ML20073E413
| ML20073E413 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 04/15/1991 |
| From: | Helwig D PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9104300196 | |
| Download: ML20073E413 (10) | |
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PHILADELPHI A ELECTRIC COMPANY NUCLEAR GROUP HEADQUARTERS 955-65 CHESTERBROOK BLVD.
WAYNE PA 19087 5691 (als) sao.ssso April 15, 1991 D AVID R. HELWlo
.S*.5."." '.Y..' "a'... v,..
Docket Nos.
50-277 auct..
50-278 License Nos.
DPR-44 DPR-56 U.S. Nuclear Regulatory Commission Attn Document Control Desk Washington, DC 20555
SUBJECT:
Peach Bottom Atomic Power Station, Unita 2 and 3 Response to March 12, 1991 Meeting on Emergency Diesel Generators
REFERENCE:
Meeting Summary issued by G.
Y. Suh (NRC) dated March 25.-1991
Dear Sir:
The purpose of this letter is to provide the information requested by the NRC at a meeting between the NRC and Philadelphia Electric Company (PEco) held on March 12, 1991.
The subject of the meeting was the Emergency Diesel Generator (EDG) 1 loading for Peach Bottom Atomic Power Station (PBAPS), Units 2 I
and 3.
'The NRC issued a summary of.the meeting in the above referenced document.. This summary included:the Action Items to which PECo agreed at the meeting.
PEco responnes to these Action items are provided as an Enclosure to this letter.
If you. require any additional-information,. please contact us.
Very truly yours.
l f n >l k f e.n.
t-2 u e r w a <,
Enclosure cci T. T. Martin, Administrator, Region -I. - USNRC 1
J.-J. Lyash,.USNRC Senior Resident Inspector, PB 4
9104300196 910415
- pp /
DR-ADOCK 0500 7
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Enclosuro Page 1 Peach Bottom Atomic Power Station, Units 2 and 3 Response to March 12, 1991 Meeting on Emergency Diesel Generatore The Action Items agreed to by Philadelphia Electric Company (PECo) at the March 12, 1991 meeting are enumerated below in order of their appearance in the NRC Meeting Summary.
(1)
Document the current continuous and 2000-hr Emergency Diesel Generator (EDG) ratings (2)
Commit to the design basis loading profiles denoted as
" actual loads" in the meeting handouts (3)
Incorporate the " actual loads" into the nuxt Updated Final Safety Analysis Report (UFSAR)
(4)
Commit to maintain design basis loading profiles within the 2000-hr EDG ratings with one exception of the first 10 minutes for the E-2 EDG (5)
Confirm that the EDG ratings are based on an appropriate consideration of plant specific installation parameters such as ambient room temperature, combustion air temperature and cooling water temperatures (6)
Confirm with the EDG manufacturer that the EDG ratings are valid given plant specific installation parameters (7)
Provide tabulations of loading profiles (8)
Complete an ongoing reevaluation of EDG testing practices and requirements, with the submittal of an associated Technical Specifications Change Request (9)
Provide additional information on turbocharger l
effectiveness (10) Provide additional information on which component loads were based on test data and whi9h were based on calculated values The PECo responses to those items are provided below, In some instances, the Action Items have been reordered and l
closely related items have been grouped together.
1 Response to Action Item (1):
i l
The complete spectrum of ratings for each of the four EDGs is as follows:
l continuous
=
2600kW 2000-hr 3000kW
=
200-hr
=
3100kW 30-min 3250kW
=
Enclosure Page 2 Revision 8 of the Peach Bottom UFSAR (1/89) Chapter 8.5 states that the 2000-hr rating of the EDGs is 2840kW.
The response to question 8.6-2c, i ncluded in Supplement 1 of the Peach Bottom Final Safety Analysis Report (FSAR) stated that the 2000-hr rating of the EDGs is 3000kW.
Apparently, a transcription error occurred during the incorporation of the FSAR Supplement information into the UFSAR that resulted in the 2840kW value being given as the 2000-hr rating.
The actual 2000-hr rating of the EDGs is 3000kW.
This value hus been reconfirmed by letter from the EDG manufacturer, and will be reflected in the UFSAR.
In addition to providing the complete spectrum of ratings, we are providing PECo's interpretation of how the ratings were intended to be used.
