DCL-15-086, ASME Section XI Inservice Inspection Program Request for Relief PRS-3

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ASME Section XI Inservice Inspection Program Request for Relief PRS-3
ML15209A956
Person / Time
Site: Diablo Canyon  Pacific Gas & Electric icon.png
Issue date: 07/28/2015
From: Allen B
Pacific Gas & Electric Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-15-086
Download: ML15209A956 (9)
v • d • e


Text

Pacific Gas and Electric Company Barry S. Allen Diablo Canyon Power Plant Vice President, Nuclear Services Mail Code 104/6 P. 0. Box 56 Avila Beach, CA 93424 July 28, 2015 805.545.4888 Internal: 691.4888 Fax: 805.545.6445 PG&E Letter DCL-15-086 U.S. Nuclear Regulatory Commission 10 CFR 50.55a ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Power Plant Units 1 and 2 ASME Section Xllnservice Inspection Program Request for Relief PRS-3

Dear Commissioners and Staff:

Pursuant to 10 CFR 50.55a(z)(2), PaCific Gas and Electric Company (PG&E) hereby requests NRC approval of lnservice Inspection (lSI) Request for Relief PRS-3, for the Diablo Canyon Power Plant (DCPP) Units 1 and 2 third lSI interval.

The request is based on the hardship of applying the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI requirements for visual examination, VT-2 for Class 1 piping between first and second vent, drain, and test isolation devices at DCPP. The details of the request are included in the enclosure.

PG&E requests approval of PRS-3 by May 30, 2016.

This communication does not contain regulatory commitments (as defined by NEI 99-04).

If you have any questions or require additional information, please contact Mr. Hossein Hamzehee at (805) 545-4720.

Sincerely, s'!!.~n J /kL--

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

  • Diablo Canyon
  • Palo Verde
  • Wolf Creek

Document Control Desk PG&E Letter DCL-15-086 July 28, 2015 Page 2 rntt/4231/50033145 Enclosure cc: Diablo Distribution cc/enc: Marc L. Dapas, NRC Region IV Administrator John P. Reynoso, NRC Acting Senior Resident Inspector Siva P. Lingam, NRR Project Manager Gonzalo L. Perez, Branch Chief, California Department of Public Health State of California, Pressure Vessel Unit A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

  • Diablo Canyon
  • Palo Verde
  • Wolf Creek

Enclosure PG&E Letter DCL-15-086 10 CFR 50.55a Relief Request PRS-3 Class 1 piping vent, drain, and test isolation devices Proposed Alternative in Accordance with 10 CFR 50.55a(z)(2)

--Hardship or Unusual Difficulty Without a Compensating Increase in the Level of Quality and Safety--

1. ASME Code Components Affected ASME Section XI Class 1 piping system vent, drain, and test connection segments between first-off and second-off isolation valves are affected. See Tables 1 and 2 for lists and descriptions of segments for each unit.

Code Cat./ Description Part Examined Item No.

B-PI 815.10 All pressure retaining Pressure retaining components components

2. Applicable Code Edition and Addenda The Diablo Canyon Power Plant (DCPP) third lnservice Inspection Interval Program Plan (ISIPP) is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, 2001 Edition with Addenda through 2003.

The DCPP Unit 1 third inspection interval commenced on January 1, 2006, and nominally ended on May 6, 2015. The DCPP Unit 2 third inspection interval commenced on July 1, 2006, and is nominally scheduled to end on March 12, 2016. Actual end dates of the intervals are dependent on the completion dates of the 19th refueling outages for each unit, in accordance with ASME Section XI, paragraph IWA 2430(d)(1 ).

3. Applicable Code Requirement ASME Section XI requires that a system leakage test of the Class 1 pressure retaining components be completed prior to plant startup following a reactor refueling outage in accordance with the requirements of IWB-5220. Paragraph IWB 5222(a) requires the pressure retaining boundary during the system leakage test shall correspond to the reactor coolant boundary, with all valves in the position required for normal reactor operation startup. The visual examination shall extend to and include the second closed valve at the boundary extremity.

1

Enclosure PG&E Letter DCL-15-086 Paragraph IWB-5222(b) requires the pressure retaining boundary during the system leakage test conducted at or near the end of each inspection interval extend to all Class 1 pressure retaining components within the system boundary.

