ML18068A439

Safety Evaluation Re Licensee 950523 Submittal of Rept Which Summarizes Results of USI A-46 Implementation Program, Established in Response to Suppl 1 to NRC GL 87-02 Through 10CFR50.54(f) Ltr

ML18068A439
Person / Time
Site:	Palisades
Issue date:	09/25/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML18068A440	List: ML18068A439 ML20154A965
References
REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-87-02, GL-87-2, NUDOCS 9810050060
Download: ML18068A439 (18)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ON CONSUMERS ENERGY COMPANY'S RESPONSE TO SUPPLEMENT NO. 1 TO GENERIC LETTER 87-02

• PALISADES PLANT DOCKET NO. 50-255 1..0 BACKGROUND In December 1980, the NRC designated "Seismic Qualification of Equipment in Operating Plants" as Unresolved Safety Issue (USI) A-46. The safety issue of concern was that equipment in nuclear plants for which construction permit applications had been docketed before about 1972 had not been reviewed according to the 1980-81 licensing criteria for the seismic qualification of equipment, such as Regulatory Guide 1.100 (Ref. 1), IEEE Standard

. 344-1975 (Ref. 2), and Section 3.10 of the Standard Review Plan (NUREG-0800, July 1981, Ref. 3). To address USI A-46, affected utilities formed the Seismic Qualification Utility Group (SQUG) in 1982.

The NRC staff issued Generic Letter (GL) 87-02 in February 1987 (Ref. 4) to provide guidance for the resolution of USI A-46. It concluded that the seismic adequacy of certain equipment in operating nuclear power plants should be reviewed against seismic criteria not in use when these plants were being constructed. In 1987, the SQUG, representing its member utilities, committed to develop a Generic Implementation Procedure (GIP) for the resolution of USI A-46.

The SQUG requested a deferment of GL 87-02's 60-day response period until after the NRC issued its final safety evaluation report (SER) on the final version of the GIP.

On May 22, 1992, the staff issued Supplement No. 1 to GL 87-02 which transmitted its final SER (SSER No. 2, Ref. 5) on the then final version of the GIP (GIP Revision 2, as corrected on February 14; 1992, or simply GIP-2, Ref. 6). *In the supplement to GL 87-02, the staff requested that USI A-46 licensees who were members of the SQUG either provide a commitment to use both the SQUG commitments and the implementation guidance described in GIP-2, as supplemented by the staffs SSER No. 2, or else provide an alternative m~thod for responding to GL 87-02. In a letter dated September 21, 1992 (Ref. 7), Consumers Power Company (CPC)1, the licensee for the Palisades Plant and. a member of the SQUG, committed to the implementation of GIP-2 for resolving USI A-46 at the Palisades Plant. The NRC subsequently approved the licensee's approach and schedule in a letter dated November 23, 1992 (Ref. 8).

1The company name was changed to Consumers Energy Company on July 21, 1997, by Amendment 176 to Facility Operating License No. DPR-20.

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'. ~ By letter dated May 23, 1995 (Ref. 9), the licensee submitted its report summarizing the results of its USI A-46 implementation program. The staff reviewed the report and issued a request for additional information(RAI) on May 31, 1996 (Ref. 10). The licensee subsequently submitted its response to the RAI in a letter dated September 27, 1996 (Ref. 11). The staff reviewed the licensee's response and determined that further information was required from the licensee in order for the staff to complete its review. A second RAI was issued to the licensee on June 19, 1997 (Ref. 12), to which the licensee responded on November 14, 1997 (Ref. 13). The staff issued an RAI regarding operator actions specified in the licensee's report in a letter dated May 12, 1998 (Ref. 18). The licensee responded to the staffs RAI in a letter dated July 8, 1998 (Ref. 19).

• This safety evaluation (SE) provides the staff's review of the licensee's.LISI A-46 implementation program. This SE is based on the staff's review of the licensee's summary report, anp supplemental information and clarification provided by the licensee in response to the staffs RAls.

2.0 DISCUSSION AND EVALUATION The staffs review of the Palisades USI A-46 summary report (Ref. 9) consisted of a screening-level review of specific sections of the licensee's program, with emphasis placed on identification and resolution of outliers, i.e., equipment items which did not readily pass GIP-2 screening and evaluation criteria. The report identifies a safe shutdown equipment list (SSEL) and contains the screening verification and walkdown of mechanical and electrical equipment.

The report also contains relay evaluations and the evaluation of seismic adequacy of tanks and heat exchangers, cable and conduit raceways, and the identification and resolution of outliers, including the proposed resolution schedules.

2.1 Seismic Demand Determination (Ground Spectra and In-structure Response Spectra)

The licen~ee stated in Section 3.1 of the Seismic Evaluation Report, contained in Reference 9, that the Palisades original seismic design is based on the Housner ground spectrum.. The safe shutdown earthquake (SSE) input motions (time history) used to perform the earthquake analysis are based on the Taft earthquake S69E recorded in 1952. For the analysis of the category I structures, the horizontal input motion is the Housner ground spectrum scaled to 0.20g peak ground acceleration (PGA). The vertical response spectra are taken as two-thirds of the horizonal free field spectrum for all plant elevations. The criteria and the procedure of in-structure response spectra (IRS) generation are described in Section 3.4 of the report. The IRS so generated are the licensing basis spectra and are the same spectra referenced in the licensee's 120-day response submitted to the NRC dated September 21, 1992 (Ref. 7). In generating the IRS for the reactor building and the auxiliary building, the ground motion spectrum defined at the plant grade level was applied at the base of the foundation to simplify the analysis. The seismic input motions and the method of developing the IRS were evaluated and approved by the staff, as documented in Reference 8. The staff finds that the licensee's approach for determining equipment seismic demand for the USI A-46 program is consistent with GIP-2 and the staffs previously approved IRS and is, therefore, acceptable.