This interpretation has been verified by the EDG manufacturer.
The above ratings are considered to be maximum values for the particular time duration specified.
This means that operation above 2600kW will place the unit within the 2000-hr range; operation above 3000kW will place the unit within the 200-hr range, and operation above 3100kW will place the unit into the 30-minute range.
The 2000-hr rating, the 200-hr rating and the 30-minute rating are considered to be cumulative values.
The running times in the higher ratings must be deducted from each of the total running times in the lower ratings.
The expiration of the 2000-hr, 200-hr or 30-minute running durations will require that a preventive-maintenance inspection be performed in accordance with the manufacturer's recommendations.
Expiration of the running durations does not imply a potential failure of the EDG, Response to Action Items (5) and (6):
Information associated with the plant specific EDG installation parameters will be provided in a separate submittal by May 31, 1991.
We are unable to generate a detailed comparative tabulation of these parameters at this time because the cognizant personnel are currently required to resolve the recent E-4 EDG emergent issue.
The E-4 issue is the subject of ongoing communications with the NRC.
Response to Action Item (4):
The Peach Bottom FSAR and UFSAR made no commitment to control loads on the EDGs to a specific rating.
Loads were controlled under the spectrum of diesel generator ratings for the three specific time intervals identified in the accident sequence analysis and as listed in Tables 8.5.2a through 8.5 21 of the UFSAR.
These intervals are 0-10 minutes, 10-60 minutes and greater than 60 minutes.
These intervals represent conservative design points.
The 10 minute point is significant because no operator action is credited prior to this point.
The 60 minute point is significant because it is the earliest anticipated point when shutdown cooling in the non-accident unit would be required.
In addition to controlling to a spectrum of ratings, it was assumed that the 30-minute and 200-hr ratings could be used any time during the accident mitigation sequence, provided the duration times were not exceeded (i.e., use of the 30-minute w
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Enclosuro Page 3 rating was not limited to the first 30 minutes following the accident).
As discussed in the meeting, the Revision 8 UFSAR tables do not represent a minimum set of essential. Design Basis Accident (DBA) (Loss of Coolant Accident (LOCA) with coincident Loss of Offsite Power (LOOP)) loads, but do include some discretionary loads.
Discretionary loads are those loads which may be manually disconnected from the EDGs since no credit is taken for this equipment to mitigate the consequences of the DBA.
Since prior load control was to a spectrum of ratings, and not a l
specific value, the load profiles given in Tables 8.5.2c through 8.5.21 of Revision 8 of the UFSAR permitted these loads as long as the spectrum of ratings was not exceeded.
Additionally, no credit was taken for attempting to equalize the loads among the EDGs.
In the 10-60 minute interval, Residual Heat Removal (RHR) pumps are secured and a High Pressure Service Water Pump (HPSW) pump is started in the accident unit.
The pump selection reflected in the UFSAR Revision 8 loading tables was arbitrary; more judicious selection would result in an equalization of loads among the EDGs and reduction of the maximum load on the EDGs for that case and interval.
The results of a preliminary design analysis were presented at the March 12, 1991 meeting which incorporated recent physical plant modin 'ations, recent operating procedure changes, and targeted the -
racted 2000-hr rating as a load control value.
The analysis demonstrated that with the exception of the 0-10 minute interval for the E-2 EDG, the design load profiles could be demonstrated to be within the 2000-hr rating of the EDGs. Therefore, as agreed upon in the March 12, 1990 meeting, PECo commits to controlling the essential DBA loads for the E-1 E-3 and E-4 EDGs to less than or equal to the 2000-hr rating of the EDGs (3000kW) for all load profile-intervals, and to less than or equal to the 200-hr rating of the EDGs (3100kw) for the E-2 EDG for the 0-10 minute interval and to less than or equal to the 2000-hr rating for the E-2 diesel generator for beyond 10 l
minutes.
Response to Action Item (2):
PECo interprets this Action Item to mean that we formally submit the load profiles presented at the March 12, 1991 meeting. provides the composite worst-case load profile for each of the four EDGs.
These profiles were generated by considering each of the ten possible permutations of a LOCA on either unit coincident with any one EDG unavailable or coincident with all four EDGs available.
A simultaneous LOOP was also l
assumed for all ten permutations.
