Issue Date: 12/08/86 - 1 - 9900 ASME Section XI

NRC INSPECTION MANUAL DI

PART 9900: TECHNICAL GUIDANCE

ASMEXIA.TG

AMERICAN SOCIETY OF MECHANICAL ENGINEERS

ASME BOILER AND PRESSURE VESSEL CODE, SECTION XI

A. PURPOSE

To provide guidance on ASME Boiler and Pressure Vessel Code, Section

XI, as it relates to system pressure tests.

B. BACKGROUND

Region II requested NRR to provide a position regarding the

performance of system pressure tests (leakage and hydrostatic) using

nuclear heating and to provide a definition of plant startup with

regard to pressure testing. This directive provides NRR's response

to Region II's request.

C. DISCUSSION

ASME Code Section XI requires that the system leakage test be

performed prior to startup following each refueling outage (Table

IWB-2500-1, Note 5). The examination method required for this test

is visual, Type VT-2. Later additions of Section XI permit system

hydrostatic tests to be performed in lieu of the system leakage

test. The Code further states that reactor coolant shall be used

as the pressurizing medium. The Code also permits visual examination to be performed at 200F with appropriate pressure corresponding to a pressure consistent with fracture prevention for system

components that require a test temperature above 200 F.

ASME Code Section XI is incorporated by 10 CFR 50.55a in the NRC

regulations. Therefore, this is an issue concerning whether or not

regulations are being met, not just a code compliance question.

The position of NRR is that system pressure tests (leakage and

hydrostatic) are to be performed before the reactor goes critical

after a refueling outage. The system leakage test is a test to

determine if any abnormal leakage is occurring in the reactor

coolant pressure boundary after its opening and closing. The

hydrostatic test is a proof test of repairs on the reactor coolant

pressure boundary or other components. Prudence dictates that both

of these tests be performed at the lowest temperatures that are
9900 ASME Section XI - 2 - Issue Date: 12/08/86

consistent with the fracture prevention criteria for the reactor

vessel or other component so that stored energy can be minimized

during testing conditions by having the system water solid. The

temperature correction terms are provided to account for changes in

material properties when the vessel must be heated for fracture

prevention. NRR
Issue Date: 12/08/86 - 3 - 9900 ASME Section XI

does not believe that the temperature corrections are an invitation

to perform the testing at higher temperatures to minimize the test

pressures. The pressurizing medium is to be reactor coolant rather

than steam. NRR recognizes that some flashing to steam of any

potential leakage could occur when temperatures in excess of boiling

are necessary for testing. NRR believes that the Code section which

allows testing temperatures below 200F for corresponding pressures

is prudent for the visual examination in that the risk to plant

personnel is reduced and any leakage would be liquid and, therefore,

more rapidly detectable.

With regard to a definition of startup, startup occurs when the mode

switch is placed in the "startup/hot standby" position and control

rod withdrawal is begun.

D. CONCLUSION

The ASME Code intended both system leakage and hydrostatic tests to

be performed prior to reactor criticality from a refueling outage.

The later Code position (footnote 7 to Table IWB-2500-1, Category

B-P), permitting the system hydrostatic test to be used in lieu of

the leakage test, is a clear indication that the Code intended the

system hydrostatic test also to be performed at low temperatures

consistent with fracture prevention considerations prior to reactor

startup.

E. REFERENCE

The guidance provided in this directive was extracted from a

memorandum from Robert M. Bernero, Director, Division of BWR

Licensing, NRR for Albert F. Gibson, Director, Division of Reactor

Safety, Region II, dated April 29, 1986; Subject: Interpretation

of System Pressure Test Requirements. The complete memorandum is

in the Document Control System (DCS 68390/353).

END