I 2.2 Seismic Evaluation Personnel The screening verification, walkdown, and outlier identification were performed by a Seismic Review Team (SRT) comprised of Seismic Capability Engineers as defined in GIP-2. GIP-2 describes the responsibilities and qualifications of the individuals who will implement this generic procedure. For a complete resolution of the USI A-46 issue, the seismic evaluation personnel should include individuals with sufficient expertise to identify safe shutdown equipment, perform the plant walkdown, and verify the seismic adequacy of equipment and cable/conduit raceway systems, and to perform the relay screening and evaluation. This involves a number of plant and engineering disciplines including structural, mechanical, electrical, system, earthquake, and plant operatiqns. Based on the information provided in Appendix C to the Seismic Evaluation Report, the staff concludes that the qualifications of the

. individuals responsible for implementing the resolution of USI A-46, including the third party reviewers, meet the criteria of GIP-2 and the staff's SSER No. 2~ and are, therefore, acceptable.

2.3 Safe Shutdown Path GL 87-02 specifies that the licensee should be able to bring the plant to a hot shutdown condition and maintain it in this state for the first 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following an SSE. To meet this provision, in its submittal of May 23, 1995 (Ref. 9), the licensee accounted for the following plant safety functions: reactor reactivity control, pressure control, inventory control, and decay heat removal. Primary and alternate safe shutdown success paths with their support systems and instrumentation were identified for each of these safety functions to ensure that the plant is capable of being brought to, and maintained in, a safe shutdown condition for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following an SSE. Figures 1 through 11 in Attachment A to the Reference 9 Equipment Evaluation Report provide the safe shutdown success paths. Attachment B to the same report provides the SSEL.

The reactor decay heat removal function is accomplished by relieving steam from the steam generators (SGs) via the SG atmospheric steam dump valves and code safety valves. Makeup water to the SGs will be supplied by the auxiliary feedwater system, which takes suction from the condensate storage tank (CST) and from the service water system, once the CST has been depleted. Lake Michigan is the source for the service water system. Other nonseismic water sources that can be used for makeup to the SGs are the main condenser hot well, the demineralized water storage tank, and the primary system makeup storage tank. The operators also have the option of performing primary coolant system feed-and-bleed to accomplish decay heat removal.

The plant Operations Department reviewed the equipment listed in Attachment B of the Equipment Evaluation Report against the plant operating procedures and concluded that the plant operating procedures were adequate to establish and maintain the plant in a hot shutdown condition following a postulated SSE.

The staff concludes that the licensee's approach to achieve and maintain hot shutdown for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following a seismic event is acceptable.

e-e 2.4 Seismic Screening Verification and Walkdown of Mechanical and Electrical Eguipment The staff's evaluation focused primarily on the licensee's identification and resolution of equipment outliers, i.e., equipment items which do not comply with all of the screening guidelines provided in GIP-2. GIP-2 screening guidelines are intended to be used as a generic basis for evaluating the seismic adequacy of equipment. If an item of equipment fails to pass these generic screens, however, it may still be shown to be adequate by additional evaluations.

2.4.1 Equipment Seismic Capacity Compared to Seismic Demand The first screening guideline is the comparison of seismic capacity and seismic demand for the equipment involved. Palisades determined the seismic capacity of safe shutdown equipment using:

(1)

Earthquake experience data with capacity defined by the Bounding Spectrum; (2)

Generic seismic test data which have been compiled into Generic Equipment Ruggedness Spectra (GERS); or (3)

Equipment-specific seismic qualification data, or data from similar equipment.

The seismic demand imposed on an item of equipment depends on whether or not the ground spectrum or amplified floor response spectra were used, and how it is compared to the equipment seismic capacity data.

For Palisades plant equipment, conservative floor spectra were generally used for comparison to 1.5 times the Bounding Spectrum. To a lesser extent, for equipment with an estimated fundamental frequency greater than 8 Hz and mounted within about 40 feet above the effective grade of a structure, the ground spectrum was compared to the Bounding Spectrum. For some equipment that satisfy th~ above frequency and elevation criteria, GERS data were used for comparison to the conservative floor spectra or 2.25 times the SSE ground spectrum. Finally, newer, upgraded equipment that had been seismically qualified, in accordance with IEEE 344 Standard, 1975 Edition (Ref. 2) or later, were considered acceptable and were evaluated for seismic spatial interaction by the SRT.

For the purpose of determining equipment within 40 feet above grade, the "effective grade" for the site and/or each building was determined. The effective grade at a nuclear plant is defined as the average elevation of the ground surrounding the building along its perimeter. For Palisades, which is a soil site, the effective grade was established at 590 feet.

A few equipment items have been found to have conservative design floor response spectra exceeding 1.5 x Bounding Spectrum. This includes 480-volt motor control centers (EB-01, 02) and safety injection and refueling water (SIRW) low level switches (LS-0327, -0328, -0329,

-0330). Other equipment items, such as pressure relief valves (RV-1039, -1040), power relief isolation valves (M0-1042A, -1043A), and power-operated relief valves (PRV-1042B, -1043B) were found to have seismic demand, based on 2 percent of critical damping, exceeding 1.5 x

e Bounding Spectrum in the 2 Hz and 7 Hz regions of the spectrum by a significant amount.

These equipment items were identified as outliers in Table 8-1 of the Seismic Evaluation Report. As indicated in Table 9-1, the licensee proposed to resolve the outliers by reevaluating the affected equipment using seismic demand developed by employing a soil-structure interaction analysis with Regulatory Guide 1.60 ("Design Response Spectra for Seismic Design of Nuclear Power Plants") spectra as input.

In general, the staff finds the licensee's approach for evaluation of equipment seismic capacity against seismic demand reasonable and acceptable.