These profiles are referred to l
as " composite" profiles because they represent the highest loading of each EDG for each of the three time intervals indicated for any of the ten permutations.
The profiles in are a result of a final design analysis.
Please note that the worst-case loading for the E-3 EDG in the 10-60 minute interval increased from 2116kW, which was presented at the March 12 meeting, to 2125kW.
This 9kW difference is a result of-the refinement which occurred when the preliminary design
}
Enclopure Page 4 analysis was converted to the final design analysis.
Also, the graphically presented information for time periods beyond one hour which was referred to at the March 12 meeting has not been included in Attachment I since the design basis is only for the three intervals provided in the UFSAR.
This information was discussed at the meeting to show that the load demands on the EDGs decrease with time due to diminishing system demands such as decay heat removal and battery charging.
As indicated in the legend at the bottom of Attachment 1,
the dashed line refers to the EDG loading presented in Revision 8 to the UFSAR and the solid line reflects the sum of the connected essential DBA loads.
As stated previously in response to Action Item (4), the actual DBA loadings differ from the Revision 8 UFSAR loadings because they incorporate modifications made after Revision 8, reflect current operating procedures and are targeted to the revised 2000-hr rating of 3000kW. presents the same information as but in tabular form.
The table numbers in the left column correspond to UFSAR table numbers. is a mark-up of existing UFSAR Revision 8 Table 8.5.2.
This mark-up reflects the sum of the connected essential DBA loads, and still includes some discretionary loads.
Response to Action Item (10):
The values used in the September 1989 "Diecel Generator Load Profiles and System Voltage Regulation Study" (EDO Load Study) and, therefore, UFSAR Tables 8.5.2a through 8.5.21 were obtained from the design drawings and motor test data sheets, when available.
All loads with the exception of the RHR pumps are nameplate values.
On a composite basis, this provides a conservatism since motors are applied with a horsepower capability greater than that required by the driven loads.
The RHR values were calculated using flow rates and the pump curves to derive the kW values.
Response to Action Item (3):
Revision 9 to the Peach Bottom UFSAR is presently scheduled to be submitted to the NRC on July 22, 1991.
To support this effort, a final review of the revision is already in progress.
Incorporation of the essential DBA loads, as discussed at the meeting, into the UFSAR requires extensive changes to the text and tables of Section 8.5, as well as a review and potential changes to other sections.
Accordingly, the necessary clarifications and commitments will be included in Revision 10.
As stated in response to Action Item (2), a mark-up of UFSAR Table 8.5.2 which reflects information presented at the meeting has been included as Attachment-3.
Revision 10 will include all changes made to the plant up to six months prior to its issuance.
Because of this, the load profiles to be submitted in Revision 10 may differ from those provided by this letter and from those which will be included in Revision 9.
j
Enclosure Page 5 l
Response to Action Item (7):
In addition to the load tabulations provided in, which are in response to Action Item (2), the NRC also requested that PECo submit an excerpted summary shoot from the September 1989 EDG Study.
This summary sheet is entitled 1
" Diesel Generator Load Summary Base and Adjusted Loads," and is included as Attachment 4.
When reviewing the attached summary sheet, it is important to consider jt within the context of the study of which it is a part.
The EDO Load Study summarized the results of a calculation which was subsequently revised.
The revised calculation was used to generate Tables 8.5.2 and 0.5.2c through 8.5.21 in Revision 8 of the UFSAR.
This calculation, along with our load control program, provide the as-built configuration of plant loads. Both the EDG Load Study and the tables in the UFSAR were developed in accordance with the succecs criterion of staying within the spectrum of EDG ratings as discussed in response to Action Item (4).
Differences exist between the numbers in the attached summary sheet and the Revision 8 UFSAR tables because the UFSAR tables are a refinement of the EDG Load Study, and include modifications made subsequent to the EDG Load Study.
It is also important to recognize that Attachment 4 is only a " snapshot" of the EDG loadings at the time that it was generated.
As such, PECo does not commit to providing updates to this summary sheet.
As with other calculations, a current calculation of EDG loading will be available at our Nuclear Group headquarters for NRC inspection.
The attached summary sheet is provided solely for historical purposes, as requested by the NRC.
Response to Action Item (8):
The current EDG testing and associated Technical Specifications are being reviewed.