As an alternative to IWB-5222(b), ASME Code Case N-798 "Alternative Pressure Testing Requirements for Class 1 Piping Between the First and Second Vent, Drain, and Test Isolation Devices" states that: for portions of Class 1 vent, drain, and test piping between the first and second isolation devices that normally remain closed during plant operation, only the boundaries of IWB-5222(a) shall apply.

4. Reason for Request

The DCPP line segments between the manual isolation valves (or between the manual isolation valve and blind flange) serve as open- or closed-end vent, fill, drain, or test lines. All of the segments are short, the closed end drains less than 18 inches and the open end segments less than 12 inches on average; and small diameter, being% inch NPS, 1 inch NPS, or 2 inch NPS as listed in Tables 1 and

2. The vent, drain and test connection valves in normal alignment are closed and none of the isolation valves are capable of automatic actuation. The line segments are not normally pressurized. Line pressure may exist due to first-off valve leak by and thermal effects.

Paragraph IWB-5222(b) requires the pressure retaining boundary during the system leakage test conducted at or near the end of each inspection interval shall extend to all Class 1 pressure retaining components within the system boundary. Relief is requested for the following reasons:

a) Using system pressure to test these line segments would require opening the first-off manual valve in Mode 3 (Hot Standby) to pressurize between the two valves or valve and blind flange. However, pressure testing in this manner would result in violation of the Class 1 system requirement for double isolation valve protection.

b) For the closed end line segments, costly system modifications would be required to cut into the system and weld in test connections with open ended isolation valves at each location, and concurrent unnecessary radiation exposure to personnel, in order to permit pressurization with a hydro pump during Mode 6 (Refueling). Testing these closed end drain segments without modification would require defueling the reactor, reclosing and repressurizing the primary system with the first-off valves open, thus extending the outage critical path by approximately ten days.

Both of these options constitute extreme hardships with no compensating increase in safety.

c) For the open ended line segments, testing in Mode 6 without modification is possible because the lines are provided with test connections and 2

Enclosure PG&E Letter DCL-15-086 inboard isolation. However, pressurizing each line segment to the nominal reactor coolant system operating pressure would require use of a hydro pump at each of the locations. This would result in radiation exposure to plant personnel and increase the risk of contaminated liquid spill. All of these locations are in radiation areas. Staging the hydro pump, providing access, removing the pipe cap, opening the second off valve, filling and pressurizing the line segment, inspecting, depressurizing and restoring the system, securing the equipment, and disposing of effluent would result in radiation exposure at each location dependent upon dose rates. The dose rates at these locations may change depending on changing conditions and on-going evolutions in nearby areas. This radiation exposure would also constitute a hardship with no compensating increase in safety.

5. Proposed Alternative and Basis for Use Code required VT -2 examinations of the Class 1 system are performed each refueling outage during the system leakage test. Each line segment listed in Table 1 and Table 2 will be visually inspected during the system leakage test; however, the line segments will not be pressurized to full system pressure.

Pressure may exist due to upstream valve leak by and thermal effects.

Code Case N-798, "Alternative Pressure Testing Requirements for Class 1 Piping Between the First and Second Vent, Drain, and Test Isolation Devices" was approved by the ASME Committee on December 20, 2010. This Code Case allows the use of IWB-5222(a) for defining the pressure test boundary as an acceptable alternative to the extended pressure test boundaries of IWB-5222(b).

6. Duration of Proposed Alternative Relief is requested for the remainder of the DCPP Unit 1 and Unit 2 third inservice inspection (lSI) intervals. The DCPP Unit 1 third inspection interval nominally ended on May 6, 2015. The DCPP Unit 2 third inspection interval is nominally scheduled to end on March 12, 2016. Actual end dates of the interval are dependent on the completion dates of the 19th refueling outages for each unit, in accord with ASME Section XI, paragraph IWA-2430(d)(1).
7. Precedents This request is essentially identical to pressure test relief PRS-3, R 1 approved in an NRC letter dated October 26, 2005 for the second lSI interval. The relief request PRS-3, R1 approval also referenced PRS-3 approved in an NRC letter dated October 15, 1998. Certain vent or drain lines have subsequently been removed and capped, therefore those piping segments are not included in this request. This request adds line 6178 Reactor Pressure Vessel (RPV) Head VenU Reactor Vessel Refueling Level Indication System (RVRLIS), due to replacement of the reactor heads; Line 1140 to vacuum degas system; Line 2573 and Line 7178 Charging Injection and Safety Injection (SI) Pump Test; and Lines 3

Enclosure PG&E Letter DCL-15-086 1999, 2000, 2001, and 2002 Safety Injection System (SIS) Accumulator Test due to piping modifications. The pressurizer loop seal vent has a difference in boundary, with the previously approved inboard isolation valves now in the open position, the two boundary valves are now 8093 and 8052. The Class 2 portion of the previous interval request is no longer applicable.

