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One First Natonal Plaza, ChcacMmnois 7 Address Reply to: Post Gffc4 Bd[F

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I Mr. T. E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory' Commission Washington, D.C. 20555 i

Attn: Decument Control Desk g

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Subject:

Braidwood Station Unit 2 Conditional Schedular Exemption for Environmental Qualification MRC Docket No. 50-457

Reference:

(a) March 23, 1988 S.C. Hunsader letter to T.E. Hurley j (b) April ', 1988 S.C. Hunnader letter to T.C. Murley

Dear Mr. Murley:

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The purpose ci this lettet11.4 to summarize a s? ries of events that i apply to the environsmtal qualific.! tion of one (1) piece of cIuipnent at Sraidwood Unit 2 and to provide the basis to request a conditional schedular exemption from a section of 10 CFR 50.49. This exemption is considered to be conditional in that the stated concerns appear to be readily resolvable.

However, it is possible that these concerns may not be resolved before the scheduled issuance of the Braidx)Ud Unit 2 Full power License. The concern presented by the NRC staff is'not believet to warrant delay in the issuance of that license.

On March 4, 1988 the NRC staff stated its opinion that one piece of equipment, installed in Braid d Unit 2, may not have enough supporting documentation to demonstrate environmental qualification. This piece of equipment is a Dunker-Ramo manufactured instrument penetration used to provide access through the Unit 2 containment wall in four (4) locations for

',, circuits that carry electrical signals from instrumentation inside the containment to scain control room indicators and protective circuitry. This penetration provides this function while maintaining the integrity of the containment pressure boundary. The penetration is identified at the four (4) locations in the' containment wall as 2S105E, 06E, 07E and 088. Though '

substantial, substative documentation exists to provide support for environmental qualif. cation, additional documentation has been determined to be necessary by the NRC staff to make the documented basis for environmental qualification ful:V auditable. This documentation was deemed to be necessary based upon th6 the low insulation resistance (IR) values presented in the Bunker-Ramo environmental qualification test report and whather these low IR values were attributable to the penetration or to the terminal block -

connected to the penetration and included in the test.

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During subsequent discussions on March 9 and 16, 1988 with the NRC staff, it was established that IR values, measured at the peak LOCA temperature or corresponding analysis regarding this peak condition, must be provided for the penetration module, for it to be con =idered fully qualified. IEEE 323-1974, states that IR values must ce measured during the course of the Design Basis Event (LOCA) test. NUREG-0588, Revision 1, dated i, July, 1981, states that "performance characteristics should be verified... periodically during test..." During the recent discussions, the NRC staff has indicated that these statements include the need to evaluate the IR at the peak LOCA temperature.

References (a) and (b) are evaluations of the existing

1. documentation which supports environmental qualification. The information provided in these documents establishes the "qualifiability" if not the full qualification of the penetration. Included as Appendix "A" is an evaluation performed as a part of the review to justify continued operation of Braidwood Unit 2.

Based on the above, Commonwealth Edison Company (Edison) hereby requests a schedular exemption from the documentation requirements of 10 CFR 50.49(j). This section states:

"A record of the qualification, including documentation in e paragraph (d) of this section, must be maintained in an auditable form for the entire period during which the covered item 1s installed in the nuclear power plant or is stored for future use to permit verification that each item of electric equipment important to safety covered by this section:

i (1) Is qualified for its application; and f

l (2) Meets its specified performance requirements when it is subjected to the conditions predicted to be present when it must perform its safety function up to the end of its qualified life."

f In order to be granted an exemption from RRC regulations, the requirements of 10CFR 50.12 must be met.

10 CFR 50.12(a) states:

"The Commission may . . . grant exemptions from the requirements of the regulations of this part, which are -

(1) Authorized by law, will not present an undue risk to the public health and safety, and ere consistent with the common defense and security."