At this time, we cannot project the submittal date of a resultant Technical Specifications Change Request (TSCR).
A commitment to a submittal date of a TSCR will be provided by May 31, 1991.
Response to Action Item (9):
The issue of the EDG turbocharger was discussed in a conference call conducted on March 20, 1991.
Representatives from NRC Region I, PEco and Fairbanks-Morse (EDG manufacturer) participated in the call.
The NRC expressed concern that DBA load profiles of the EDGs require them to pick up relatively large loads during the first few seconds of operation, and the turbocharger may not be up to speed, thereby resulting in the EDGs being unable to pick up the required load.
PECo responded that the effects of the turbocharger were considered when developing the load profiles.
The loads are added onto the'EDG incrementally such that they actually stimulate the turbochargers ability to attain rated speed.
Further, the effects of the turbocharger were incorporated into the computer model which was used in the EDG Load Study.
This assessment was confirmed by the i
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I Enclosure Page 6 Fairbanks-Morse representative who participated in the conference call.
Following this clarification, the NRC had no further questions, and no actions were required.
l 2119a. doc 1
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Attadment 1 i
E1 DIESEL GENERATOR E2 DIESEL GENERATOR COMPOSITE LOAD PROFILES COMPOSITE LOAD PROFILES sooo stoo.
l DG RATING 00 RATING seso 200 Hr 3100KW seso 200 Hr 3100KW 30 MIN 3250KW 30 MIN 3260KW f
KW KW stoo stoo seso _'
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tt e 7 Ti6 8eoo,
as00 1
T I
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10 WlN So WIN to WIN so WIN TIME - POST LOCA TIME POST LOCA E3 DIESEL GENERATOR E4 DIESEL GENERATOR COMPOSITE LOAD PROFILES
' COMPOSITE LOAD PROFILES asco asco,
i DG RATING DO RATING seso 200 Hr 3100KW sito 200 Hr 3100KW 30 MIN 3250KW 30 MIN 3260KW KW KW stoo stoo soH j
sooo
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sooo teto l
vs s l
ases afir i-esoo -
tsoo ties i
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10 WIN so WIN to WIN so Ml84 TIME - POST LOCA TIME POST LOCA r
L RATING
.. -. UFSAR REV.8
....... ACTUAL LOADS
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Attadrient 2 j
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Dieset Generator Leadings (kW) l 1
I Intervat 0 - 10 Min 10 Min - 1 Hr 1 Hr Plus Dieset E1-E2 E3 E4 El E2 E3 E4 El E2 E3 E4 Tabte 8.5.2c 2840 3053 2902 2967 2279 1442 1634 1207 2109 2101 1412 2549 i
Tabte 8.5.2d 2952 2901 2867 2244 832 2617 2305 2617 2549 Table 8.5.2e 2740 2801 2967 2780 2115 726 2610 1893 2870 i
Table 8.5.2f 2840 2952 2867 919 2449 2617 2961 2305 2560 Table 8.5.2g-2740 3052 2801 2760 991 2125 2590 2257 2706 j
Table 8.5.2h 2837 3059 2902 2970 2236 1449 1635 1211 2066 2107 1394 2554 Table 8.5.2i 2959 2902 2870 2858 833 2013 2715 2825 1946 j
Table 8.5.2j 2737 2802 2970 2737 2116 730 2567 1896 2875 Table 8.5.2k 2837 2959 2870 2286 2455 1211 2918 2312 2565 Table 8.5.21 2737 3059 2802 2109 2407 1314 2741 2264 2504 I
L i
0 - 10 Min 10 Min - 1 Hr 1 Hr Plus f
Max Per EDG El E2 E3 E4 El E2 E3 E4 El E2 E3 E4 l
"sotid-1ine" 2840 3059 2902 2970 2780 2858 2125 2617 2961 2715 2825 2875 i
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I
.a' FRAFS 113Lr e.s.2 illnn1RY O[_.LQ111Hg D r E s E L-G IH1111013_.LE2_IMIMIEC Y. B E313 31TEGUARS RMD SELEGIED MOM-SAFEGUARD E0121 Mawinum Loading of any One Diesel-Generator (RW)
Table
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Table Title 0-10 Min to Min-1 Nr levend ? Mr 8.5.2b Assign =ent of Safeguard E Selected Non-Safeguard Loads to Diesel-Generators E Emer-3 gency Buses 1 8.5.2cCh Biesel-Generator E Emergency 3sPMI 2.27g jLsPP7 p
Bus Loading. 4 Diesel-g Generators in Service 1 8.5.2dti Diesel-Generator E Emergency g
g A
Bus Loading. El Diesel-Mb 2
Generator Out of Service 2,780 3,*TC
,3W>rf 1 8.5.2etj Diesel-Generator C Emergency
, g 7
,) g-Bus Leading. E2 Diesel-of Service Generator O $
1 8.5.2ftk Diesel-Generator E Emergency 3g g
g Bus Loading. E3 Diesel-bN Generator Out of Service I 8.5.2gC1 Diesel-Generator & Emergency
},A*C 2.760 3p>MT sue toed
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MOTES 1.