2.4.2 Assessment of Equipment Caveats As a second screening guideline, the licensee verified the seismic adequacy of an item of mechanical or electrical equipment by confirming that (1) the equipment characteristics are generally similar to the earthquake experience equipment class or the generic seismic testing equipment class, and (2) the equipment meets the intent of the specific caveats for the equipment class.. This review is necessary only when the Bounding Spectrum or the GERS is used to represent the seismic capacity of equipment. If equipment-specific seismic qualification data is used instead, then only the specific restrictions applicable to that equipment-specific qualification data need be applied.

The "caveats" are defined as a set of inclusion and exclusion rules, which are established to represent specific characteristics and features particularly important for seismic adequacy of a particular class of equipment. Appendix B of GIP-2 contains a summary of the caveats for the earthquake experience equipment class and for the generic seismic testing equipment class.

Another aspect of verifying the seismic adequacy of equipment included within the scope of this procedure is explained by the "rule of the box." For the equipment included in either the earthquake or testing equipment class, all of the components mounted on or inside this equipment are considered to be part of that equipment and do not have to be evaluated separately. However, the licensee stated in its submittal (Ref. 9) that the walkdown engineers have looked for suspicious details or uncommon situations that could make the equipment item vulnerable.

Only a few equipment items were found to have their characteristics outside the bound of the above defined caveats. This includes the suspected use of leaded Cinch anchors which are an anchorage type not covered in GIP-2. For service water pumps (P-7A, -7B, -7C), the length of the cantilever impeller shafts (approximately 37 feet) are found to be longer than the criteria length of 20 feet specified by GIP-2. The licensee has identified these equipment items as outliers in Table 8-1 of the Seismic Evaluation Report.

When evaluating an item of equipment, engineering judgment was often used to determine whether the specific seismic concern addressed by the caveat was met. Each item of equipment has been evaluated to determine whether it meets the specific wording of the applicable caveats or their intent. If an item of equipment was judged to have met the intent, but not the specific wording of the caveats, that item would still be considered to have met the caveat.

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• At Palisades, very few interpretations were relied upon in situations where the intent of GIP-2 caveats was used. Those interpretations or measures taken to meet the intent of the caveat are provided by the licensee in Table 5-1 of the Seismic Evaluation Report. The staff has reviewed the information provided in the table and found the SRT's interpretations and measures to meet the intent of GIP-2 caveats acceptable.

2.4.3 Equipment Anchorages As a third screening guideline, the licensee described in Section 4.1.3 of the Seismic Evaluation

_ Report the procedure used for verifying the seismic adequacy of equipment anchorages. The seismic adequacy of equipment anchorages at Palisades was evaluated by following the four main steps provided in Section 4.4 of GIP-2. As a first step, all accessible anchorages were visually inspected by taking into consideration the 14 attributes delineated in Section 4.4.1 of GIP-2. The licensee stated that the possibility of the use of leaded shell (or "ring") expansion anchors manufactured by Cinch Company was discovered. A number of anchorage installations were found not to have an identifiable manufacturer or anchor type. All these suspected anchors are considered as Cinch anchors and have been declared as outliers, according to Appendix C.2.2 of GIP-2. Before their final resolution, Cinch anchors are required to be checked for tightness to ensure that they are still viable (not loose) in their installation.

For expansion anchors, a tightness check is required to detect gross installation defects that would result in the anchor being loose in the hole. The licensee has established a criterion and method of tightness check that is considered reasonable. The tightness check will be scheduled for a subsequent refueling outage. The licensee provided a list of equipment anchorages to be checked by the tightness check process, including those with suspected Cinch anchorages, as shown in Table 4-1 of the Seismic Evaluation Report.

The second step in evaluating the seismic adequacy of equipment anchorages was to determine the allowable capacity of the anchors. The allowable capacity is obtained by multiplying the nominal allowable capacities by the applicable capacity reduction factors. The nominal allowable capacities and reduction factors were obtained from Appendix C of GIP-2 and determined from the results of the anchorage installation inspection checks. The nominal allowable capacity of an anchor consists of the nominal pullout capacity and/or the nominal shear capacity. The pullout and shear capacities are determined on the assumption that there is adequate stiffness in the base of the equipment and that no significant prying action is applied to the anchor. Otherwise, the allowable capacity loads will be reduced or the affected bolt is completely discounted.

The third step of the anchorage evaluation was to determine the seismic demand imposed on the equipment, which depends on the type of demand spectrum used. The licensee followed the recommendations contained in C.1 of GIP-2 for determining the seismic demand.

The fourth step is to compare the seismic demand to the anchorage capacity. If the demand is less than the capacity, then the anchorage is acceptable; otherwise, the equipment is declared to be an outlier.

• The staff finds *that the licensee, by following GIP-2 procedures, has established a viable program to verify the adequacy of equipment anchorages. A number of equipment anchorages that could not pass the above screening criteria were identified as outliers in Table 8-1 of the Seismic Evaluation Report. These outliers remain to be resolved by the licensee. As a whole, the staff finds the equipment anchorage evaluation acceptable for the. resolution of USI A-46.

2.4.4 Seismic Spatial Interaction Evaluation As a part of the screening provision for verifying the seismic adequacy of an item of mechanical or electrical equipment, the licensee addressed potential spatial interaction effects for the equipment in Section 4.1.4 of the Seismic Evaluation Report. This serves to ensure that there is no adverse seismic spatial interaction between the equipment under consideration and nearby equipment, systems, and structures that could cause the equipment to fail to perform its intended safe shutdown function. The interactions of concern are (1) proximity effects, (2) structural failure and falling, and (3) flexibility of attached lines and cables. Guidelines for judging potential interaction effects, when verifying the seismic adequacy of equipment, are presented in Appendix D of GIP-2.