The exemption being requested is authorized by law. It is clearly within the Commission's authority to grant an exemption to the provisions of 10 CFR 50.49(j). There will be no adverse effects on the common defense and security. Further, the granting of t..a schedular exemption will present no undue risk to public health and safety.

Section 50.12(a)(2) identifies six categories of special circumstances, one or more of which must be present for the Commission to consider granting an exemption. Two of these categories, (iii), and (v),

apply to this request and are discussed below:

(iii) Compliance would result in undue hardship or other costs that are significant1v in_ excess of those contemplated when the regulation was adopted, or that are significant1Y in excess of those incurred bY others similarly situated:

l l Edison fully intended to meet 10 CFR50.49 concerning this one penetration item. The significance of the need for additional supporting documentation does not rule out that the penetration is fully environmentally qualified. References (a) and (b) provide the basis for this. Also, Appendix "A" provides an evaluation performed that shows that Braidwood Unit 2 can operate safely while this concern exists without endangering the health and safety of the public. Restricting the issuance of the Braidwood Unit 2 full power license based on this concern would result in other costs that are significantly in excess of those incurred by others similarly situated; such as an operating unit previously licensed which identifies a similar problem; performs a justification for continued operation; and continues operating based on that justification. Many examples of this type exist in the nuclear industry. In this case, tho documented justification for continued operation for Braidwood Unit 2 does provide such a basis.

(v) The exemption would provide only temporary relief _from the applicable regulation and the licensee or applicant has made good

. faith efforts to comp 1Y with the regulationi Edison believes that a good faith effort has been made to provide documentation that supports full environmental qualification of the penetration to 10 CFP 50.49. Upon identification of this concern, a significant effort has been made by Edison and its consultants to resolve ,

this issue. Key members of the NRC staff are aware of these actions and the efforts that have been made. Edison is providing this exemption request to 10 CFR 50 49(j) so that Edison may pursue the resolution of this issue in an orderly and timely manner, and not delay the issuance of the Braidwood Unit 2 Full powec License.

Giving us assurance that this matter car be corrected is that which is presented in the NRC Staff's Safety Evaluation Report (SER) dated July 23, 1983, and subsequently reiterated in Byron SER Supplement (SSER) #5, dated October, 1984. Included in Appendix "C" to both documents is a listing of equipment that was found to be acceptable following completion of reviews by the NRC staff during or following the NRC Environmental Qualification Audit performed in Sune, 1983 at Byron Station. .ncluded in that list is this 9unker Ramo penetration.

Section 3.11.4.1.3 of the SSER states that, "items identified in Appendix C have been determined to be acceptable, pending implementation of the maintenance / surveillance program." The Bunker Ramo penetration is listed in Appendix C. In addition, on page 3-36 of the SSER, the Staff discussed Marathon 1600 terminal blocks, noting that IR values were probably too high for instrument application. The SSER acknowledges that Edison's solution was to replace all terminal blocks used in instrumentation applications with splices. This includes the Bunker Ramo penetrations now of concern. The SSER is being read as establishing a NRC Staff position that resolution of the Bunker Ramo IR problem by use of splices was acceptable. The SSER does not make any mention of a perceived need for additional testing or analysis concerning the environmental qualification of the Bunker Ramo penetration.

If, the above efforts presented do not prove to be successful, Edison will replace this penetration assembly at the four locations indicated above with a penetration assembly fully qualified to 10 CFR 50.49. Edison will schedule this work so that it can be completed prior to start-up following the first refueling outage of Braidwood Unit 2. The first refueling outage is scheduled for the third quarter of 1990.

In conclusion, Commonwealth Edison Company requests a schedular exemption from the requirements of 10CFR 50.49(j) so that the NRC staff's concerns with the environmental qualification of the Bunker-Ramo penetration do not delay the granting the Braidwood Unit 2 Full power License. Edison is continuing to work with the NRC staff concerning this issue. If, prior to Fuel Power Licensing, environmental qualification acceptance of the Bunker Ramo penetration assembly is obtained from the NRC staff, this request for exemption will no longer be necessary.

please address any questions concerning this matter to this office.