This request is also similar to the following two relief requests that were approved by NRC recently:

  • NRC Letter to St. Lucie Plant, Dated November 25, 2013: Relief From the Requirements of the American Society of Mechanical Engineers Code Regarding Extension of Pressure Retaining Boundary During System Leakage Test (TAC No. MF0711).
  • NRC Letter to Sequoyah Nuclear Plant, Dated May 20, 2014: Sequoyah Nuclear Plant, Unit 1 and 2- Relief Request 11-SPT-1 for Alternative System Leakage Test (TAC Nos. MF2327 and MF2328).
8. References
1. ASME Code Case N-798 "Alternative Pressure Testing Requirements for Class 1 Piping Between the First and Second Vent, Drain, and Test Isolation Devices"Section XI, Division 1 4

Enclosure PG&E Letter DCL-15-086 Table 1: Unit 1 - Applicable Piping Segments Size Description Location Type

%in . Line 2527 RCP Loop 1 Seal lnj Drain RCDT Between valves 8364A & 283 Drain

%in. Line 2534 RCP Loop 2 Seal lnj Drain RCDT Between valves 8364B & 294 Drain

%in. Line 2536 RCP Loop 3 Seal lnj Drain RCDT Between valves 8364C & 303 Drain

%in. Line 2541 RCP Loop 4 Seal lnj Drain RCDT Between valves 8364D & 308 Drain 2 in. Line 958 RCP Loop 1 Crossover Drain Between valves 8057 A & Drain RCDT 8058A 2 in. Line 959 RCP Loop 2 Crossover Drain Between valves 8057B & Drain RCDT 8058B 2 in. Line-960 RCP Loop 3 Crossover Drain Between valves 8057C & Drain RCDT 8058C 2 in. Line 961 RCP Loop 4 Crossover Drain (to Between 8057D, 8066, & Drain

%") 8058D

%in. Pzr Spray_ (Line 13) Vent to RCDT Between valves 513 & 514 Drain

%in. Line 14 Loop 2 spray vent Between valves 517 & 518 Vent

%in. Line 14 Loop 2 spray drain to RCDT Between valves 515 & 516 Drain

%in. Line 14 Loop 2 spray drain to RCDT Between valves 519 & 520 Drain

%in. Line 13 Loop 1 spray vent Between valves 521 & 522 Vent

%in. Line 13 Loop 1 spray drain to RCDT Between valves 523 & 524 Drain

%in. Line 1195 Pressurizer PORV vent Between valve 8056 & blind Vent flange

%in. Line 1469 Pressurizer loop seal vent Between valves 8093 & 8052 Vent

%in. Line 37 48 RCP 1 seal bypass vent Between valve 8362A & blind Vent flange

%in. Line 37 49 RCP 2 seal bypass vent Between valve 8362B & blind Vent flange

%in. Line 3750 RCP 3 seal bypass vent Between valve 8362C & blind Vent flange

%in. Line 3751 RCP 4 seal bypass vent Between valve 8362D & blind Vent flange

%in. Line 235 Safety lnj loop 1 hot leg vent Between valves 50 & 51 Vent

%in. Line 237 Safety lnj loop 3 hot leg vent Between valves 58 & 59 Vent

%in. Line 109 Hot Leg recirc vent Between valves 6 & 935 Vent

%in. Line 109 Loop 4 valve 8702 thermal Between valves 3, 4 & 7 Drain expansion drain 2 in. Line 1140 to vacuum degas system Between valves 665 & 666 Test 1 in. Line 6178 RPV Head Vent! RVRLIS Between valves 8070 & 744 Vent 1 in. RPV Head Vent Between valves 8078C & Vent 8078D 1 in. RPV Head Vent Between valves 8078A & Vent 8078B 1 in. Line 7011 Vacuum Refill system connection Between valves 731 & 732 Test 1 in. *Line 2573 lnj & Sl Pump 1-1 Test Between valves 309 & 31 0 Test

%in.