During the plant walkdowns at Palisades, the SRT identified a few interaction concerns that were considered a personnel hazard only. For example, portable equipment items, such as carts, racks, etc., were found in the main control room, and aluminum diffusers were found at a suspended ceiling of the main control room. In. addition, overhead piping systems and ductwork were closely examined in all plant areas containing USI A-46 equipment. The SRT identified no -

vulnerabilities from these interactions and noted that the systems were well supported.

Interaction concerns that were iqentified to be of a significant nature are included in Table 8-1 of the Seismic Evaluation Report. Their proposed resolutions, as provided in Table 9-1, were reviewed and found to be reasonable.

2.5 Tanks and Heat Exchangers Section 6.1 of the Seismic Evaluation Report contains the guidelines provided in Section 7.2 of GIP-2 for the evaluation of tanks and heat exchangers. The 19 items listed in Table 6-1 were grouped as follows: two vertical flat bottom tanks, four tanks on legs, five vertical floor or wall-mounted tanks and heat exchangers, and eight horizontal tanks and heat exchangers. In Reference 11, the licensee further stated that of the above 19 tanks and heat exchangers, 12 were declared outliers that needed to be reevaluated. The licensee stated, in Reference 9, that the two flat-bottom tanks, T-58 and T-2 (safety injection and refueling water tank (SIRWT) and CST), were analyzed using the seismic margin methodology described in EPRI Report NP-6041-SL (Ref. 16). The staff questioned the validity of this methodology for the USI A-46 resolution, in Reference 10, since it was developed to determine margins for conditions beyond the design basis which may be less conservative than those obtained following GIP-2. Item T-2 has since been reevaluated by using the method in Section 7 of GIP"."2 and was determined to satisfy GIP-2 criteria. Item T-58 remains to be resolved with other outliers before the end of the second refueling outage following receipt of this SE, as indicated by the licensee in References 11 and 13.

• Vertical tanks supported on skirts or legs, which are not specifically covered by the guidelines in Section 7 of GIP-2, were evaluated using an approach similar to that described in Section 7 of GIP-2. The results from the evaluation indicate that for two tanks (T-53 A&B) the anchorages are inadequate. Therefore, these two tanks were considered to be outliers.

The licensee evaluated the horizontal tanks according to the guidelines in Section 7 of GIP-2.

The two horizontal tanks, T-13 A and B (diesel jacket water expansion tanks), were found to be outliers due to inadequate anchorage and strap restraints and remain to be resolved.

In summary, tanks T-58, T-53 A&B, and T-13 A&B are outliers that are required to be resolved for completion of the USI A-46 implementation program.

2.6 Cable and Conduit Raceways The licensee stated in Section 7 of the Seismic Evaluation Report that essentially all *electrical raceway systems were walked down by the Seismic Capability Engineers and were evaluated against the inclusion rules and the caveats. No missing or damaged hardware was identified in the scope of the walkdown. The licensee selected 12 raceway supports for Limited Analytical Review (LAR) and determined that 9 supports were adequate and 3 were outliers. The three outliers have been resolved analytically. Therefore,*the staff considers the cable and conduit raceway evaluations acceptable for the resolution of USI A-46.

2. 7 Essential Relays A review of relays associated with safe shutdown equipment is required as part of the resolution of USI A-46 program. The purpose of the relay review is to verify that safe shutdown systems would not be prevented from performing their safe shutdown functions because of relay (contact) chatter during the period of strong ground motion associated with an SSE.

2. 7.1 Essential RelaY,s The licensee's summary report (Ref. 9) indicated that the SRT relay review was conducted utilizing data obtained from the SSEL which contained a list of electrically operated USI A-46 components that require relay reviews. The list is defined as the safe shutdown relay review list (SSRL) and is a subset of the SSEL. It includes equipment that must change position or start in order to perform a safe shutdown function, as well as equipment whose inadvertent actuation due to contact chatter may compromise a safe shutdown function or provide misleading indications in the control room.

The SRT performed the relay screening for the associated relays on the SSRL, based on the following steps: (1) identified contacts that are inherently rugged or solid state that are considered not vulnerable to contact chatter (such as the mechanically actuated limit and torque switches on motor-operated valves), and excluded them from the SSRL; (2) reduced the SSRL to a list of essential relays through the elimination of relays that could be verified to not perform a function required for safe shutdown or relays whose failure would not challenge the safe shutdown process for Palisades; (3) identified the normal and required states of the essential relays, as compared to those required for a safe shutdown, using the associated

• electrical schematics; (4) screened those relays whose contact chatter is acceptable, i.e., relays whose chatter does not result in an unacceptable consequence or prevent the affected system from carrying out its required function; and (5) determined if operator action is an acceptable way of screening out certain relays, and described what operator action was needed.

The summary report (Ref. 9) also indicated that the SRT identified the manufacturer, type, and model number of the essential relays, and compared them with the list identified in Appendix E of EPRI NP-7148-SL (Ref. 14), to determine if there are any seismically sensitive relays ("Bad Actors").

The SRT used the list of essential relays and associated data, identified in the above process, to compare the capacity of the relays to their seismic demand. Of the total of 1714 essential relays, the SRT identified 1 relay as requiring operator actions, and 17 relays (8 types) as requiring corrective actions.

2.7.2 Operator Actions Required The summary report indicated that breaker 152-102 is the alternate feed for the pressurizer heater transformer #15. This alternate feed is accomplished by requiring an operator action to physically remove and relocate links in the rear of breaker cubical 152-102, and open and isolate breaker 152-305 and the associated protective devices (i.e., relay, amp meter) of breaker 152-305. In addition, operator action is also required to physically connect the cabling in accordance with the pertinent plant operating procedure.

2.1.3 Corrective Actions Required The summary report identified the following relays as outliers. The proposed resolution approaches involved an evaluation of the system operation and replacing the relays, if necessary.

(1)

Relays 1270-2 and 1270-1, Westinghouse type SV EPRI NP-7148-SL, December 1990, Appendix E, identifies these relays as low

• ruggedness relays for all modes of operation.