Very truly yours,

{- 4**f S. C. Hunsader Nuclear Licensing Administrator

/klj 4347K

App;ndix A SAFETY EVALUATION SAFETY FUNCTION OF INSTRUMENTATION PENETRATION ASSEMBLIES The insttumentation penetration assemblies are designed to carry the electrical l

I cignals from instrumentation inside the containment to main control room indicators and protcctive circuitry, while maintaining the integrity of the containment pressure boundary. The potential deficiency in the environmental qualification of the electrical psnstration assemblies has no effect on the pressure-retaining capabilities of the cs::mblies, but could potentially affect the electrical signals transmitted. The sp;cific instruments involved, Attachment A, provide certain inputs to the reactor protection system and engineered safety features actuation system. They also provide esrtain post-accident monitoring functions. Some of these functions are required to zitigate a LOCA, main feedwater line break, and a main steam line break. These are the cecidents that produce the hatsh environment the penetrations must withstand.

ACCOMPLISHMENT OF SAFETY FUNCTION BY OTHER EOUIPMENT A review was conducted of the FSAR accident analyses for LOCA, Main Steam line broik, and Feedwater line break, to determine the instrument channels relied upon to initiate ihe necessary projective actions in the reactor protection and engineered scfety features systems. The results of this review indicated that in all cases the containment pressure and/or steam line pressure instrument channels were available to tecomplish the required safety function. These instruments are located outside containment and would not be affected by the accidents which produce the harsh cnvironment at the electrical penetration in question. The results of the review are summarized in Attachment B.

• For thm ds2ign b2:ss Eccid:nts, ona or moro instruments, for which cnvironmental qualification is unquestioned, will provide backup ESP actuations in j cpproximately the same time frame as assumed in the accident analyses for the primary l

cetuations. Therefore, even if the primary actuation does not occur as a result of the l potential EQ deficiency, there would be no significant increase in the consequences of those accidents as previously determined in the FSAR.

Smaller pipe breaks will produce a less severe environment than the generic pressure-temperature profile used to environmentally qualify equipment which is based on design basis accidents. For smaller pipe breaks, the necessary protective functions will not be required as rapidly as assumed in the FSAR analyses. The smaller the pipe break, the longer the time reactor trip can be delayed with acceptable core consequences.

In addition, operator actions to manually actuate reactor trip and safety injection would be taken on the basis of multiple available indications (e.g.,

containment temperature, containment humidity, and containment sump levels). These operator actions would help mitigate the consequences of smaller size breaks.

A review was conducted of the Emergency Operating procedures (EOP's) that are utilized for a primary or secondary line break to determine the instrument channels relied upon for operator actions. The results of this review indicated that one or more of the following conditions was met for all cases:

1) The preferred indication is qualified and is not affected by the potential qualification deficiency, or

2) A designated, qualified backup instrument is available to provide the information, or i

• 3) The procedures provide alternative actions in the event that the item of' information cannot be obtained. These actions are conservative with respect to maintaining critical safety functions (e.g., maintaining ECCS flow if termination conditions cannot be satisfied)

The results of this review are summarized in Attachment C.

The EOPs are constructed in such a way as to utilize multiple, diverse indications whenever possible. Operators are trained not to rely on a single indicator as a basis for decision making. It can be seen from Attachments A and C that all trains of a given type of display will be either affected or unaffected by the potential EQ deficiency, therefore, the operator will not be presented with conflicting information.