  • Line 7178 lnj & Sl Pump 1-1 Test Between valves 311 & 312 Test

%in.

%in.

%in.

%in.

  • Note: These six piping segments are located between second-off and third-off isolation valves.

These segments are also designated as Class 1 by DCPP design, and will be considered the same as first and second off segments as described in the code case.

5

Enclosure PG&E Letter DCL-15-086 Table 2: Unit 2 - Applicable Piping Segments Size Location Description Type

%in. Line 2527 RCP Loop 1 Seal lnj Drain RCDT Between valves 8364A & 283 Drain

%in. Line 2534 RCP Loop 2 Seal lnj Drain RCDT Between valves 8364B & 294 Drain

%in . Line 2536 RCP Loop 3 Seal lnj Drain RCDT Between valves 8364C & 303 Drain

%in. Line 2541 RCP Loop 4 Seal lnj Drain RCDT Between valves 8364D & 308 Drain 2 in. Line 958 RCP Loop 1 Crossover Drain Between valves 8057A & Drain RCDT 8058A 2 in. Line 959 RCP Loop 2 Crossover Drain Between valves 8057B & Drain RCDT 8058B 2 in. Line-960 RCP Loop 3 Crossover Drain Between valves 8057C & Drain RCDT 8058C 2 in . Line 961 RCP Loop 4 Crossover Drain (to Between 8057D, 8066, & Drain

%11) 8058D

%in. Pzr Spray (Line 13) Vent to RCDT Between valves 513 & 514 Drain

%in. Line 14 Loop 2 spray vent Between valves 517 & 518 Vent

%in. Line 14 Loop 2 spray drain to RCDT Between valves 515 & 516 Drain

%in. Line 14 Loop 2 spray drain to RCDT Between valves 519 & 520 Drain

%in. Line 13 Loop 1 spray vent Between valves 521 & 522 Vent

%in. Line 13 Loop 1 spray drain Between valves 523 & 524 Drain

%in . Line 1195 Pressurizer PORV vent Between valve 8056 & blind Vent flange

%in. Line 1469 Pressurizer loop seal vent Between valves 8093 & 8052 Vent

%in. Line 37 48 RCP 1 seal bypass vent Between valve 8362A & bind Vent flang

%in. Line 3749 RCP 2 seal bypass vent Between valve 8362B & bind Vent flang

%in. Line 3750 RCP 3 seal bypass vent Between valve 8362C & bind Vent flang

%in . Line 3751 RCP 4 seal bypass vent Between valve 8362D & bind Vent flang

%in. Line 235 Safety I nj loop 1 hot leg vent Between valves 50 & 51 Vent

%in. Line 236 Safety I nj loop 2 hot leg vent Between valves 54 & 55 Vent

%in. Line 238 Safety lnj loop 4 hot le_g vent Between valves 62 & 63 Vent

%in. Line 109 Hot Leg Recirc Drain between valves 579 & 570 Drain

%in. Line 109 Hot Leg recirc vent Between valves 936 & 935 Vent

%in. Line 109 Loop 4 valve 8702 thermal Between valves 4, 5 & 6 Drain expansion drain 2 in. Line 1140 to vacuum degas system Between valves 684 & 685 Test 1 in. Line 6178 RPV Head Vent! RVRLIS Between valves 8070 & 744 Vent 1 in . RPV Head Vent Between valves 8078C & Vent 8078D 1 in. RPV Head Vent Between valves 8078A & Vent 8078B 1 in. Line 7011 Vacuum Refill system conn Between valves 687 & 688 Test 1 in. *Line 2573 lnj & Sl Pump 1-1 Test Between valves 309 & 31 0 Test

%in. *Line 7178 lnj & Sl Pump 1-1 Test Between valves 311 & 312 Test

%in.

%in.

%in. *Line 2001 SIS Accumulator 3 Test Between valves 301 C & 303C Test

%in.

  • Note: These six piping segments are located between second-off and third-off isolation valves.

These piping segments are also designated as Class 1 by DCPP design, and will be considered the same as first and second off segments as described in the code case.

6

Enclosure PG&E Letter DCL-15-086 The following acronyms are used in Table 1 and Table 2:

lnj injection PORV power-operated relief valve Pzr pressurizer RCDT reactor coolant drain tank RCP reactor coolant pump Recirc recirculation RPV reactor pressure vessel RVRLIS reactor vessel refueling level indication system SIPump safety injection pump SIS safety injection system 7

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