(2)

Relays G1-1/DR and G1-2/DR, Square D-P04 Type, Class 7001 (3)

No GERS exist for these relays in EPRI NP-7147-SL, August 1991 (Proprietary information. Not publicly available.). MPR Associates (MPR) verified that no testing had been performed on this relay type.

Relays G1-1/K1, G1-1/K1A, G1-2/K1, G1-2/K1A, Westinghouse type MD-101 No GERS exist for these relays in EPRI NP-7147-SL, August 1991. MPR verified that no testing had been performed on this relay type.

• (4)

Relays G1-1/K.2 and G1-2/K.2, Westinghouse type MD-110 No GERS exist for these relays in EPRI NP-7147-SL, August 1991. MPR verified that no testing had been performed on this relay type.

(5)

Relays 194-108, 194-211, Clark Control/Allis Chalmers These relays could not be identified. They appear to be assembled with different parts.

(6)

Relay 152-305, Allis Chalmers type MA-250C When the pressurizer heater (transformer #15) is fed from 1 C bus (A 11 }, the breaker 152-305 will be isolated. Bus 1 E was not seismically qualified.

(7)

Relays 187D-107/X, Y, Z, 187D-213/X, Y, Z, General Electric type IJD52A The GERS-RLY-PP1.5 requires that IJD relays have "HIGH-G" letters on the faceplate.

During the walkdown, the SRT was unable to verify the "HIGH-G" lettering even though the documentation for the purchase and installation reflects the appropriate requirements.

(8)

Relays 162-107X, 162-213X, Westinghouse type SG These relays are deenergized, normally closed contact. EPRI NP-7148-SL, December 1990, Appendix E, identifies these relays as low ruggedness relay for this mode of operation.

Based on its review, the staff determined that the licensee's proposed corrective actions to resolve the above identified relay outliers are acceptable. The licensee will confirm the completion of the proposed actions in a letter to the NRC.

2.8 Human Factors Aspects As part of the resolution to USI A-46, the SQUG developed GIP-2 for use in part by licensees to identify and verify a safe shutdown equipment list (SSEL) and ensure adequate procedures and training were in place for plant operators to mitigate the consequences of an SSE.

GIP-2 described the use of operator action as a means of accomplishing those activities required to achieve safe shutdown. _Section 3.2.7, "Operator Action Permitted," states, in part, that timely operator action is permitted as a means of achieving and maintaining a safe shutdown condition provided procedures are available and the op~rators are trained in their use. Additionally, Section 3.2.6, "Single Equipment Failure," states that manual operator action of equipment which is normally power operated is permitted as a backup operation provided that sufficient manpower, time, and procedures are available. Section 3.2.8, "Procedures,"

states, in part, that procedures should be in place for operating the selected equipment for safe shutdown and operators should be trained in their use. It is not necessary to develop new procedures specifically for compliance with the USI A-46 program.

• In Section 3.7, "Operations Department Review of SSEL," of GIP-2, the SQUG also described three methods for accomplishing the operations department reviews of the SSEL against the plant operating procedures. Licensees were to decide which method or combination of methods were to be used for their plant-specific reviews. These methods included:

1.

A "desk-top" review of applicable normal and emergency operating procedures,

2.

use of a simulator to model the expected transient,

3.

performance of a limited control room and local in-plant walk-down of actions required by plant procedures.

The staff's evaluation of the SQUG approach for the identification and evaluation of the SSEL, including the use of operator actions, was provided in Section 11.3 of the staff's SSER on GIP-2 (Ref. 5). The evaluation concluded that the SQUG approach was acceptable.

The staff's review of the licensee's Seismic Evaluation Report focused on verifying that the licensee had used one or more of the GIP-2 methods for conducting the operations department review of the SSEL, and had considered aspects of human performance in determining what operator actions could be used to achieve and maintain safe shutdown (e.g., resetting relays, manual operation of plant equipment).

The licensee provided information that outlined the use of the "desk-top" review method by the Operations Department to verify that existing normal, abnormal, and emergency operating procedures were adequate to mitigate the postulated transient and that operators could place and maintain the plant in a safe shutdown condition. The staff verified that the licensee had considered its operator training programs and verified that its training was sufficient to ensure that those actions specified in the procedures could be accomplished by the operating crews.

In addition the staff requested verification that the licensee had adequately evaluated potential challenges to operators, such as lost or diminished lighting, harsh environmental conditions, potential for damaged equipment interfering with the operators tasks, and the potential for placing an operator in unfamiliar or inhospitable surroundings. The licensee provided information regarding its reviews to substantiate that operator actions could be accomplished in a time frame required to mitigate the transient. Specifically, the licensee provided assurance that ample time existed for operators to take the required actions to safely shut down the plant.

This had been accomplished during validation of the pertinent plant operating procedures prior to implementation of the A-46 program. The licensee stated that no procedural changes were made as a result of the A-46 review, and since these plant procedures had already been validated to ensure that adequate time and resources are available for the operators to respond to a loss of offsite power incident it was not deemed necessary to re-validate these procedures for the USI A-46 program. The licensee verified that existing procedures, availability of lighting equipment, and operator training were adequate to ensure the operators could perform the required actions credited in the submittal.

The licensee explicitly evaluated the potential for local failure of architectural features (such as ceiling tiles in the control room) and the potential for adverse spacial interactions in the vicinity of safe shutdown equipment, where local operator action may be required, as part of the GIP-2 process. As a result of the review several seismic housekeeping issues affecting the control room were noted and resolved. Th.e one remaining issue (i.e., modification of aluminum lighting diffusers in the suspended ceiling) will be completed by the second refueling outage following receipt of this SE. Furthermore, the licensee performed seismic interaction reviews which eliminated any concerns with the plant components and structures located in the immediate vicinity of the components that had to be manipulated. Therefore the potential for physical barriers resulting from equipment or structural earthquake damage that could inhibit operator ability to access plant equipment was considered and eliminated as a potential barrier to successful operator performance.