For example, in checking SI re-initiation criteria, all PZR level instruments could be i affected by the potential EQ deficiency, but, at the same time, all subcooling instruments would not be affected. The EOP instructs the operator to re-initiate SI if either PZR level or subcooling reaches the specified value, l

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- ATTACHMENT A LIST OF INSTRUMENTS CONNECTED THROUGH THE INSTRUMENTATION ELECTRICAL PENETRATION ASSEMBLIES PENETRATION 2SIO58 Instrument No. Parameter Measured 2TE-410A Spare 2TE-410B Spare 2TE-411A Loop 2A Hot Leg Temperature 2TE-411B Loop 2A Cold Leg Temperature 2TE-RCO22A Reactor Coolant Loop 2A Hot Leg Wide Range Temperature 2TE-RC023A Reactor Coolant ?...op 2B Hot Leg Wide Range Temperature 2TE-RC024A Reactor Coolant Loop 2C Hot Leg Wide Range Temperature 2TE-RC025% Reactor Coolant Loop 2D Hot Leg Wide Range Temperature 2FT-414 Reactor Coolant Loop 2A Flow 2FT-424 Reactor Coolant Loop 2B Flow 2FT-434 Reactor Coolant Loop 2C Flow 2FT-444 Reactor Coolant Loop 2D Flow 2FT-512 Steam Generator Loop 2A Steam Flow 2FT-522 Steam Generator Loop 2B Steam Flow 2FT-532 Steam Generator Loop 2C Steam Flow 2FT-542 Steam Generator Loop 2D Steam Flow 2LT-556 Steam Generator 2A Level 2LT-529 Steam Generator 2B Level 2LT-539 Steam Generator 2C Level 2LT-559 Steam Generator 2D Level 2PT-455 Pressurizer Pressure 2LT-459 Pressurizer Level 2LT-501 Steam Generator 2A Wide Range Level 2PT-407 Loop 2C Hot Leg Wide Range Pressure 2FT-651 Reactor Coolant Pump 2A Bearing Water Flow 2NR07E Source and Intermedicte Range Neutron Detection 2NR08E Power Range Neutron Detection Page 1 of 4

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ATTACHMENT A LIST OF INSTRUMENTS CONNECTED THROUGH THE INSTRUMENTATION ELECTRICAL PENETRATION ASSEMBLIES (Cont)

PENETRATION 2SIO6E Instrument No. Parameter Measured 2TB-420A Spare 2TE-420B Spare 2TE-421A Loop 2B Hot Leg Temperature 2TE-421B Loop 2B Cold Leg Temperature 2TE-RCO22B Reactor Coolant Loop 2A Cold Leg Wide Range Temperature 2TE-RCO23B Reactor Coolant Loop 2B Cold Leg Wide Range Temperature 2TE-RCO24B Reactor Coolant Loop 2C Cold Leg Wide Range Temperature 2TE-RCO25B Reactor Coolant Loop 2D Cold Leg Wide Range Temperature 2FT-415 Reactor Coulant Loop 2A Flow 2FT-425 Reactor Coolant Loop 2B Flow 2FT-435 Reactor Coolant Loop 2C Flow 2FT-445 Reactor Coolant Loop 2D Flow 2FT-513 Steam Generator 2A Steam Flow 2FT-523 Steam Generator 2B Steam Flow 2FT-533 Steam Generator 2C Steam Flow 2FT-543 Steam Generator 2D Steam Flow 2LT-519 Steam Generator 2A Level 2LT-557 Steam Generator 2B Level 2LT-558 Steam Generator 2C Level 2LT-549 Steam Generator 2D Level 2PT-456 Pressurizer Pressure 2LT-460 Pressurizer Level 2LT-502 Steam Generator 2B Wide Range Level 2FT-654 Reactor Coolant Pump 2B Bearing Water Flow 2NR09E Source and Intermediate Range Neutron Detection 2NR10E Power Range Neutron Detection Page 2 of 4

ATTACHMENT A LIST OF INSTRUMENT 3 CONNECTED THROLAN THE INSTRUMENTATION ELECTRICAL PENETRATION ASSEMBt.IES (Cont)