The loadings are based on minimum engineered safeguard and selected non-safeguard loads for the situation of a design basis accident on one unit and an emergency shutdown of the other.
2.
All loads in the period 0-10 min are automatically arylied.
Beyond to min the major loads are manually switched.
3.
Additional non-safeguard loads may be manually myrfied as permitted by the available capacity of the diesel-generators.
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SUPERSEDED.
DitSit CENTR ATOR TOAD StMMART BASE AND ADJUSTED TOADS f
DIESEt-CEN'S DIESEt.
i EU t0ADfMG (TIME AS INDIEATEC)
AVAftA3tE CE IMIT #2 ttfA 1 (WIT #3 SH'JTDOW tMIT #2 SNUTDOW & t'utT F3 (OCA 0 - 10Mfu
>10Mtu-1HR
>1 wmt 0 - toutw M CM1w-ina
>1 Poet l
E1 8ASE 2889 22S4 2216 2846 2241 2335 i
[
Att oCS l
ADJUSTED 2544 2284 2216 2800 2241 2355
{
AVArtAstE l
E2 8ASE 3178 1531 2542 3189 1537 2336 f
l ADJUSTED 3140 1531 2542 3147 1537 2336 l
E3 BASE 2903 1634 1604 2906 1634 1607 l
ADJUSTED 2901 1634 1604 2905 1634 1607 I
{
l E4 8ASE 3055 1290 2692 3050 1291 2693 I
l ADJUSTED 3050 1290 2692 3045 1291 2693 j
DG E1 l
E2 SASE 3078 2332 2747 3059 2946 2944 j
tmAva tAetE l
ADJUSTED 3040 2332 2747 3047 2946 2944
?
l E3 BASE 2902 832 2809 2906 832 2812 l
l ADJUSTEtf
- 2901 832 2809 2905 832 2512 i
l l
E4 SASE 2955 2700 2692 2950 2092 2502 t
l A0 JUSTED 2930 2700 2692 2945 2092 2502
)
DC E2 l
E1 BASE 2789 2765 2697 2746 2722 2366 UNAVAtt A8tE l
- ADJUSTEt, 2744 27E5 2717 27D0 2742 2586 4
l E3 BASE 2802 2111 2297 2506 2115 20SS l
ADJUSTED 2801 2115 2297 2501 2115 2033 l
E4 BASE 3055 809 3013 3050 809 3014
{
l l
ADJUSTED 3050 809 3013 3049 809 3014 t
i 4
DC E3 l
E1 BASE 2839 8 74 3018 2546 3043 2975 tm AVA 1L Aat E l
ADJUSTED 2344 924 3068 2300 3093 3025 l
E2 BASE 307S 2537 2747 3039 1741 2541 ADJUSTED 3040 253T 2747 3047 1741 2541 l
E4 BASE 2955 2700 2692 2950 1290 2005 l
ADJUSTEo 2990 2700 2794 2949 1290 3007 l
I DC E4 j
E1 BASE 2789 2765 2697 2746 2114 1060 UNAVAflABtE ADJUSTED 2744 2765 2697 2700 2114 3060
{-
l E2 BASE 3178 1049 2457 3189 2465 2463 g
ADJUSTED 3140 1079 2457 3147 2495 2493 l
j l
E3 EASE 2002 2115 3099 2506 1313 2696 j
ADJUSTED 2801 2115 3099 2801 1313 26?6 1
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