The staff has completed its review of the human factors aspects of the licensee's submittal regarding the verification of seismic adequacy of mechanical and electrical equipment in operating reactors. The licensee has provided the staff with sufficient information to demonstrate conformance with the NRG-approved review methodology outlined in GIP-2.

2.9 Outlier Identification and Resolution As stated previously, an outlier is defined as an item of equipment that does not meet GIP-2 screening guidelines. An outlier may be shown to be adequate for seismic loadings by performing an additional evaluation using alternate methods or seismic qualification techniques acceptable to the staff. Based on the screening criteria stated in Section 2.4, a number of equipment items were identified during the walkdowns by the SRT as outliers (Table 8-1 of Ref. 9). The licensee stated that out of the 514 mechanical and electrical equipment items examined and evaluated following the walkdown, 64 were identified as outliers.

One generic issue identified during the walkdowns that may affect USI A-46 equipment items in several plant areas pertains to the possible use of leaded Cinch anchors. For the resolution of the Cinch anchors, the licensee proposed to establish conservative load allowables using the testing data from an extensive testing program undertaken at the Savannah River Site (Ref. 15). By using such data, the licensee's analysis shows the anchorages to be adequate pending bolt tightness checks.

In Table 9-1 of the report (Ref. 9), the licensee documented the resolution status for each of the equipment outliers, as either complete, in-progress, or pending with an estimated completion schedule for the proposed approach. In an RAI on May 31, 1996 (Ref. 10), the staff questioned the effectiveness of the licensee's proposed resolution for an outlier related to the lack of longitudinal restraints for Jacket Water Surge Tanks T-13A and T-13B. Specifically, the staff questioned the tightening of the U-bolts on the wall brackets of the tanks as a way of resolving the outliers. In its September 27, 1996, submittal (Ref. 11 ), the licensee responded by indicating that this would be further considered in the outlier resolution. An area also indicated by the licensee as requiring further consideration is the flexibility of the attached piping due to the fixed-end elasto-plastic deformation allowed at the brackets near the top bolt. The licensee has committed to check the flexibility of the piping connected to the diesel generator to determine if it can accommodate the displacement demand. The licensee will also perform an engineering evaluation to determine the magnitude of tension in the U-bolts in order to demonstrate that the resulting shear frictional resistance is sufficient for the seismic demand.

l

.. The staff also noted, in Table 9-1, an outlier identified for service water pumps P-7A, P7-B, and P-7C. The cantilever impeller shaft for each of the pumps is 37-feet long, which exceeds the GIP-2 caveat of 20 feet. The effects resulting from this exceedance were not addressed by the licensee in its submittal of May 23, 1995 (Ref. 9). In its September 27, 1996, submittal (Ref.

11 ), in response to the staff's RAI of May 31, 1996 (Ref. 10), the licensee stated that the pump casings are supported by two braces at elevation 583 feet. The shaft is also horizontally supported internally by rubber bearings approximately every 5 feet on center. The licensee has committed to resolve the outlier by performing an analysis to check the casing and shaft stresses, and the bearing loads due to seismic inertial effects, against their allowables. This approach is acceptable to the staff.

As stated previously, for a total of 1714 essential relays that were identified, 1 relay was identified as requiring operator action, and 17 relays (8 types) were identified to require corrective action. The licensee has committed to resolve these 17 relay outliers by system evaluation and by replacement if warranted.

Upon staff request in its RAI of May 31, 1996 (Ref. 10), the licensee included in its submittal of September 27, 1996 (Ref. 11 ), a copy of the peer review letter (Ref. Stevenson & Associates 92C2750-LSC-105, dated June 22, 1995) for the resolution of the Palisades USI A-46 Program.

The peer reviewers (i.e., the third party auditors) stated that their independent walkdowns were conducted before they reviewed the Palisades' Screening Evaluation Worksheets (SEWS) and other evaluation documentation. All accessible areas of the auxiliary building were reviewed, including the control room, cable spreading room, diesel generator-switchgear rooms, and the roof where the SIRWT is located. In addition, the turbine building, intake structure, and auxiliary feedwater pump room were also visited.

As stated in the peer review letter, a sample of SEWS was reviewed by the peer reviewers after their independent walkdowns and was generally found to be in good order. A vast majority of the findings by the peer reviewers were found to have already been identified and documented by the SRT. The peer reviewers, therefore, judged the USI A-46 walkdown to have been generally conducted in a thorough and professional manner. During the peer review walkdowns, a number of independent observations were made by th~ peer reviewers. The staff reviewed these observations and noted that follow-up actions relating to the following issues had not been initiated by the licensee to resolve the peer reviewers' observations:

(1)

The local shear stress effect (tearing) of the steel skid underneath the steam turbine-driven feedwater pump (P-88);

(2)

Lack of spacers between fire pump batteries (ED-36 & -38 A/B C/D) and the lack of restraint for the wooden battery rack cover; (3)

A potential for impact due to proximity of the Instrument AC bus transfer switch panel (EY-50) to ED-16; (4)

A potential interaction hazard for the SIRWT due to collapse of an adjacent vent stack to the containment; and

• (5)

"Seismic housekeeping" items due to lack of restraint of carts, anchorage of tables, and similar components, as identified throughout the control room.