' PENETRATION 2SIO7Lt Instrument No. Parameter Measured 2TE-430A Spare 2TE-4308 Spare 2TE-431A Loop 2C Hot Leg Temperature 2TE-431B Loop 2C Cold Leg Temperature 2FT-416 Reactor Coolant Loop 2A Flow 2FT-426 Reactor Coolant Loop 2B Flow 2FT-436 Reactor Coolant Loop 2C Flow 2FT-446 Reactor Coolant Loop 2D Flow 2LT-518 Steam Generator 2A Level 2LT-528 Steam Generator 2B Level 2LT-538 Steam Generator 2C Level 2LT-548 Steam Generator 2D Level 2PT-457 Pressurizer Pressure 21.T-461 Pressurizer Level i 2LT-504 Steam Generator 2D Wide Range Level

, 2FT-657 Reactor Coolant Pump 2C Bearing Water Flow 2NR12E Power Range Neutron Detection 1

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ATTACHMENT A LIST OF INSTRUMENTS CONNECTED THRCUGH THE INSTRUMENTATION ELECTRICAL PENETRATION' ASSEMBLIES (Cont)

PENETRATION 2SIO8%

Instrument No. Parameter Mea 3ured 4

2TE-440A Spare 2TE-440B Spare 2TE-441A Loop 2D Hot Leg Temperature 2TE-441B Loop 2D Cold Leg Temperature 2LT-517 Steam Generator 2A Level 2LT-527 Steam Generator 2B Level 2LT-537 Steam Generator 2C Level 2LT-547 Steam Generator 2D Level 2PT-458 Pressurizer Pressure 2LT-503 Steam Generator 2C Wide Range Level 2PT-406 Loop 2A Hot Leg Wide Range Prebsure 2FT-660 Reactor Coolant Pump 2D Bearing Water Flow 2NR14E Power Range Neutron Detection Page 4 of 4

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ATTACHMENT B Accident Analysis protective Functions k

LOCA MSLB FWLB _  ; _ _

r SI snd Rx trip on the SI and RX trip on the Rx trip on the following signals: following signals: following signals:

Low pzt. pressure

• Low steamline pressure Low SG 1evel

• Containment Hi-1 pressure Containment Hi-1 pressure OTAT

• Low Pzr. pressure

• HI pzr. preeser.4* (NOTE 1)

SI and ax trip on the followins signals:

Dont ~ainrant Hi-1 1ressure Low steam lino pres ure 9

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• Instruments that could be affected by potential EQ deficiency.

NOTE 1 Potential EQ deficiency would cause instrument to read erroneour'y high. Tt ?.s is conservative for high pzr pressure Rx trip.

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,.- t ATTACHMENT C Instrt!3ents Relied Upon for Operator Actions in the BOP's i 4 for_ Primary and Secondary Line Break Operator Actions Instrument Assessment ;

Varify RX trip Various 1,3 cnd ESF actuations Chick RCP trip criteria RCS wide range press, 1,3 (Note a.)

Chsck SI re-initiation RCS subcooling or 2,3 criteria PZR level

• Chsck SI termination RCS subcooling and (FW 3 i-' criteria flow or S/G 1evel*) and RC3 wide range press, and PZR level

• Chick CS termination Containment pressure 1,3 criteria Chick RHR trip criteria RCS wide range press. 1,3 Chtck S/G pressures Main steam press 1,3 i

Chick recirc sump level Recirc sump level 1,3 Rafill PZR PZR level

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( Chsck ECCS pump trip PZR level

• and subcooling 3 i criteria l

Main S/G haat sink S/G level

• or AFW flow 2,3

• Instruments that could be affected by potential EQ deficiency.

l Note a) The RCS wide range pressure channels that provide control board indication (403 and 405) are not affected by the potential EQ deficiency.

l l 8gsgg[9ssment li The prefeated indication is quallfied and is not affected by the potential defieTer.cy.

2) 7 Jesignased, seclified oackep instruraent is available to provide the information.

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3) The proceduta provides alternate a ttons In the event that the item of information i

cacaot be o'otained. These actions are conservative with respect to maintaining l critical safety functions (e.g,, raintaining ECCS flow if criteria to shutoff pumps canr:ot be ;onfirmed).

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