These issues were included in the staff's second RAI of June 19, 1997 (Ref. 12). In its November 14, 1997, submittal (Ref. 13), the licensee provided its response for each of the above observations. The licensee stated that (1) the steam-driven auxiliary feedwater pump (P-88), diesel fire pump (P-41) and associated batteries (ED-36/37 A/B C/D), AC bus transfer switch panel (EY-50), and all their associated equipment are no longer within the scope of the SQUG SSEL; (2) the potential interaction between the panels, EY-50 and ED-16, was evaluated and determined by the SRT to be acceptable based on the fact that no essential relays are located in cabinet ED-16; (3) the vent stack and its mounting have subsequently

. been evaluated (EA-POC0007899-Stack) and found to maintain structural integrity under the SSE loading; and (4) the Palisades Administrative Procedure 1.01, "Material Condition Standards and Housekeeping Responsibilities," provides administrative control for unanchored equipment in the proximity of safety-related equipment.

In regard to the use of the seismic margin assessment (SMA) methodology described in EPRI report NP-6041 (Ref. 16), the staff indicated in its RAI of May 31, 1996 (Ref. 10), that the methodology may yield analytical results that are not as conservative as those that could be obtained by following GIP-2 guidelines. Because of the uncertainty of its conservatism, the methodology has not been endorsed by the staff for the analysis of safety-related systems and components, including the resolution of mechanical, electrical, and structural component outliers in the USI A-46 program. The licensee stated in its September 27, 1996 (Ref. 11) and November 14, 1997 (Ref. 13) responses, that the SMA methodology has only been used in resolving two outliers, the CST (T-2) and the SIRW storage tank, T-58). T-2 has subsequently been reassessed using GIP-2 guidelines and was determined to satisfy GIP-2 criteria. The SIRW Tank, T-58, remains as an outlier and, as such, is being resolved by the licensee along with other outliers following GIP-2 guidelines.

The licensee stated in Reference 13 that the majority of the identified outliers were associated with lack of information concerning the specific type of equipm.ent anchorage. Some of these outliers have been resolved by performing bolt tightness checks. Others are in the process of being resolved either through additional analyses or modifications.

In its September 27, 1996, submittal (Ref. 11 ), the licensee indicated that for those outliers that have not already been resolved, the resolution will be scheduled after issuance of the staff's SE related to the licensee's implementation of GIP-2. The proposed schedule indicates that the resolution of outliers will be completed before the end of the second refueling outage following receipt of this SE. The licensee further stated in its November 14, 1997, submittal (Ref. 13),

that for the outliers that were identified as not meeting the screening criteria, the final safety

• analysis report was, in general, not specific with respect to the seismic requirements for the equipment items. Therefore, the licensee stated that the outliers were not in violation of the Palisades design basis. The licensee also stated that these outliers are not considered inoperable unless they are in violation of the existing plant licensing or design bases or other regulatory requirements. It was the judgment of the SRT that the outlier equipment items are adequate to meet the licensing-basis requirements, and, as such, no SQUG outliers are.

involved in operability and reportability determinations. On this basis, the licensee determined

'. that the resolution of these outliers is not deemed to affect safe operation of the facility. The staff finds the licensee's assertion reasonable.

3.0

SUMMARY

OF MAJOR STAFF FINDINGS Based on the staff review of References 9, 11, 13, and 19, the staff found that the licensee's USI A-46 program has, in general, followed GIP-2 guidelines, and that no programmatic or significant deviations from the guidelines were made during the USI A-46 resolution process at Palisades. The staff found that the licensee's approach for determining equipment seismic demand is consistent with GIP-2 and the staff's previously app.roved in-structure response spectra and is, therefore, acceptable. The licensee has provided a list of equipment anchorages that are scheduled for verification by the tightness check process, as discussed in Section 2.9 above.

The licensee has presented acceptable approaches for resolving all the identified outliers in Table 9-1, with the exception of the following, that would require further licensee action:

1.

The licensee should complete the analysis for the cantilever impeller shafts of service water pumps P-7A, -78, and -7C, which has a length exceeding the 20-foot criteria specified by GIP-2,. to confirm that the casing and shaft stresses, and the bearing loads due to seismic inertial effects, are within their allowables.

2.

The licensee should complete the evaluation and/or modification to demonstrate that the anchorage and the longitudinal restraints for jacket water surge tanks T-13A and T-138 are adequate.

3.

The licensee should complete the evaluation of the boric acid tanks, T-53A&B, whose anchorages were found to be inadequate.

4.

The licensee should complete the reevaluation of the safety injection and refueling water

. tank, T-58, using a methodology acceptable to the staff.

5.

The licensee should ensure that analyses/modifications or effectiveness checks of all leaded cirich anchors are complete.

4.0 CONCLUSION

S In general, the licensee conducted the USI A-46 implementation in accordance with GIP-2. The licensee's submittal on the USI A-46 implementation indicated that the SSEL contained 514 equipment items excluding heat exchangers and tanks and electrical raceways. Of this population, 48 items were classified as outliers, of which some have been resolved. Nineteen tanks and heat exchangers were evaluated, and.twelve were declared outliers, generally due to exceeding anchorage allowables. Ofthese 12 outliers, 5 (T-58, T-53 A&B, and T-13 A&B)

.remain to be resolved. The licensee also selected 12 raceway supports for Limited Analytical Review (LAR), and 3 were determined to be outliers. These three outliers have been resolved analytically. In addition, the licensee also indicated that of a total of 1714 essential relays, 17 were identified as requiring corrective actions, involving the evaluation of system operation and

• relay replacements. According to the licensee, all the above remaining unresolved outliers will be resolved by the end of the second refueling outage following receipt of this SE. The licensee's implementation program did not identify any instance where the operability of a particular system or component was questionable. The staff's review of the licensee's implementation program resulted in the identification of five findings that are described in Section 3.0 of this report. The findings represent specific areas where the licensee's program did not meet certain provisions in GIP-2 and/or the staff's SSER No. 2 on SQUG/GIP-2 issued in 1992. These areas should be resolved in conjunction with the completion of the USI A-46 implementation program.

The staff concludes that the licensee's USI A-46 implementation program has, in general, met the purpose and intent of the criteria in GIP-2 and the staff's SSER No. 2 for the resolution of USI A-46. Although there are still outlier items that are not completely resolved, the staff has determined that th.e licensee's already completed actions will result in safety enhancements that, in certain aspects, are beyond the original licensing basis. As a result, the licensee's actions provide sufficient basis to close the USI A-46 review at the facility. The staff also concludes that the licensee's implementation program to resolve USI A-46 at the facility has

• adequately addressed the purpose of the 10 CFR 50.54(f) request. Licensee activities related

. to the USI A-46 implementation may be subject to future NRC audit and inspection.

Regarding future use of GIP-2 in licensing activities, the licensee _may revise its licensing basis in accordance with the guidance in Section 1.2.3 of the staff's SSER No. 2 on SQUG/GIP-2, and the staff's letter to SQUG's Chairman, Mr. Neil Smith on June 19, 1998. The primary considerations in the licensee's determination to incorporate GIP-2 in the licensing basis are completing the resolution of outliers not yet resolved, and implementing the resolution of outliers scheduled to be completed by the end of the second refueling outage following receipt of this SE. Where plants have specific commitments in the licensing basis with respect to seismic qualification, these commitments should be carefully considered. The overall cumulative effect of the incorporation of the GIP-2 methodology, considered as a whole, should be assessed in making a determination under 10 CFR 50.59. An overall conclusion that no unreviewed safety question is involved is acceptable so long as any changes in specific commitments in the licensing basis have been thoroughly evaluated in reaching the overall conclusion. If the overall cumulative assessment leads a licensee to conclude an unreviewed safety question is involved, incorporation of the GIP-2 methodology into the licensing basis would require the licensee to seek an amendment under the provisions of 10 CFR 50.90.

5.0 REFERENCES

1.

Regulatory Guide 1.100, "Seismic Qualification of Electric and Mechanical Equipment for Nuclear Power Plants," Revision 2, 1987.

2.

IEEE Standard 344-1975, "IEEE Recommended Practices for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations," dated January 31, 1975.

3.

NRC Standard Review Plan (NUREG-0800), Section 3.10, "Seismic and Dynamic Qualification of Mechanical and Electrical Equipment," Revision 2, July 1981.

• 4.

NRC Generic Letter 87-02, "Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors, Unresolved Safety Issue (USI) A-46,"

February 19, 1987.

5.

NRC Generic Letter 87-02, Supplement No. 1, transmitting "Supplemental Safety Evaluation Report No. 2 (SSER-2) on SQUG Generic Implementation Procedure, Revision 2, as corrected February 14, 1992 (GIP-2)," May 22, 1992.

• 6.

"Generic Implementation Procedure (GIP) for Seismic Verification of Nuclear Power Plant Equipment," Revision 2, corrected February 14, 1992, Seismic Qualification Utility Group, February 1992.

7.

Letter, G.B. Slade, Consumers Power Company (CPC), to NRC Document Control Desk, "Response to Supplement 1 to Generic Letter 87-02, SQUG Resolution of USI A-46," Docket No. 50-255, dated September 21, 1992.

8.

Letter, A. Masciantonio, NRC, to G.B. Slade, CPC, "Evaluation of the Palisades Plant 120-Day Response to Supplement No. 1 to Generic Letter 87-02," Docket No. 50-255, dated November 23, 1992.

9.

Letter, K.M. Haas, CPC, to NRC Document Control Desk, "Seismic Evaluation Report Summarizing the Results of the A-46 Program Review for the Palisades Plant," Docket No. 50-255, dated May 23, 1995.

10.

Letter, R.G. Schaaf, NRC, to R.W. Smedley, CPC, "Request for Additional Information,"

Docket No. 50-255, dated May 31, 1996.

11.

Letter, T.C. Berdine, CPC, to NRC Document Control Desk, "Report of SQUG Assessment at the Palisades Plant for the Resolution of USI A-46 Submittal - Request for Additional Information," Docket No. 50-255, dated September 27, 1996.

12.

Letter, R.G. Schaaf, NRC, to T.C. Berdine, CPC, "Second Request for Additional Information," Docket No. 50-255, dated June 19, 1997.

13.

Letter, T.C. Berdine, Consumers Energy Company (CEC) to NRC Document Control Desk, "Report of SQUG Assessment at the Palisades Plant for the Resolution of USI A-46 Submittal - Response to Request for Additional Information," Docket No. 50-255, dated November 14, 1997.

14.

EPRI Report NP-7148-SL, "Procedure for Evaiuating Nuclear Power Plant Relay Seismic Functionality," dated December 1990. (Proprietary information. Not publicly available.)

15.

E.L. Bryant, Westinghouse Savannah River Company, "Lead Expansion Anchor Load Capacity in Reactor Buildings at the Savannah River Site," RTR-2661, dated August 15, 1989.

• 16.

EPRI Report NP-6041-SL, "A Methodology for Assessment of Nuclear Power Plant Seismic Margin (Revision 1);" dated August 1991.

17.

Letter, J. Stolz, NRC, to Neil Smith, SQUG, "Incorporation of the Generic Implementation Procedures into the Licensing Basis," dated November 26, 1997.

18.

Letter, R.G. Schaaf, NRC, to N. Haskell, CEC, "Request for Additional Information Regarding Consumers Energy Company's Response to NRC Generic Letter 87-02,

'Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors, Unresolved Safety Issue A-46'," Docket No. 50-255, dated May 12, 1998.

19.

Letter, N. Haskell, CEC, to NRC Document Control Desk, "Report of SQUG Assessment at the Palisades Plant for the Resolution of USI A-46 Submittal - Response to Request for Additional Information," Docket No. 50-255, dated July 8, 1998.

Principal Contributors: A. J. Lee C.P. Tan G. S. Galletti R. M. Pelton Date:

September 25, 1998